# Patent: Microadjustment Automated



## Canon Rumors Guy (Jan 12, 2014)

```
<div name="googleone_share_1" style="position:relative;z-index:5;float: right; /*margin: 70px 0 0 0;*/ top:70px; right:120px; width:0;"><g:plusone size="tall" count="1" href="http://www.canonrumors.com/?p=15494"></g:plusone></div><div style="float: right; margin:0 0 70px 70px;"><a href="https://twitter.com/share" class="twitter-share-button" data-count="vertical" data-url="http://www.canonrumors.com/?p=15494">Tweet</a></div>
<p>A patent has been published outlining automatic microadjustment for Canon DSLRs and lenses. This would definitely be a handy feature going forward. Especially if you rent lenses.</p>
<ul>
<li><span>Patent Publication No. 2013-254194</span>
<ul>
<li><span>Publication date 2013.12.19</span></li>
<li><span>Filing date 2012.5.11</span></li>
</ul>
</li>
<li><span>Issues surrounding the AF adjustment</span>
<ul>
<li><span>The looseness of the phase difference AF sensor, because the AF accuracy is worse, need AF adjustment</span></li>
<li><span>It is not done correctly the AF adjustment in your environment</span></li>
<li><span>Necessary facilities such as service center</span></li>
</ul>
</li>
<li><a href="http://egami.blog.so-net.ne.jp/tag/Canon"><span>Canon</span></a><span> patents</span>
<ul>
<li><span>Automation of the AF adjustment</span></li>
<li><span>Procedure</span>
<ul>
<li><span>Let me be the difference adjusted value of the phase difference AF and contrast AF</span></li>
<li><span>To determine the reliability</span></li>
</ul>
</li>
</ul>
</li>
</ul>
<p>Source: [<a href="http://egami.blog.so-net.ne.jp/2014-01-13" target="_blank">EG</a>]</p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
```


----------



## neuroanatomist (Jan 12, 2014)

Canon Rumors said:


> Let me be the difference adjusted value of the phase difference AF and contrast AF
> To determine the reliability



Great...except that we know contrast detect AF isn't necessarily the gold standard for precision. Given the specified and observed precision of both phase and contrast AF, I really think multiple tests are required for an accurate result. It they implement this method, and it does just one contrast detect AF, I certainly won't be using it!


----------



## Jamesy (Jan 12, 2014)

And to be clear, this wouldn't make it into any existing camera bodies in the line-up, right?


----------



## mb66energy (Jan 12, 2014)

neuroanatomist said:


> Canon Rumors said:
> 
> 
> > Let me be the difference adjusted value of the phase difference AF and contrast AF
> ...



One part of the patent seems to be the reliability check of a contrast AF measurement:
"Canon patent to determine the reliability , seems to validate whether can be adjusted correctly . [...] The play of the phase difference AF if that is the cause , because there should be aging , It is what you want also a mechanism to be calibrated on a regular basis ." (via google translate)

There might be an algorithm which excludes a blue sky as welll suited CDAF object. 

Additionally I would expect a calibration of all AF points - if they differ to much this might invoke some cross checks or a new measurement procedure.


----------



## ScottyP (Jan 12, 2014)

Is this a computer translation from Japanese? The text is kind of garbled. 

I.E.

◦It is not done correctly the AF adjustment in your environment ??????
Let me be the difference adjusted value of the phase difference AF and contrast AF ??????


----------



## East Wind Photography (Jan 12, 2014)

No doubt this will be a premium feature offered only on high end models. Current model contrast AF is prett poor. However I bet the new dual pixel sensors may have improved in this area. I think it's a good move provided they fix some of the current systemic issues. No reason this can't be done in Camera.


----------



## unfocused (Jan 13, 2014)

I figured this was coming sooner or later. Manual microadjustment seems like a very primitive approach and prone to errors.


