# New MFA method



## digital paradise (Feb 4, 2013)

Looks pretty good as it uses LV which is accurate and consistent as the base.

http://www.fredmiranda.com/forum/topic/1187247/0


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## J.R. (Feb 4, 2013)

digital paradise said:


> Looks pretty good as it uses LV which is accurate and consistent as the base.
> 
> http://www.fredmiranda.com/forum/topic/1187247/0



Interesting ... worth a try probably, not too much time involved in the steps


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## helpful (Feb 4, 2013)

Pure genius.

This is something so simple that even the camera manufacturers should be able to program it into their firmware.

Now wouldn't that be nice... just point the camera at a target at the distance where you wanted AF fine tune to be optimized, and press a button which would do this procedure instantly and electronically. You could even re-tune your cameras for a new distance (i.e., when shooting from the back row vs. front row) in real time on the job.

I'm definitely trying it. Why didn't we think of this before? It's so obvious.


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## neuroanatomist (Feb 4, 2013)

helpful said:


> Now wouldn't that be nice... just point the camera at a target at the distance where you wanted AF fine tune to be optimized, and press a button which would do this procedure instantly and electronically. You could even re-tune your cameras for a new distance (i.e., when shooting from the back row vs. front row) in real time on the job.
> 
> I'm definitely trying it. Why didn't we think of this before? It's so obvious.



Something similar has been suggested:

_In theory, it should be possible to achieve an ‘accurate’ focus using contrast detection in Live View, where no alignment is needed because the image sensor is used to determine best focus, then compare that to the phase detection AF and correct accordingly. In practice, this is something that’s difficult to do (because the act of moving the focus ring to see if you were really optimally focused changes the focus, and you lose the ‘zero point’). However, this is an idea that Canon could implement as a semi-automated routine, i.e. set up and align target (Canon could sell one, and suitably overcharge for it as they do for other small pieces of plastic *cough*), then the camera automatically determines the optimal adjustment. File that one under ‘gee, wouldn’t it be nice…’ _

Using AF Confirmation for manual focus to avoid having to move the focus ring is a nice solution!


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## Dylan777 (Feb 4, 2013)

Interesting...thanks for sharing


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## Apop (Feb 4, 2013)

looks really nice , i am going to try it tomorrow!


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## TrumpetPower! (Feb 4, 2013)

That is a really interesting solution.

However...the great thing about FoCal isn't just the automation, but the fact that it's automated.

I wonder, though, if this might inspire the FoCal crew to a faster way to do their magic. Is focus confirmation without focus available through the SDK?

b&


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## helpful (Feb 4, 2013)

What's even cooler about this method is that the sensor is used only once, at the very beginning. The imaging sensor isn't even used when performing the phase detection AF afterwards.

In contrast, using live view continuously as with FoCal, etc., slowly warms up the sensor and increases the noise and decreases the live view focusing accuracy.

So this method should give maximum accuracy, although it all is dependent on not bumping or vibrating the lens when flipping the switch to manual focus after the first live view photograph is taken.


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## RS2021 (Feb 4, 2013)

TrumpetPower! said:


> However...the great thing about FoCal isn't just the automation, but the fact that it's automated.



I use and like FoCal...but it is not fully automated with either 1DX or 5D3. "Change to -20, or +20, +10, -10, etc etc" is not exactly automation...and FoCal puts it on Cannon and I am sure Canon has no interest in making it easy for FoCal. Still, it is a great program.

But the approach in this post looks interesting.


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## comsense (Feb 4, 2013)

neuroanatomist said:


> helpful said:
> 
> 
> > Now wouldn't that be nice... just point the camera at a target at the distance where you wanted AF fine tune to be optimized, and press a button which would do this procedure instantly and electronically. You could even re-tune your cameras for a new distance (i.e., when shooting from the back row vs. front row) in real time on the job.
> ...


C'mon don't give half-hearted compliment. It's little more than similar. The crux here is to find the spread of focus distribution with MFA adjustment around the best focus achieved by live view. Its smart. Rather, what you quoted is very straightforward.


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## Viggo (Feb 4, 2013)

This could maybe have solved the problem with my Zeiss 28 f2, that hit spot on from infinity down towards mfd, but the other way it missed, have something in between would have helped.


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## TrumpetPower! (Feb 4, 2013)

helpful said:


> What's even cooler about this method is that the sensor is used only once, at the very beginning. The imaging sensor isn't even used when performing the phase detection AF afterwards.
> 
> In contrast, using live view continuously as with FoCal, etc., slowly warms up the sensor and increases the noise and decreases the live view focusing accuracy.
> 
> So this method should give maximum accuracy, although it all is dependent on not bumping or vibrating the lens when flipping the switch to manual focus after the first live view photograph is taken.



That's nothing a bit of gaffer's tape won't solve....

b&


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## Mantanuska (Feb 4, 2013)

I dont know much about AFMA since I've never owned a body that has the feature, but after finding the acceptable range with AF confirmation wouldn't you want to set it to a value that is on the first 3rd of the lower end instead of the midpoint, since the focal plane extends 1/3 in front of the subject and 2/3 behind?


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## neuroanatomist (Feb 4, 2013)

The 1/3-2/3 distribution only applies at short focal lengths, especially with close subjects.


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## digital paradise (Feb 4, 2013)

It will be interesting to get some feedback on how it works. I have always believed that an MFA system should be based on LV. As suggested it could be incorporated in the camera system.


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## Mt Spokane Photography (Feb 4, 2013)

Liveview AF (contrast Detect), at least on the 5D MK II and 7D has turned out to be inaccurate and inconsistent. The focus method described was one I used a couple of years back, its nothing new. Unfortunately, it is unreliable because it assumes thet Contrest Dect AF is accurate, but it has been shown to have errors, so much that FoCal had to change their software to accomodate the errors.

The most accurate methods still need about 10 shots setting the lens AF back to infinity or MFD and then throwing out obvious errors in focusing and averaging the others. Then, most shots will be in focus, but there will always be a few outliers. The 6D seem to have more accurate CD focus, the 5D MK II and 7D tends to be worse. The figures for the 5D MK III are not in yet.
http://www.reikan.co.uk/focalweb/index.php/2012/12/af-consistency-comparison-nikon-canon-phase-detect-contrast-detect/

I'd avoid this method if you have a 5D MK II or a 7D. FoCal which allows you to take a large number of shots at each AFMA setting is a great tool for ignoring obvious AF errors and picking the correct setting that gives the highest number of in focus shots.


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## horshack (Feb 4, 2013)

Hi everyone,

This is horshack (dpreview) / snapsy (FM), the guy who developed this AF tune technique. Don't get hung up on Live View - the fact that LV is used to establish critical focus (step 1) is only incidental to the process. You can use whatever focus method you want, including viewfinder AF or MF, LV contrast AF or MF...doesn't matter, as long as you establish and verify critical focus prior to starting the other steps.

What's unique about this technique is that you're using the confirmation dot and scaling the AF tune values to find the range and ultimate midpoint (final) AF tune value, all while keeping the same critical focus you established in step #1 (never refocusing). This avoids the mechanical AF variability that you get with all other MFA methods, since those involve reacquiring PDAF to verify focus, which in turn require multiple PDAF acquisitions/check cycles to normalize the PDAF variability out of the process.


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## neuroanatomist (Feb 5, 2013)

Thanks, Mt. Spokane - I had read those data, and forgotten about them. 



horshack said:


> Hi everyone,
> 
> This is horshack (dpreview) / snapsy (FM), the guy who developed this AF tune technique. Don't get hung up on Live View - the fact that LV is used to establish critical focus (step 1) is only incidental to the process. You can use whatever focus method you want, including viewfinder AF or MF, LV contrast AF or MF...doesn't matter, as long as you establish and verify critical focus prior to starting the other steps.



I wouldn't call it incidental. As you point out, establishing 'critical focus' is, well...critical. If LV is inconsistent, as the data indicate, there's no simple way to establish that baseline, certainly not with a single shot. Have you tested repeatability - several rounds of a single LV focus, resulting in the same selected AFMA value every time?

Have you, for example, used your method and selected an AFMA value 'on the edge' (one that gives confirmation where the next value out does not) then re-checked that value multiple times and seen confirmation every time, then the next value out and observed a lack of confirmation every time?

Thanks!


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## Plamen (Feb 5, 2013)

Mt Spokane Photography said:


> Liveview AF (contrast Detect), at least on the 5D MK II and 7D has turned out to be inaccurate and inconsistent.



The accuracy of LV depends hugely on the light level. Without knowing that, I would take those tests with a grain of salt. 

My own experience with the 5D2 and the 100L, LV, is as perfect focus as it gets, even in artificial but not too low light. In low light, it is unreliable or it just cannot focus when PD has no problems.


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## horshack (Feb 5, 2013)

neuroanatomist said:


> horshack said:
> 
> 
> > Hi everyone,
> ...



If by LV being inconsistent you mean its CDAF then sure it's by no means infallible, although it is rather precise, both in my experience and in Roger's LensRental tests. But again you don't have to rely on its consistency because you can verify critical focus visually at 10x and adjust manually if necessary before proceeding with my method. Or focus entirely manually if you prefer. If by inconsistent you mean that LV @ 10x isn't sufficient for visually confirming critical focus, then that I would disagree with that. But you can always take a photo to confirm focus if you don't feel LV can be trusted.

As for the repeatability of my technique, so far it's been very consistent in my tests, to within one or two AF tune units across iterations, when using the same target, focus distance, and lighting conditions between iterations. If you change any of these factors then you may certainly get different results, but those differences will arise from the sensitivity of the PD phase sensing mechanism itself rather than from this specific technique (ie, you'd get the same AF tune deltas using other MFA techniques in those situations).

As for the accuracy of the technique, I developed and tested it first on a D800 with 5 different lenses, all of which produced AF tune values equal or better than what I achieved via LensAlign. I have also tested it on a 5DM3 with two lenses so far, with the same level of accuracy. On my original dpreview for the Nikon version of the technique (link: http://forums.dpreview.com/forums/post/50774257), everyone who has tried it so far has achieved similar levels of accuracy. I think a few have compared it to Focal as well.


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## TrumpetPower! (Feb 5, 2013)

neuroanatomist said:


> If LV is inconsistent, as the data indicate(....)



Is it actual live view that you've found to be inconsistent (that is, not an accurate representation of what the sensor captures), or is it live view slow mode autofocus that's inconsistent?

If it's the latter, I can easily believe that...on more than one occasion when doing tripod work, I've improved upon the autofocus. For most stuff it's "good enough," but it's not the gold standard.

If it's the former, though...well, that'd be a huge problem, actually....

b&


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## Mt Spokane Photography (Feb 5, 2013)

CD focus using liveview is what is inconsistent (on some bodies, but not all). That green dot is part of the CD focus system, so it is suspect as well.
The liveview image you see is right off the sensor, and is the image you are getting, so you can use 10X and focus fairly well using the rear LCD. Its better if you tether to a large monitor though.


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## East Wind Photography (Feb 6, 2013)

But I think what he refers to is the green dot in PD mode not in CD mode. I agree LV does not always give you critical focus but it's a starting point and you can tweak manually from there. Here the use of a lenscal target, newsprint, or something like that would help get that LV 10X shot in perfect focus. So the question is the AF Detect system consistently flakey or just plain flakey? I tend to think it's consistently flakey and should work well in this case since you just trying to get the range and not an absolute.

We'll see, once I get over this flu I plan to try it out on my 300 2.8L and 600 F4L. It cant be any worse than focal in it's current state and if I dont have to carry my test setup out to a football field then it's worth it.



Mt Spokane Photography said:


> CD focus using liveview is what is inconsistent (on some bodies, but not all). That green dot is part of the CD focus system, so it is suspect as well.
> The liveview image you see is right off the sensor, and is the image you are getting, so you can use 10X and focus fairly well using the rear LCD. Its better if you tether to a large monitor though.


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## digital paradise (Feb 6, 2013)

That is the way understand it. Establish focus in LV, shut it and the AF off. In the viewfinder look for the green AF confirmation dot in the bottom right corner when half pressing the shutter. Located there on my 5D3 anyway. 

I just added to my post. The AF grid on the focus screen which is red lights up as well.


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## Mehmetski (Feb 6, 2013)

I will try this for sure


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## junkwerks (Feb 6, 2013)

So has anybody done the comparisons with the OP's suggested method and FoCal or similar? Can it be quantified in useful numbers as well as subjective picture examinations?


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## digital paradise (Feb 10, 2013)

Read post #15

http://www.fredmiranda.com/forum/topic/1187247/2


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## digital paradise (Feb 10, 2013)

digital paradise said:


> Read post #15
> 
> http://www.fredmiranda.com/forum/topic/1187247/2



Post #14 but that is just someones opinion. Not saying it is not accurate but there is no test data. Fred Miranda seems to think it is pretty good. It is not like the author or FM are making any money on it.

http://www.fredmiranda.com/forum/topic/1187247/2


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## horshack (Feb 10, 2013)

Btw I've decided to put a name to the technique so that everyone has an easy way to refer to it and to make it web searchable as it evolves with any improvements. I'm calling it "DotTune", since the focus confirmation dot is central to the technique. I'm also working on a youtube video to bring it to a wider audience.


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## caruser (Feb 10, 2013)

Tried this yesterday evening, and except for being a bit shocked for how much adjustment my shiny new 1DX needed (only the [email protected] came out at 0) it actually worked pretty well, that is when I double-checked some of the obtained values they were spot on...


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## digital paradise (Feb 10, 2013)

DotTune. I like it. I'm going to have to wait several days try this with the suggested outer limit AF confirmation. Baby sitting an 11 week old pup and he is into everything. Always under my feet .


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## Rienzphotoz (Feb 10, 2013)

horshack said:


> Btw I've decided to put a name to the technique so that everyone has an easy way to refer to it and to make it web searchable as it evolves with any improvements. I'm calling it "DotTune", since the focus confirmation dot is central to the technique. I'm also working on a youtube video to bring it to a wider audience.


Excellent job and a neat name ... what I like about this technique is that it is simple, pretty much anyone can do it without having to break their head. AWESOME! ... keep up the good work!


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## wayno (Feb 11, 2013)

Tried this this morning on two lenses - my 85 1.4 Siggy and my 35L. -1 and +1 respectively, which correlates very closely with what I knew. My ranges of AF cut out for both were in the order of +9 and -9 (or thereabouts) - so a range of about 18. This seems like a pretty logical and effective method to me.


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## Meh (Feb 11, 2013)

Well, this makes FoCal and LensAlign obsolete... or does it? Could there still be any advantage to a FoCal type method and, if so, how much better might it be? 