----------



## Don Haines (Jan 13, 2014)

unfocused said:


> I figured this was coming sooner or later. Manual microadjustment seems like a very primitive approach and prone to errors.


+1

This approach allows the camera to keep a running average of dozens or hundreds of shots and allows a matrix of calibrations using focal lengths and distances. Any inaccuracy of an individual measurement gets lost in a long-term average...


----------



## Mt Spokane Photography (Jan 13, 2014)

I pulled up the translation of the patent to English from the Japanese patent site. As usual, the Translation is poor, and difficult to read.

Its also written by one of those guys who, when asked what time it is, starts back with the big bang and tells of the formation of the galaxy, the movement of stars and planets, he can't just say how it works, but includes all the formulas for contrast detection, there is so much extraneous data that the real information is hard to find.

It does sound like they have all the bases covered, and understand the limitations of contrast detection.

BTW, it appears that while contrast detection on some models is unreliable, the 6D and subsequent models have been quite accurate and consistent. It makes me assume that they have improved the accuracy or discovered a flaw in the older method. If that's the case though, why haven't we seen a firmware update?

The patent does appear to all be in firmware, no physical changes to a camera, so it could be done on existent bodies, but will likely appear on new bodies first. The timing of the patent release makes it possible that we will see it on a 7D MK II and whatever new FF bodies appear.


----------



## takesome1 (Jan 13, 2014)

It was just a matter of time.

Sux to be Reikan.


----------



## Marauder (Jan 13, 2014)

Mt Spokane Photography said:


> Its also written by one of those guys who, when asked what time it is, starts back with the big bang and tells of the formation of the galaxy, the movement of stars and planets, he can't just say how it works, but includes all the formulas for contrast detection, there is so much extraneous data that the real information is hard to find.



LOL With an all-but-infinite number of "LOL's" behind it!


----------



## BL (Jan 13, 2014)

takesome1 said:


> It was just a matter of time.
> 
> Sux to be Reikan.



but very profitable while it lasted


----------



## helpful (Jan 13, 2014)

If this would be done properly, it would be the best advancement ever (that I can imagine) in the current professional workflow. I personally would use it at just about every shoot, setting up my camera and calibrating the focus adjustment to middle of the exact expected distance to my subjects, in just the same way that I set custom white balance to fit exactly the environment I am shooting. I have noticed, for example, that perfect calibration of my 400mm at 80 m does not result in perfect calibration at 25 m, and vice versa, so hence the usefulness to a professional of AF microadjustment in the field under working conditions.

Hopefully there will be an option to base the AF micro adjustment on not only the results of contrast AF comparison, but on several real automated test photos. There could be a "faster" and a "full precision" option. It would surely be possible to AF calibrate for a certain target using contrast AF comparison without taking any real photos in a matter of 1-2 seconds using Newton's method (possibly with least squares fitting) to refine the results. And with the option to use several actual photographs for exact data, it would hopefully be possible to complete the entire process in less than 5 seconds and obtain results as absolutely perfect as the maximum theoretical potential precision of the AF phase detection sensors, by centering their accuracy on dead center.


----------



## TWI by Dustin Abbott (Jan 13, 2014)

This is actually a (potentially) very exciting development. This could be a very real benefit, and I'm excited about it even though I invested in FoCal pro. Canon takes a lot of heat around here for a (perceived) lack of innovation, but this development along with DualPixel AF are actually probably some of the most innovative new features in recent years.


----------



## Woody (Jan 13, 2014)

Improvement on MagicLantern's implementation of the dot tune method? Sounds cool. Anything is welcome... as long as it's free...


----------



## Ruined (Jan 13, 2014)

Woody said:


> Improvement on MagicLantern's implementation of the dot tune method? Sounds cool. Anything is welcome... as long as it's free...



Sure, if you count buying a new camera as free


----------



## verysimplejason (Jan 13, 2014)

I just hope all of these are purely software enhancements. My 6D's doing fine most of the time...