The points made about being able to achieve critical/perfect/best (or whatever you might call it) focus using CD are valid, but I think it's a reasonable assumption that manual focus at 10x live view can get real darn close to perfect focus... anyone have any experience with that?

But, maybe perfect focus or repeatability don't matter so much... even using a theoretically "perfect" method only gets a theoretically "perfect AMFA setting" at one distance. If we accept that the AFMA setting can not be perfect anyway for all subject distances and focal lengths (for a zoom lens) and all we are trying to do is identify substantial systematic PD focus error and adjust to get closer to the centre of the focus variability then this method may do the job quite well.

Are we sure the focus confirmation dot in the viewfinder works exactly how we think it does? Does testing for the range of focus confirmation while in MF mode actually give us the centre of the focus variability when PDAF is functioning normally?

Hmmmm.... I suspect we'll see an official word from FoCal why this method doesn't work so good and we will all read it and collectively say "nice try, bye bye".


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## caruser (Feb 11, 2013)

Meh said:


> Hmmmm.... I suspect we'll see an official word from FoCal why this method doesn't work so good and we will all read it and collectively say "nice try, bye bye".


Sorry to be cynical, but we live in a day and age where people and companies with any kind of commercial interest are known to tell a lot of lies and even defend them in court if it means that they can, well, maximise profit. They might of course really have something, but anything they say will have to be double checked. And although I'll have to do some more tests, as I wrote above, double checking this new method the other day indicated that it was spot on for me.


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## nolken (Feb 11, 2013)

Sounds like this would be a good Magic Lantern implementation.


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## celliottuk (Feb 11, 2013)

One advantage of this method is that it will work regardless of operating system. FoCal continues to not work with Windows 8 on 2 out of my 3 cameras


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## wayno (Feb 11, 2013)

Even accounting for a margin of error of say 1-2 on the AFMA scale, I think this is a perfectly valid approach. I don't believe 1-2 (for example) would be noticeable in real life shooting. Essentially I think this method would satisfy 80-90% of AFMA users, even considering AFMA users are a pretty anal bunch


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## Meh (Feb 11, 2013)

caruser said:


> Meh said:
> 
> 
> > Hmmmm.... I suspect we'll see an official word from FoCal why this method doesn't work so good and we will all read it and collectively say "nice try, bye bye".
> ...



That was in fact my point... that Focal will issue a explanation of why this DotTune doesn't work but we will say "nice try" to them. You hit the nail on the head... in order to protect their business they will come up with a reason even if it isn't quite true or if it overstates the advantage of their method.


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## ddl (Feb 11, 2013)

Focal has the advantage of doing everything automatically (when it works as I've had the odd crash plus 5D3 is semi-auto) plus providing some data analysis and documentation that you can refer to later.

The question is whether that is of any tangible $ value to you if the end result is the same. I like automation (not having to touch the camera once the test is set up) and documentation so it would probably be worth it for me.


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## comsense (Feb 11, 2013)

I remember all the posts on CR about light and stability requirements for doing FoCal with slight failure resulting in wrong AFMA. Add software glitches, compatibility issues and hooking up laptop to it. In the end, the fact that it can do AFMA automatically is a very small part of the effort (considering you don't even need laptop/image analysis with other method). 

However, its not about justifying the FoCal purchase or vice-versa. I don't see FoCal going out of business right away, although it will be a serious dent in their business. Hey, not so long ago, people were happily buying a piece of plastic and a ruler worth $1.5 for $70-100. Ideally, it would be best for most people if we could hand over our Camera-Lenses to a competent assistant who can do the job for us, if we can afford and/or justify the need. 

So, I think the question should be asked in reverse: Does this method allow to get the job done with comparable effort and accuracy for someone who does not want to buy FoCal?


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## East Wind Photography (Feb 12, 2013)

I just tested on a 5DIII and a 600 F/4L with 1.4xIII extender. Range was -1 to +17. DOuble checked both ends of the range. So AFMA value would have been +8. Took a series of shots and discovered focus was off. Manually worked down the AFMA range through a series of shots and determined that AFMA 0 produced the sharpest in focus image of the target. So in this case the Dot Method did not work as expected.

Some thoughts about the process.

1) Live view and phase detect focus may respond differently to color variations in your target or the type of lighting used. I was shooting in daylight using a concrete wall with several cracks converging to a point. Not Black and White target.

2) My LV focus may not have been "accurate" such that the predicted AFMA setting was off from where it should have been. but off by 8??? That would have been noticeable as 8 = a full DOF.

3) AF detect may operate differently depending on object color, contrast, type of lighting used.

So my point here is that there are additional variables to consider that could affect the results. We put a lot of trust in the camera to do what it's supposed to do on a consistent basis and in fact it's not as consistent as one might think. You still need to use common sense when making these kinds of adjustments.


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## Mehmetski (Feb 13, 2013)

I tried this today on the 5d3 with my 50L 1.2 and 16-35II's long end and it gave me very inconsistent results. I did this on a controlled light setup, marked my positions at max distance for both lenses, wide open aperture and aligned the target (from lens-align) parallel to the sensor. I tried this technique 3 times on the same positions with both lenses. I shut down the camera and restarted the test after each try. These are the results:
50mm 1.2
first try -5 to +12
second -9 to +9
third -8 to +16

16-35II on 35mm
first try -9 to 10
second -5 to +14
third -6 to +12

Did I do something wrong?


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## East Wind Photography (Feb 13, 2013)

Nope. As mentioned previously I had the same kinds of error. So in essence the method is flawed. Relies on an accurate AF confirm which we all have known for some time is pretty darned useless.

It's a very nice concept and one that someday may be refined enough to actually be built into firmware. Right now it's even worse than FoCal.



Mehmetski said:


> I tried this today on the 5d3 with my 50L 1.2 and 16-35II's long end and it gave me very inconsistent results. I did this on a controlled light setup, marked my positions at max distance for both lenses, wide open aperture and aligned the target (from lens-align) parallel to the sensor. I tried this technique 3 times on the same positions with both lenses. I shut down the camera and restarted the test after each try. These are the results:
> 50mm 1.2
> first try -5 to +12
> second -9 to +9
> ...


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## horshack (Feb 14, 2013)

East Wind Photography said:


> Nope. As mentioned previously I had the same kinds of error. So in essence the method is flawed. Relies on an accurate AF confirm which we all have known for some time is pretty darned useless.
> 
> It's a very nice concept and one that someday may be refined enough to actually be built into firmware. Right now it's even worse than FoCal.
> 
> ...



I'm actually surprised at how few people have reported DotTune isn't working for them. Not because I don't have confidence in my method, but because I expected the teething period to last longer as people sorted out the nuances of the viewfinder focus confirmation system, not to mention the percentage of users who report MFA issues using even existing methods. In my original dpreview Nikon thread the success rate was close to 100%, whereas on the Canon FM thread there were quite a few more people with issues. But nearly everyone who had problems later reported back and said the method worked for them once they followed the additional guidance I posted in my follow-up posts on that FM thread.

As for the accuracy and precision of the viewfinder confirmation system, I've actually found it to be extremely accurate on both the Nikon and Canon bodies I tried. But it takes patience, diligence, and some practice work through the nuances of its feedback.


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## East Wind Photography (Feb 14, 2013)

It's of no use to me when the AFMA setting is off by 8, a full DOF. Maybe Nikon has better AF confirmation.



horshack said:


> East Wind Photography said:
> 
> 
> > Nope. As mentioned previously I had the same kinds of error. So in essence the method is flawed. Relies on an accurate AF confirm which we all have known for some time is pretty darned useless.
> ...


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## Meh (Feb 14, 2013)

horshack said:


> As for the accuracy and precision of the viewfinder confirmation system, I've actually found it to be extremely accurate on both the Nikon and Canon bodies I tried. But it takes patience, diligence, and some practice work through the nuances of its feedback.



What "nuances of it's feedback"? The light either comes on, or it doesn't.


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## digital paradise (Feb 14, 2013)

Not sure if it was here or elsewhere that the author and testers determined that when you get to the point where the AF green dot flickers or delays then you went too far. It can do that for 3 or more values - negative or positive.

The last value where the green dot shows AF lock instantly is the stopping point. If the next value flickers or hesitates even for a bit use the previous value. Not sure if the members that are having mixed results are following this. It happened to me when I did not stop and kept going until there was no AF confirmation at all. Negative side was consistent but the positive side was +16 one time and +20 the next. 

I have yet to test this but Fred Miranda at FM forums stated it appeared more accurate.


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## nicku (Feb 14, 2013)

Interesting.... I have a Sigma 50mm f/1.4, that need AFMA. i will try it


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## J.R. (Feb 14, 2013)

digital paradise said:


> Not sure if it was here or elsewhere that the author and testers determined that when you get to the point where the AF green dot flickers or delays then you went too far. It can do that for 3 or more values - negative or positive.
> 
> The last value where the green dot shows AF lock instantly is the stopping point. If the next value flickers or hesitates even for a bit use the previous value. Not sure if the members that are having mixed results are following this. It happened to me when I did not stop and kept going until there was no AF confirmation at all. Negative side was consistent but the positive side was +16 one time and +20 the next.
> 
> I have yet to test this but Fred Miranda at FM forums stated it appeared more accurate.



Thanks for the information. I've been testing this till the AF confirmation is no longer available and have been getting incorrect results. 

I'll test again and see what happens.


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## AlanF (Feb 14, 2013)

To those have made repeat measurements and have found different values - you are experiencing the life of a scientist. All measurements are subject to random and systematic errors. Just repeat the experiment several times and use the average value, unless some of the values are absurd. Errors can obviously arise from the initial focussing or during the dot confirm. I would not consider a series of AFMAs of say for example 2, 6, 4, 3, 3, 0 to be wrong but merely a mean of 3 with a not unsurprising standard deviation.


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## cervantes (Feb 14, 2013)

snapsy aka horshack aka the guy that killed Reikan Technology Ltd ???

I've never used AFMA but I'll give it a try tonight!


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## East Wind Photography (Feb 14, 2013)

And then you will find that your focus is no better than if you just turned off AFMA. The setting is not something that you can average based on a set of bad values. You can be off by 1 but any more than that and you are off. 1 AFMA is 1/8 of the depth of field. For most telephoto lenses where AFMA makes the biggest change being off by 1 wide open makes a difference wether the eye of you subject is in focus or not. There can be no guessing and no averaging of test values. The setting has to be exactly where it needs to be. The dot method doesn't get you there. You still need to run your photo tests and dial in the setting.



AlanF said:


> To those have made repeat measurements and have found different values - you are experiencing the life of a scientist. All measurements are subject to random and systematic errors. Just repeat the experiment several times and use the average value, unless some of the values are absurd. Errors can obviously arise from the initial focussing or during the dot confirm. I would not consider a series of AFMAs of say for example 2, 6, 4, 3, 3, 0 to be wrong but merely a mean of 3 with a not unsurprising standard deviation.


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## digital paradise (Feb 14, 2013)

I jokingly asked snapsy when he was coming out with software. I had in mind doing this test several times to include variation and get the best value. Obviously this was meant to be a quick method so software just slows it down. It is so quick to use that it would take no time to go through it several times putting the lens OOF between the tests. Next week I will give it a good run. 

So East Wind. Are you saying that the same issues apply to FoCal and Focus Tune? I normally send my lenses to Canon because I prefer a trained technician with the correct tools to tune my lenses. It is a pain so I am always looking for new method.

I have not tried FoCal but did try Focus Tune with mixed results. Also I tried every other method out there in the last several years. I won't use any method where I have to visually make a decision. I want the method to tell me what value to use.


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## AlanF (Feb 14, 2013)

East Wind Photography said:


> And then you will find that your focus is no better than if you just turned off AFMA. The setting is not something that you can average based on a set of bad values. You can be off by 1 but any more than that and you are off. 1 AFMA is 1/8 of the depth of field. For most telephoto lenses where AFMA makes the biggest change being off by 1 wide open makes a difference wether the eye of you subject is in focus or not. There can be no guessing and no averaging of test values. The setting has to be exactly where it needs to be. The dot method doesn't get you there. You still need to run your photo tests and dial in the setting.
> 
> 
> 
> ...



The nature of making any measurement is that your results will fit a normal or skewed Gaussian distribution. The more measurements you make, the closer your result will be to the true one. FoCal fits its measurements to a Gaussian curve. Taking an average of a series of measurements is surely better than turning AFMA off. Canon does not claim to have an accuracy in any one shot to 1 unit. Look at the spread of data in the lens rental analysis where they quote the equivalent of a standard deviation for repeat measurements on different bodies etc.


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## neuroanatomist (Feb 14, 2013)

East Wind Photography said:


> 1 AFMA is 1/8 of the depth of field.



Point of clarification... 1 unit of AFMA is 1/8 the depth of _focus_, not depth of field. The AF system doesn't know subject distance (that's estimated by the lens after focus is achieved). Depth of focus is measured at the AF sensor itself (micron distances). The practical consequence is that a unit of AFMA has more impact on depth of field the closer the subject is to the camera.


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## East Wind Photography (Feb 14, 2013)

I would have thought it would have more impact on subjects at farther distance and less effect at closer distances. Otherise we would be AFMA testing at closer distances. either way it must be coincidence then that 8 units appear to equal the depth of field on my 600 F4.



neuroanatomist said:


> East Wind Photography said:
> 
> 
> > 1 AFMA is 1/8 of the depth of field.
> ...


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## David Hull (Feb 14, 2013)

horshack said:


> East Wind Photography said:
> 
> 
> > Nope. As mentioned previously I had the same kinds of error. So in essence the method is flawed. Relies on an accurate AF confirm which we all have known for some time is pretty darned useless.
> ...



It seems simple enough for a peerson to run your proposed methodology and compare it to what he done using some previous method and see if the results are similar. I did it quickly on several lenses last weekend and got roughly the results I expected (i.e. it appeared to work -- not surprising since it seems technicaly sound). I find that all of my glass (on the 5DIII anyway) is within +/- a couple tics of 0 and that didn’t change from what I did with my previous methodology. The 50 1.4 wanted -7 which was a little more than previous for some reason (maybe I screwed the pooch somewhere on that one).


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## AlanF (Feb 14, 2013)

Disappointingly, it didn't work for me. My 300mm f/2.8 is +8 on FoCal and sloping ruler tests, but +2 on the Dot. With a 2xTC, it is +6 on FoCal and slope and -8 on the dot. For the latter, the actual image at +6 was the same quality as live view and -8 out of focus.