----------



## Rienzphotoz (Jan 13, 2014)

Canon Rumors said:


> <div name=\"googleone_share_1\" style=\"position:relative;z-index:5;float: right; /*margin: 70px 0 0 0;*/ top:70px; right:120px; width:0;\"><glusone size=\"tall\" count=\"1\" href=\"http://www.canonrumors.com/?p=15494\"></glusone></div><div style=\"float: right; margin:0 0 70px 70px;\"><a href=\"https://twitter.com/share\" class=\"twitter-share-button\" data-count=\"vertical\" data-url=\"http://www.canonrumors.com/?p=15494\">Tweet</a></div>
> <p>A patent has been published outlining automatic microadjustment for Canon DSLRs and lenses. This would definitely be a handy feature going forward. Especially if you rent lenses.</p>
> <ul>
> <li><span>Patent Publication No. 2013-254194</span>
> ...


Sounds good ... any improvement in technology, that makes life a little more convenient, is always welcome ... it might not be "perfect" but its a step in the right direction and in time it will only improve.


----------



## sanj (Jan 13, 2014)

God be praised!


----------



## horshack (Jan 13, 2014)

I'd have to read through the patent to see if there are any unique elements to it but generally speaking the idea of using CDAF to auto-tune PDAF has lots of prior art online.


----------



## neuroanatomist (Jan 13, 2014)

horshack said:


> I'd have to read through the patent to see if there are any unique elements to it but generally speaking the idea of using CDAF to auto-tune PDAF has lots of prior art online.



I wonder if Canon's patent attorneys know that? I'm guessing they do...


----------



## AlanF (Jan 13, 2014)

Re accuracy of contrast AF detection. 
Dual pixel technology is a huge leap forward for this. Live view in the 70D is very fast and the contrast AF spot on. I calibrated my new 70D with both FoCal (very satisfactory) and the sloping ruler method. Live view consistently focussed on the screen with the ruler reading at the correct position. On the other hand, both in Focal and sloping ruler testing, there was the usual spread around the correct focus using phase detect.

Dual pixel technology is much to Canon's credit for both speed and accuracy of contrast detect AF. You would expect from basic statistics that the standard deviation of each reading would improve by the square root of the number of pixels employed in detection.


----------



## Dick (Jan 13, 2014)

So instead of trying to fix the AF issues, they come up with a ridiculous AFMA solution? At least for me, the AF accuracy and AFMA value depend heavily on the distance to the subject and even the lighting can affect results. Having 1 value for a lens does not fix much. Besides, a slicing golfer can surely aim off fairway at the tee, but that is a lame way to deal with the slice. A better solution is to fix the slice.


----------



## AvTvM (Jan 13, 2014)

it is the logical fix. I expect that it will only be offered on future new models [presumably all with dual pixel AF sensor] and will not come as a firmware update for any existing cameras (including 1D X and 70D). 
To me it sounds like one of the "marketing differentiation features" Canon might use to "justify" a very high 7D II launch price. 

Reliability of contrast AF for use in automated AFMA procedure is no issue in my opinion. Not on any current Canon EOS, and even less so in dual-pixel AF systems. 

Of course automated in-camera AFMA will not be performed by just pointing the camera at any kind of test scene including white wall/blue sky ... it will be a procedure were owners are given instructions regarding proper "test scene" that has enough contrast/patterns in the right places [= under all AF-fields of the camera's phase AF system]. And procedure will only be initiated and carried out, if test target offers enough contrast and structure/texture to yield proper results.


----------



## jebrady03 (Jan 13, 2014)

Dick said:


> Having 1 value for a lens does not fix much.



I didn't read the patent so I don't know for sure but, does it say it only uses one value? Or does it say multiple values are not possible?


----------



## AvTvM (Jan 13, 2014)

jebrady03 said:


> Dick said:
> 
> 
> > Having 1 value for a lens does not fix much.
> ...