The method did work spot on for the 100-400mm L. The series II telephotos do have sophisticated focussing algorithms and perhaps they don't work so well with the manual focussing dot. It is surprising that the green dot lights up over a range of 20 units.


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## AlanF (Feb 15, 2013)

I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.


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## neuroanatomist (Feb 15, 2013)

AlanF said:


> I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.



Thanks for the update (despite the bad new for DotTune® fans  ).


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## horshack (Feb 15, 2013)

AlanF said:


> I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.



Can you elaborate on the difference in target+methodology you're using between DotTune and whatever MFA method you're using for "recalibration"? For DotTune are you tuning to a flat DOF vs a 3-D DOF using the other MFA method? I'm asking because when DotTune is used against a flat target with no DOF reference (chart on wall), then you're tuning an unknown point within the DOF plane. It could be you're tuning at the very edge of the DOF range but you wouldn't be able to know this from a flat target. The alternative would be to DotTune against a target with a 3-D DOF reference, like a LensAlign target. I'd be appreciative if you could try this and report back the results. Thanks!


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## AlanF (Feb 15, 2013)

Last night I used a patterned lampshade with a bulb behind it as I can do this at night easily. This afternoon, I printed a black + on white A4 paper and focused on that. I did the sloping ruler test on both reproducibly. I have also checked visually using the standard iso chart.


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## comsense (Feb 16, 2013)

neuroanatomist said:


> AlanF said:
> 
> 
> > I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.
> ...


From someone who is not a fan of either of the methods: you know very well that there are plenty who cant get it right with either simple ruler or FoCal. 
People from companies are known to spread confusion on the forums. Also, online forums are magnet for people who would go to absurd lengths to justified their biased views. Not long ago there was thread full of posts saying "6D is the best full frame camera made by Canon". 
So, instead of taking stand at this point I would just wait and watch and try it myself next time I need AFMA.


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## AlanF (Feb 16, 2013)

horshack said:


> AlanF said:
> 
> 
> > I checked the method again today with the 300 f/2.8 series II plus extenders using a high contrast black cross on white in good light. In all cases, the dot method was way out. Recalibration using the same target and sloping ruler was within 1 unit of previous.
> ...



Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work. For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target. It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.


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## digital paradise (Feb 16, 2013)

Page 4, Post #10. There is also a link to an article at DPreview. Some light reading  

http://www.fredmiranda.com/forum/topic/1187247/3#11352268


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## horshack (Feb 17, 2013)

AlanF said:


> Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work. For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target. It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.



The advantage of a LensAlign target is that the flat 2-D surface serving as the AF target is machined to be on the same focus plane position as the "0" on the ruler attached to the target, whereas home-grown solutions may not be able to guarantee this tolerance. The LensAlign target also has a sight reference built into it to assure alignment between the camera and the target.


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## AlanF (Feb 17, 2013)

The "0" of my home grown system is placed in the same plane as the target. The ruler rests at about 30deg at the side of a cardboard box and the target is pasted on the front face. The line on the ruler that touches the target is the 0 point. The target is perpendicular to the line of sight from the camera. What is not working is the dot assist on manual focussing relative to focussing in live view. Does anyone use manual focussing and the dot assist regularly - the spread of 15-20 units is not impressive? Maybe my mistake has been to use the automatic focussing in live view and not tether to a computer and blow up for manual focussing in live view?


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## East Wind Photography (Feb 17, 2013)

One of the good things about FoCal is that it has a new software method for calculating an accurate focus using live view which uses a focal algorithm instead of either PD or CD built into the camera. It's very slow but meticulous.

IF you want to make sure the dot method is working best, you can use focal to obtain the perfect focus, switch to MF on the lens then continue with dot method.

Still, it is not accurate in my testing on both the 5DIII and 1DX but at least you can use it to ensure perfect focus prior to any testing.



AlanF said:


> The "0" of my home grown system is placed in the same plane as the target. The ruler rests at about 30deg at the side of a cardboard box and the target is pasted on the front face. The line on the ruler that touches the target is the 0 point. The target is perpendicular to the line of sight from the camera. What is not working is the dot assist on manual focussing relative to focussing in live view. Does anyone use manual focussing and the dot assist regularly - the spread of 15-20 units is not impressive? Maybe my mistake has been to use the automatic focussing in live view and not tether to a computer and blow up for manual focussing in live view?


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## comsense (Feb 17, 2013)

horshack said:


> AlanF said:
> 
> 
> > Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work. For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target. It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.
> ...


You have lost a lot of your credibility with your nonsensical argument. You are underestimating the capability of some user to achieve precision (same or better than LensAlign). Even then, why is 0 important? Even if 2D target is aligned to 2; you could look around 2. Finally, how is 0 alignment relevant to AFMA by your method? If you need complex 3-D target you got one irrespective.....
Are you CEO of LensAlign resorting to drastic measures to boost sales? 
From easy to use with any target, any distance in field about your method, the fine print is creeping in - You need to buy LensAlign target, just to test the method? If someone has to spend $$'s, FoCal already works well!!!!


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## horshack (Feb 17, 2013)

comsense said:


> horshack said:
> 
> 
> > AlanF said:
> ...



I suggested a LensAlign target only for those that want to DotTune to a precise point within the DOF range. It's not necessary to the process. I'm not affiliated with either LensAlign or FoCal. Also, as an FYI, LensAlign is coming out with their own software product to compete with FoCal: http://www.tapestalk.com/2012/10/focustune-the-rumors-are-true.html


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## Jaguar2012 (Feb 17, 2013)

I wonder if Focal Method "TurboCal" is using similar technique as "DotTune" to perform MFA prediction in 30 Seconds with no shutter activation in an automated way.

http://www.reikan.co.uk/focalweb/index.php/2013/02/focal-1-8-release-candidate-available-for-focal-pro-users/


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## horshack (Feb 17, 2013)

Jaguar2012 said:


> I wonder if Focal Method "TurboCal" is using similar technique as "DotTune" to perform MFA prediction in 30 Seconds with no shutter activation in an automated way.
> 
> http://www.reikan.co.uk/focalweb/index.php/2013/02/focal-1-8-release-candidate-available-for-focal-pro-users/



Thanks for the link! I agree, they might be doing something similar to DotTune, provided the Canon SDK+USB interface provides a way to both change the AF tune value programmatically and also feed the PDAF evaluation information over USB to the computer as well.


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## comsense (Feb 17, 2013)

horshack said:


> comsense said:
> 
> 
> > horshack said:
> ...


If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!


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## Larry (Feb 17, 2013)

comsense said:


> If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!



Aren't you asking a group who are discussing how to achieve precise focus why they would want to do this, ...if they didn't want to do this?

Well yeeesss, if you didn't want to focus precisely, then you wouldn't need to adjust your camera/lens combo to focus precisely!

Am I missing something?


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## AlanF (Feb 17, 2013)

Larry
Comsense is not saying he doesn't want to have precise focus. He is complaining that Horshack hasn't explained clearly what he meant in his reply to my earlier message, Horshack also confused me, and he hasn't replied to my last questions to him, four or five posts back.


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## horshack (Feb 17, 2013)

comsense said:


> If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!


DOF is defined as the range of distances between the camera and subject that will be rendered with sufficient sharpness for a given viewing or print size. Since DOF is not a precise point but instead a range, when you tune to a 2-D object you can't be sure what the balance of front/rear DOF will be relative to the 2-D point you're tuning to. This is fine if you'll be shooting with enough DOF for everything you need to be sharp, or if you're shooting 2-D real-life subjects. However if you're shooting in DOF-limited situations (small DOF, like f/1.4), many times you'll want to know or specify the precise balance of DOF relative to where the AF is tuned to, for example when shooting a portrait where you want both the eyes and nose to be in focus vs eyes and ears or eyes and hiar.