1 value would only be sufficient for "on-the fly/in real time" correction applied to every shot using Phase-AF. 

Since this is not feasible [Phase-AF followed by contrast-AF, calculation and application of correction factor for each single shot] there must be a specific "AF-calibration procedure" to be started from the menu or possibly autmatically, every time a lens is mounted on a body that has not been calibrated for that body yet. And similar to current AFMA, there must be a storage matrix for each specific lens, with multiple correction factors for

a number of different subject distances at
a number of different f-stop settings in all lenses that are not fully parfocal [= majority of all Canon lenses]. 
and in case of a zoom lens, for a number of different focal lengths

If there were a matrix of these correction factors for every single AF-sensor in the camera body, the AFMA-system could even correct for (minor) misalignments of submirror/AF-lens array/AF-sensors. It could have autmatically taken care of the "left-side AF issue" in early Nikon D800 bodies ... to the point that such poblems would not even show up at all. So defintiely a highly desirable feature also from manufacturrers point of view.


----------



## Albi86 (Jan 13, 2014)

AvTvM said:


> jebrady03 said:
> 
> 
> > Dick said:
> ...



Most of it is available on Sigma lenses via the USB dock. The f-stop thing is interesting, but it could be automatic at least for Canon lenses to make up for focus shift.


----------



## polarhannes (Jan 13, 2014)

I am excited about this!

While Reikan Focal is a very nice piece software, it is really a pain to do good measurements for the 5D3 / 1DX because you have to change the AFMA values manually. This new functionality could be patched into these firmwares --> huge time saver (although I do not believe that they will provide a new firmware for these cameras)
Even if they implement the new functionality, I still see value in Focal (for example aperture sharpness test)

Sometimes when I calibrate a lens it is fine for let's say a target which is 2 meters away, but it does not really match for a target being 100m away. This method could store many many AFMA values for multiple focus distances on multiple zoom settings.
OK - not a real argument because you could do this manually as well if they implemented it. Would take even more time though. But if this was possible in an automated way I'd love it!

Nobody mentioned it - I'm quite sure they will block 3rd party lenses (eg a lens needs to identify itself correctly).
Even the Sigma USB dock does not really help. I have the 35 Art lens and you can set only 3 focus distances (~0.30 m, ~0.60m, infinity). While the focus is perfect @ f/1.4 for these distances, it is quite off between 0.60m (+14 in the USB Dock tool) and infinity (+3 in the tool). No way to correct that at the moment. Sigma still has issues here.


----------



## Don Haines (Jan 13, 2014)

HEY!
Where is the person who started the thread complaining about Canon's lack of innovation? They should have some interesting insight here


----------



## East Wind Photography (Jan 13, 2014)

Don Haines said:


> HEY!
> Where is the person who started the thread complaining about Canon's lack of innovation? They should have some interesting insight here



Is it really innovation or just stealing someone else's idea and be the first to file a patent?


----------



## Don Haines (Jan 13, 2014)

dilbert said:


> Don Haines said:
> 
> 
> > HEY!
> ...




It would certainly be a welcome feature....


----------



## Random Orbits (Jan 13, 2014)

polarhannes said:


> Nobody mentioned it - I'm quite sure they will block 3rd party lenses (eg a lens needs to identify itself correctly).
> Even the Sigma USB dock does not really help. I have the 35 Art lens and you can set only 3 focus distances (~0.30 m, ~0.60m, infinity). While the focus is perfect @ f/1.4 for these distances, it is quite off between 0.60m (+14 in the USB Dock tool) and infinity (+3 in the tool). No way to correct that at the moment. Sigma still has issues here.