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## horshack (Feb 17, 2013)

AlanF said:


> The "0" of my home grown system is placed in the same plane as the target. The ruler rests at about 30deg at the side of a cardboard box and the target is pasted on the front face. The line on the ruler that touches the target is the 0 point. The target is perpendicular to the line of sight from the camera. What is not working is the dot assist on manual focussing relative to focussing in live view. Does anyone use manual focussing and the dot assist regularly - the spread of 15-20 units is not impressive? Maybe my mistake has been to use the automatic focussing in live view and not tether to a computer and blow up for manual focussing in live view?


Again, precise use of a 3-D target to establish the DOF balance requires tight tolerances between the 2-D target and the 3-D portion (ruler), along with a mechanism to calibrate alignment between the camera and target.


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## comsense (Feb 18, 2013)

horshack said:


> comsense said:
> 
> 
> > If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!
> ...


I understand DOF. For good or worse, I have physics/spectroscopy background. What you have still not explained is why LensAlign target is so critical compared to 2-D target with precisely placed ruler? On practical note, you need AFMA only when you are using larger apertures/ small DOF except for rare manufacturing/ quality control failures. And front/back focusing you refer to as 'balance' is actually part of performing AFMA. So, essentially you are saying that one needs to find front/back focus with LensAlign target to use your precise dot tune? What I also fail to understand is that if you get that far, it does not take a lot more to do AFMA. So why bother with dot tune? If i have to spend money/time why not on something that works for sure? Again, neither against nor for; just trying to understand.


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## sama (Feb 19, 2013)

see another post in this forum with video tutorial : http://www.canonrumors.com/forum/index.php?topic=13056.msg234394;topicseen#new


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## East Wind Photography (Feb 19, 2013)

Still doesnt work even with a video! ;D



sama said:


> see another post in this forum with video tutorial : http://www.canonrumors.com/forum/index.php?topic=13056.msg234394;topicseen#new


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## AlanF (Feb 20, 2013)

I have suggested why DotTune fails in the DotTune Video thread. Maybe failure means the camera should be sent back to Canon for calibration.


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## kaihp (Feb 20, 2013)

horshack said:


> Jaguar2012 said:
> 
> 
> > I wonder if Focal Method "TurboCal" is using similar technique as "DotTune" to perform MFA prediction in 30 Seconds with no shutter activation in an automated way.
> ...


FWIW, I forwarded a link to this discussion to Reikan some days ago. I have no idea if their method is the same nor if they have acted independently or not.


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## East Wind Photography (Feb 20, 2013)

Yeah I replied to you on that. I think there are more factors that can throw off the Dot tune method including non-symmetric AF detect. Different lenses have different in-focus characteristics and while not a defect causes the AF detect to respond in a non-symmetric way. Some lenses have more DOF behind that subject than in front, other lenses just focus differently in front or behind the subject. ex: front focus yields good blur...back focus starts producing halo's before it begins to blur. AF detect may get confused in that scenario.

I don't believe it's a good way to tell if your camera is out of spec and I still believe it's a bad way to calculate AFMA due to the many factors that can throw it off. YOu still need to verify with a 3D calibration target or something similar and at that point you might as well just do it manually.



AlanF said:


> I have suggested why DotTune fails in the DotTune Video thread. Maybe failure means the camera should be sent back to Canon for calibration.


----------



## comsense (Feb 20, 2013)

East Wind Photography said:


> Yeah I replied to you on that. I think there are more factors that can throw off the Dot tune method including non-symmetric AF detect. Different lenses have different in-focus characteristics and while not a defect causes the AF detect to respond in a non-symmetric way. Some lenses have more DOF behind that subject than in front, other lenses just focus differently in front or behind the subject. ex: front focus yields good blur...back focus starts producing halo's before it begins to blur. AF detect may get confused in that scenario.
> 
> I don't believe it's a good way to tell if your camera is out of spec and I still believe it's a bad way to calculate AFMA due to the many factors that can throw it off. YOu still need to verify with a 3D calibration target or something similar and at that point you might as well just do it manually.
> 
> ...


+1 exactly the point I made in my earlier thread. Front/back focussing is one of the common reason to perform AFMA and with 3D target, your job is mostly done anyways....


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## Knut Skywalker (Feb 20, 2013)

Just found out my 50mm 1.4 is -11 on my 5D Mark II.  The difference is mind-blowing. Thank you so much for this.


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## digital paradise (Feb 20, 2013)

Knut Skywalker said:


> Just found out my 50mm 1.4 is -11 on my 5D Mark II.  The difference is mind-blowing. Thank you so much for this.



So there is a noticeable difference in your shots now or you just providing the values after testing with DotTune?


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## Knut Skywalker (Feb 20, 2013)

The photos with the 50mm 1.4 are significantly sharper now that i found its "sweet spot". I knew that the 50mm 1.4 wasn't the sharpest lens wide open and i thought this would be normal, but now the photos have a good sharpness even wide open.


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## digital paradise (Feb 20, 2013)

Knut Skywalker said:


> The photos with the 50mm 1.4 are significantly sharper now that i found its "sweet spot". I knew that the 50mm 1.4 wasn't the sharpest lens wide open and i thought this would be normal, but now the photos have a good sharpness even wide open.



That is good to hear. The author is getting some heat on this method here and I don't really know (and I have absolutely no interest) the technical aspects as to why or why not it would not work. All I need to know is that it works for me. I've been busy but I want to try it on one my suspect lenses with the new focus acquisition method. 

It is getting good reviews on other sites. Fred Miranda is a pretty respected photographer and he liked it.


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## East Wind Photography (Feb 20, 2013)

So lets start out by saying that a 50mm 1.4 has DOF at 12ft of about 17" assuming a full frame body. you could be within +-3 or 4 AFMA and still get pretty sharp images. Dot method might have gotten you there or it might have just got you close within the acceptable DOF. Either way for you that would be good because your images are sharper.

Where the method breaks down is when we start using long telelphotos where exact AFMA is more critical such as when your DOF is 6" or less wide open. Off by 1 AFMA will give you soft images with an occasional in focus shot.

As I described earlier every lens has it's own unique characteristics too and if you are looking for exactness and not just getting you close enough, then you need to use a 3D target such as a lensalign or some other targeting and measuring system to, if not make the proper AFMA selection, but to at least verify that you have selected the best AFMA for your lens/camera combination.



Knut Skywalker said:


> The photos with the 50mm 1.4 are significantly sharper now that i found its "sweet spot". I knew that the 50mm 1.4 wasn't the sharpest lens wide open and i thought this would be normal, but now the photos have a good sharpness even wide open.


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## East Wind Photography (Feb 20, 2013)

To give credit where credit is due (because I have been seriously harsh about Dot Tune) I applaud horshak for thinking out of the box to come up with an alternative solution to AFMA calibration. We need more people that think like that to come up with new technologies to improve the tools we use.

I just feel that AF detect was never intended do such and therefore is not accurate enough at this time to make it reliable. Now that Dot tune is out there, lets hope the vendors take him seriously and start to refine the AF detect system and then adopt it as a a standard firmware option built in to cameras to do this automatically.