+1. I wouldn't be surprised if a change like this would lead to compatibility issues with 3rd party lenses. It would be one thing if 3rd party lenses would function as they had before and the canon lenses gained increased accuracy, etc, but it would be another if the 3rd party lenses are bricked. As much as people complain about Canon bodies not accepting 3rd party batteries after a firmware update, not being able to use 3rd party lenses would be much worse. Not so much an issue for MF lenses only (i.e. Samyang), but it would be a large threat to Sigma/Tamron. Even if Sigma were able to provide updated firmware after a few months, the damage will be done. People may blame Canon for breaking compatibility with 3rd party lenses, but a lot fewer people would be willing to take the risk of buying 3rd party lenses again...


----------



## Dick (Jan 13, 2014)

Albi86 said:


> AvTvM said:
> 
> 
> > jebrady03 said:
> ...



The USB dock is useless. For the 35mm lens you, for example, can only give 1 value for everything that is further than 70 cm away? Correct? At least that is what I was told the other day when I was about to buy a dock. So sensible settings are only available, if you shoot nearby subjects. And for that, I'm fine with my +3. The focus gets messed up when people stand 5 m away from me, whereas for 2 m the +3 still works nicely.


----------



## neuroanatomist (Jan 13, 2014)

AlanF said:


> Dual pixel technology is much to Canon's credit for both speed and accuracy of contrast detect AF. You would expect from basic statistics that the standard deviation of each reading would improve by the square root of the number of pixels employed in detection.



My understanding is that DPAF is a _phase_ detect AF system. If the DPAF is used to 'get close' then contrast detect is used for final focus, DPAF is speeding the process up but not making it more accurate. As Mt. Spokane pointed out above, Canon substantially increased the precision of contrast detect AF in recent bodies, and that likely accounts for the increased accuracy of CDAF on the 70D.


----------



## AvTvM (Jan 13, 2014)

neuroanatomist said:


> My understanding is that DPAF is a _phase_ detect AF system. If the DPAF is used to 'get close' then contrast detect is used for final focus, DPAF is speeding the process up but not making it more accurate. As Mt. Spokane pointed out above, Canon substantially increased the precision of contrast detect AF in recent bodies, and that likely accounts for the increased accuracy of CDAF on the 70D.



yes. In the 70D there is a total of 3 AF-systems at work:
A) "regular" DSLR Phase-detect AF [via mirror/submirror/AF-sensor at bottom of mirrorbox) 
B) contrast-detect AF - working from sensor feed
C) on-sensor dual-pixel phase-detect AF 
combination of B+C = AF-system used in LiveView (and video) only

AFMA correction factors are needed for and work on regular Phase-Detect-AF (A) only.
Automatic calibration of A) could be done using values of B (CD-AF) only or combination of B+C (CD-AF plus on-sensor PD-AF). 

The whole AFMA issue will be mute, as soon as all decent cameras will be mirrorless.   

MILCs only need one or at most 2 AF-systems ... contrast-detect [speed is solely dependent on porocessing power and algorithms available] and/or on-sensor phase-detect. ;-)


----------



## polarhannes (Jan 13, 2014)

Dick said:


> Albi86 said:
> 
> 
> > AvTvM said:
> ...



Yes, correct. Only 1 value for objects being further away than 0.60m (the infinity value).
It focuses perfectly for 0.30m, 0.60m and for infinity (just as configured with the USB dock), but the focus is really off in between of 0.60m and infinity. Don't know what they were thinking when they invented the USB dock, but 0.30m , 0.60m and infinity do not sound like reasonable distances for calibrating a 35mm lens.


----------



## K-amps (Jan 13, 2014)

Is this why they crippled Reiken on the 5diii? Canon was not supporting full auto mode last year? If so, could this be available on the 5d3 as a firmware upgrade?


----------



## mackguyver (Jan 13, 2014)

K-amps said:


> Is this why they crippled Reiken on the 5diii? Canon was not supporting full auto mode last year? If so, could this be available on the 5d3 as a firmware upgrade?