It is simply groundbreaking. Time will tell if it gets adopted by Canon, Nikon or any other maker and I hope it does.


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## horshack (Feb 20, 2013)

East Wind Photography said:


> To give credit where credit is due (because I have been seriously harsh about Dot Tune) I applaud horshak for thinking out of the box to come up with an alternative solution to AFMA calibration. We need more people that think like that to come up with new technologies to improve the tools we use.
> 
> I just feel that AF detect was never intended do such and therefore is not accurate enough at this time to make it reliable. Now that Dot tune is out there, lets hope the vendors take him seriously and start to refine the AF detect system and then adopt it as a a standard firmware option built in to cameras to do this automatically.
> 
> It is simply groundbreaking. Time will tell if it gets adopted by Canon, Nikon or any other maker and I hope it does.



I appreciate that, thanks. I welcome all feedback about DotTune, both positive and negative. I put DotTune out there because I think it has the potential to help a lot of DSLR owners succeed at a process that has traditionally been error prone and frustrating, so any feedback which improves and evolves the method is highly encouraged.

Regarding the AF detect and the VF confirmation dot, I have a hunch that the "slop" in the dot might actually be by design. Since the VF dot was designed primarily as a manual-focusing aid, I'm thinking both Canon and Nikon thought making the dot too precise would mean manual focusing would be too slow and require too much dexterity of the focus ring by the shooter. For static shooters with lots of time it would be ok, but for anyone shooting dynamic stuff like street-shooting I think a very-tight range of dot-confirmation would be a negative in practical terms. This is partly why I think using the midpoint of the dot-confirmation range for AF tuning works so well.


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## Kent (Feb 20, 2013)

Automation investigation request started at Magic Lantern.
http://www.magiclantern.fm/forum/index.php?topic=4648.0


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## PhotoCat (Feb 21, 2013)

Just successfully tuned my 50/1.8 & 85/1.8 with this dot-tune method with my 5d2.
There is no question in my mind that horshack's new MFA method works and works consistently.
Thanks for sharing this brilliant idea horshack!

To get a consistent result in my 50/1.8, I had to gaffer tape the focus ring of the 50/1.8 
so it doesn't move right after manual focusing (x10) in LV.

Getting the AFMA value for 85/1.8 was easy as it was in range: -18 to -1, meaning a AFMA value of -10.

However, it was a bit more tricky for the 50/1.8 as the dot remains red at -20 and the upper range was -4.
-4 should be credible but -20 is questionable and it could be -21, -22, -23 etc but the scale doesn't show it.

So I was guessing horshack's "detuning method" and detuned the focus a bit.
I did so by first setting AFMA to +5 (guessing) and turn the focus ring manual until I get a beep (red dot).
So now I know +5 is within range. Based on this detuned focus, using the dot-tune method gives me a range
of -9 to +9. So I know the half range is 9. Based on the credible upper value of -4 and subtracting 
9 (half range) from it gave me a final value of -13.

Using the obtained AFMA values gave me much sharper images at f1.8 at the distance I performed the calibration. (distance suitable for a full-length shot)

So in my mind, the dot-tune method is solid. What is questionable to me is the 
implementation of AFMA, as it seems subject distance dependent. 

For example, my 85/1.8 with AFMA of -10 works great with full length portraits but I will get soft images at a distance of 10 feet and closer. The 50/1.8 seemed to work well with AFMA of -13 at all distance with the calibration target and lighting. However, it doesn't work very well with somce other subjects and lighting. So I just have to turn off AFMA in case of doubt.

I feel this kind of AFMA is a bandage solution anyway and I am hoping Canon will incorporate their factory lens 
calibration routine into EOS Utility and I will be laughing! No more "bad copies" of lens... sigh...
Note the competition already has "USB lens dock" for factory strength lens calibration LOL!


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## Mehmetski (Feb 21, 2013)

Repeat these steps after restarting your camera. It will give you different values.


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## East Wind Photography (Feb 21, 2013)

So you say it works consistently but you also put in caveats that it doesnt work if the lighting or distance to subject changes? 

So it seems to me that it's not consistent in your case and the results are questionable. Did you verify that the selected AFMA was indeed correct using a 3D type of focus tester? You can set up one easy enough using a yard or meter stick slanted at a sharp angle and fixing a flat high contrast target next to it to focus on.

I've been seriously trying to explain that unless you have a way of verifying the AFMA setting is correct most people should just disable it. As you noticed that it can get you into some trouble.

Some lenses just dont focus well on a linear scale. Some need different AFMA settings focused far than focused close. To me that's a manufacturing flaw or the lens is just out of spec and needs adjusting. In those cases you either need to set the AFMA for the distance you use it the most, or split the difference in the near and far AFMA tests and use aperture to increase the DOF and mask the error.

Either way you need an accurate method of verifying the settings as AF detect is not very accurate in most of the current models.



PhotoCat said:


> Just successfully tuned my 50/1.8 & 85/1.8 with this dot-tune method with my 5d2.
> There is no question in my mind that horshack's new MFA method works and works consistently.
> Thanks for sharing this brilliant idea horshack!
> 
> ...


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## PhotoCat (Feb 21, 2013)

Sorry for the confusion if any.
By "consistent" result, I meant dot-tune always gives me the same AFMA value with the same
target and lighting. No, I did not mean consistent focusing under whatever shooting condition and
distance after AFMA.

I will try the 3D target as u had suggested. No, both of my 85/1.8 and 50/1.8 did not magically
become perfect after AFMA. It just improved focusing accuracy at a specific distance I chose while it suffered
at other subject distance. It is a tradeoff. 
As I had said, AFMA is a bandage solution at best but that has nothing to do
with the dot-tune procedure which is giving consistent value for me for a fixed target, fixed lighting and
distance.


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## PhotoCat (Feb 21, 2013)

East Wind Photography said:


> Some lenses just dont focus well on a linear scale. Some need different AFMA settings focused far than focused close. To me that's a manufacturing flaw or the lens is just out of spec and needs adjusting. In those cases you either need to set the AFMA for the distance you use it the most, or split the difference in the near and far AFMA tests and use aperture to increase the DOF and mask the error.



Yup, that has been my feeling too and I am glad I can finally find someone to agree with me 

For all the lenses I have, I have never been able to AFMA it such that it works for any subject distance.
The ones that worked for any subject distance had AFMA turned off LOL!

Yet I do recall someone on this forum had great success with it... It is puzzling. 
Perhaps some particular lens flaw happens to be compensated by AFMA perfectly.


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## East Wind Photography (Feb 21, 2013)

Generally speaking the best AFMA is the one that on average gives you the best image across the entire range subject distance range....unless the lens is really out of kilter.

That has been a long standing issue with zooms. You not only have the subject distance issue to worry about but different AFMA settings across the entire zoom range. Canon at least now with the later bodies allows for a separate AFMA for each end of the zoom range but the middle range cannot always be extrapolated linearly between the two settings.

Anyway some of the error can be made up by stopping down the lens. The best thing to do is to send the lens back to canon and have it adjusted so that the focal plain relative to AFMA is consistent from minimum to infinity focus distance when AF is activated.



PhotoCat said:


> East Wind Photography said:
> 
> 
> > Some lenses just dont focus well on a linear scale. Some need different AFMA settings focused far than focused close. To me that's a manufacturing flaw or the lens is just out of spec and needs adjusting. In those cases you either need to set the AFMA for the distance you use it the most, or split the difference in the near and far AFMA tests and use aperture to increase the DOF and mask the error.
> ...