They brought back support (via the software developer's kit [SDK]) for the 6D (and 70D, I believe), but not the 5DIII and 1DX. No one really seems to know why they have done this, but it seems to be a differentiator between pro/sumer & consumer lines. Perhaps this patent is the reason, because it makes no sense otherwise. The very people who want to do AFMA are most likely 1DX & 5DIII users...


----------



## ashmadux (Jan 13, 2014)

this would be the most greatest thing ever.

Ill do whatever it takes to get the job done, but I truly despise just setting up fOcal- distances of 13 feet away from target, have to purchase long usb cords, need great amounts of light, etc. Its a pain in the ass (sometimes). I went full frame in November, and i have yet to be able to enjoy its benefits because of the ludicrous amount of time and particular setup needed to adjust lenses. So for my Ive been so disappointing by the lack of sharpness, overall image quality vs my crop cam, etc. 

however canon can make this easier, would get my money. The current situation is truly horrible for pros and consumes alike spending thousands on gear that may or may not work well together.


----------



## neuroanatomist (Jan 13, 2014)

AvTvM said:


> MILCs only need one or at most 2 AF-systems ... contrast-detect [*speed is solely dependent on porocessing power and algorithms available]* and/or on-sensor phase-detect.



Not quite. One big difference between phase detect AF (PDAF) and contrast detect AF (CDAF) is that the phase difference provides data on both the magnitude of the change needed to achieve focus _and the direction of the change_, whereas CDAF does not provide directional information. So, for CDAF to work, it has to pick a direction and start to move the focusing elements, then determine whether the image becomes more or less focused - there's a 50/50 chance of getting it right (perhaps higher if the system guesses based on where the focusing group starts, e.g. if near the MFD, guess that focus needs to move away not toward, but it's still a guess). A big boost in speed when supplementing CDAF with on-sensor PDAF is that the focus starts moving in the right direction first, every time.


----------



## jrista (Jan 13, 2014)

horshack said:


> I'd have to read through the patent to see if there are any unique elements to it but generally speaking the idea of using CDAF to auto-tune PDAF has lots of prior art online.



It really depends on the implementation. Use of CDAF to tune PDAF has been done, but patents are more about the specifics of the implementation as well as the description of design that employ a certain practice. Overly broad and vague patents, like Apples bogus claim to patent of "rounded corner icons", are bound to fail due to prior art. If Canon has a very specific, technical implementation that relies on some very specific aspect of their technology, such as DPAF, then it is possible it would not be rendered invalid by prior art.


----------



## Don Haines (Jan 13, 2014)

jrista said:


> horshack said:
> 
> 
> > I'd have to read through the patent to see if there are any unique elements to it but generally speaking the idea of using CDAF to auto-tune PDAF has lots of prior art online.
> ...



Exactly!

The concept might be public use, but a specific algorithm could be patented... In fact, they would want to patent it to prevent someone else from copying their algorithm, patenting it, and suing Canon...


----------



## hpjfromdk (Jan 13, 2014)

For those interested, the English version of JP2013254194, namely patent app US20120300116 was issued back in Nov 29 2012, can be found here: 

http://www.freepatentsonline.com/20120300116.pdf

It's probably a little easier to read than the JPO machine translations..


----------



## AvTvM (Jan 13, 2014)

neuroanatomist said:


> AvTvM said:
> 
> 
> > MILCs only need one or at most 2 AF-systems ... contrast-detect [*speed is solely dependent on porocessing power and algorithms available]* and/or on-sensor phase-detect.
> ...



Yes, i agree on the advantages of combining on-sensor pdaf (=no mirrors onvolved) plus cd-af .. As this hybrid combo combines the relative strengths of both concepts.

But ... CD-AF finds its target without pdaf as well. As proven in gazillions of smartphones and digital cameras of all sorts. And if there is enough cpu power snd smart algorithms it cokld be as fast as you want it. 100 fps full tracking at any point of the imaging surface. Thats why i believe that at the end of the day we will habe solid state cameras with cd-af only. Mechanics and pdaf - even the on-sensor variations - will disappear. 