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## digital paradise (Feb 21, 2013)

Mehmetski said:


> Repeat these steps after restarting your camera. It will give you different values.



This should apply to all MFA methods then.


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## East Wind Photography (Feb 22, 2013)

No because Dot Tune uses AF detect, others do not.



digital paradise said:


> Mehmetski said:
> 
> 
> > Repeat these steps after restarting your camera. It will give you different values.
> ...


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## digital paradise (Feb 22, 2013)

East Wind Photography said:


> No because Dot Tune uses AF detect, others do not.
> 
> 
> 
> ...



So then what difference would it make using AF detect compared to other methods. Does the power only shut of to AF detect and not to other parts of my camera?


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## East Wind Photography (Feb 22, 2013)

Other methods such as FoCal actually analyze the image using a special target to determine sharpness or resolvability at various AFMA settings. It actually takes pictures of the target to do it's analysis. It does not use AF detect at all.

They do have a beta version out which appears to do something similar as Dot Tune but I have not tried it yet.

I also have found that FoCal does not work very well with some camera lens combinations. I've used it and then done checks using a lensalign 3D target and found it to be quite off in its AFMA selection with some lenses. One of the things that it is biased towards is AF repeatability and consistency. Not necessarily the highest sharpness or resolvability. I agree that consistency is important but the goal is to provide the highest resolvability by calibrating for an in focus image. So even with FoCal you STILL have to do manual checks and compare shots to make sure it's recommended AFMA is sane. So I just do it manually now since the manual verification has to be done anyway. Manual meaning the sloped ruler and high contrast target process.



digital paradise said:


> East Wind Photography said:
> 
> 
> > No because Dot Tune uses AF detect, others do not.
> ...


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## digital paradise (Feb 24, 2013)

DotTune coming to Magic Lantern!


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## Harry Muff (Feb 24, 2013)

I can't see any mention of this on the Magic Lantern site yet.


Will the 5D2 be included?


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## Marsu42 (Feb 24, 2013)

Harry Muff said:


> I can't see any mention of this on the Magic Lantern site yet.



It's in the nightly builds (and the great new "ml junkie" ui seen in the video, btw ) - currently it works for 5d2, 5d3 but afaik will be available for all cameras that support afma - here's the link to the dev discussion: http://www.magiclantern.fm/forum/index.php?topic=4648.msg27331#msg27331


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## AlanF (Feb 25, 2013)

The ML website doesn't win prizes for user friendliness. I don't know whether the "nightly build" is in the version on the front page. So, tell us precisely what version to download of the 5D III, with the link to that version, please. Any tips for first time installers will be appreciated. 
Thanks


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## Marsu42 (Feb 25, 2013)

AlanF said:


> I don't know whether the "nightly build" is in the version on the front page. So, tell us precisely what version to download of the 5D III, with the link to that version, please.



It's simple - if you don't find it you're not supposed to use it, unlike the stable release builds the nightlies aren't even beta quality but alpha that might brick your camera. So for most people (that includes you as far as I can see) it's best to wait for the official next package with a pretty documentation and updated help files...

But if you want to try it anyway (installation is the same as the release ml, just replace autoexec.bin with a newer version): http://www.magiclantern.fm/forum/index.php?topic=3072.0

And here the changelog to see what's included in the trunk build: https://bitbucket.org/hudson/magic-lantern/commits/all/

The 5d3 might not be included in the nightlies yet, so look in the forum thread for afma support and a recently compiled version: http://www.magiclantern.fm/forum/index.php?board=34.0


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## AlanF (Feb 25, 2013)

Marsu42 said:


> AlanF said:
> 
> 
> > I don't know whether the "nightly build" is in the version on the front page. So, tell us precisely what version to download of the 5D III, with the link to that version, please.
> ...



Don't be patronising. Many of my colleagues are Nobel Laureates and they don't talk condescendingly like that.


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## TrumpetPower! (Feb 25, 2013)

AlanF said:


> Marsu42 said:
> 
> 
> > AlanF said:
> ...



Eh, I didn't take that as patronizing but rather a stern caution that "thar be dragons thar."

It's like the novice at the do-it-yourself machine shop asking where the on / off switch is on the four-ton hydraulic press. If you have to ask, it's not for you.

b&


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## Marsu42 (Feb 25, 2013)

AlanF said:


> Don't be patronising. Many of my colleagues are Nobel Laureates and they don't talk condescendingly like that.



I'm impressed :-> ... but I wasn't patronizing, actually I did some work for you and found the links you requested but am missing a "thank you" so far.

The fact that the ml website doesn't advertise dev versions is really not a bug but a feature: a simple Google search for "magic lantern nightly" turns up the link I posted as the first result, and if that's not enough then the general user crowd with a "service, please!" approach are meant to use the official releases as it needs some willingness to invest work to use bleeding edge builds.



TrumpetPower! said:


> It's like the novice at the do-it-yourself machine shop asking where the on / off switch is on the four-ton hydraulic press. If you have to ask, it's not for you.



Thanks for verifying, English is not my first language and I never quite know how it comes across. Btw unfortunately ml really has teeth as the devs have bricked several (sponsored) cameras, but they usually manage to recover them. somehow.


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## AlanF (Feb 26, 2013)

Marsu42 said:


> AlanF said:
> 
> 
> > Don't be patronising. Many of my colleagues are Nobel Laureates and they don't talk condescendingly like that.
> ...




As English is not your native language, let me explain the nuances that make the second sentence patronising. The word "pretty" is one problem. "Pretty" in that context is a pejorative word meaning that it is tarted up to appeal to the simple minded. The word "clear" would be acceptable, implying that the current description is obscure. A second is "(that includes you as far as I can see)" because it personalises the comment and also shows you making an assumption about a particular individual, which may well be unwarranted.

The first sentence may sound witty to you, but to others it smacks of arrogance. So, both sentences combined sound unpleasant to a native speaker.


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## Marsu42 (Feb 26, 2013)

AlanF said:


> The first sentence may sound witty to you, but to others it smacks of arrogance. So, both sentences combined sound unpleasant to a native speaker.



Ok, thanks for explaining - I didn't want to annoy you, why would I? I'm just trying to spread news about Magic Lantern to keep the project alive and kicking. That often means convincing people that ml is not a hack or dangerous, but in this case the the reverse: people asking for a direct download link plus a installation instruction obviously aren't familiar with ml and aren't meant to use bleeding edge releases.


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## comsense (Feb 26, 2013)

AlanF said:


> Marsu42 said:
> 
> 
> > AlanF said:
> ...


Its pretty clear that you are being oversensitive. Humor off. s/he did not mean to offend you. Just warn in a straightforward way. Also, what do you interpret your reference to Nobel Laureate colleagues as?. I have some and so would many others here. Like normal people some of the Nobel Laureates are very humble but some are incredibly arrogant. And similar are colleagues without Nobel Prize.


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## hpmuc (Feb 26, 2013)

comsense said:


> Its pretty clear that you are being oversensitive. Humor off. s/he did not mean to offend you. Just warn in a straightforward way. Also, what do you interpret your reference to Nobel Laureate colleagues as?. I have some and so would many others here. Like normal people some of the Nobel Laureates are very humble but some are incredibly arrogant. And similar are colleagues without Nobel Prize.


+1


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