Until then i would be happy to get a 36x24 sensored camera with only 2 instead of 3 separate af systems.


----------



## neuroanatomist (Jan 13, 2014)

AvTvM said:


> But... CD-AF finds its target without pdaf as well. As proven in gazillions of smartphones and digital cameras of all sorts. And if there is enough cpu power snd smart algorithms it cokld be as fast as you want it.



Yes, gazillions of smartphones and digital cameras that focus very slowly. CDAF might be "fast enough" but PDAF or a hybrid system will always be just a little bit faster, because the direction of movement is known at the outset.


----------



## Albi86 (Jan 13, 2014)

neuroanatomist said:


> AvTvM said:
> 
> 
> > But... CD-AF finds its target without pdaf as well. As proven in gazillions of smartphones and digital cameras of all sorts. And if there is enough cpu power snd smart algorithms it cokld be as fast as you want it.
> ...



I doubt the day is far away when such difference will become field irrelevant, however relatively big it might be.

One point, however, that maybe hasn't been considered yet: what about the lenses? The problem, if I understand correctly, might arise with primes that don't have high contrast wide open. We might need to get to a point where the average lens performs wide open like the latest Zeiss or Sigma to make contrast AF reliable.


----------



## jrista (Jan 13, 2014)

neuroanatomist said:


> AvTvM said:
> 
> 
> > MILCs only need one or at most 2 AF-systems ... contrast-detect [*speed is solely dependent on porocessing power and algorithms available]* and/or on-sensor phase-detect.
> ...



I don't think CDAF's lack of predetermine directionality would matter in this case. All that is necessary is for CDAF to achieve focus as a reference point. Once a reference point is attained (and CDAF CAN indeed achieve very good focus once it's done going through all its gyrations), you save the focus group position of the lens, then all you need to do is test PDAF at a distribution of AFMA settings until you zero in on the one that most closely matches the CDAF position, and ensure that setting produces repeatable results.


----------



## horshack (Jan 14, 2014)

jrista said:


> I don't think CDAF's lack of predetermine directionality would matter in this case. All that is necessary is for CDAF to achieve focus as a reference point. Once a reference point is attained (and CDAF CAN indeed achieve very good focus once it's done going through all its gyrations), you save the focus group position of the lens, then all you need to do is test PDAF at a distribution of AFMA settings until you zero in on the one that most closely matches the CDAF position, and ensure that setting produces repeatable results.



The PDAF cycles aren't required. Once CDAF has found the optimum contrast point, the AFMA value can be determined almost instantly by evaluating the phase differential and then applying the appropriate AFMA adjust value to bring that differential to its minimum. This is one method outlined in Canon's patent.


----------



## neuroanatomist (Jan 14, 2014)

jrista said:


> neuroanatomist said:
> 
> 
> > AvTvM said:
> ...



No, it doesn't matter for AFMA. But routine focusing during everyday shooting was the subject under discussion (albeit one tangential to the topic).


----------



## jrista (Jan 14, 2014)

horshack said:


> jrista said:
> 
> 
> > I don't think CDAF's lack of predetermine directionality would matter in this case. All that is necessary is for CDAF to achieve focus as a reference point. Once a reference point is attained (and CDAF CAN indeed achieve very good focus once it's done going through all its gyrations), you save the focus group position of the lens, then all you need to do is test PDAF at a distribution of AFMA settings until you zero in on the one that most closely matches the CDAF position, and ensure that setting produces repeatable results.
> ...



Well there you go then. Even better. Wasn't there a thread recently about the lack of Canon innovation? I think this patent would debunk that notion right off.


----------



## scottkinfw (Jan 14, 2014)

Exactly (and I'm not a golfer)



Dick said:


> So instead of trying to fix the AF issues, they come up with a ridiculous AFMA solution? At least for me, the AF accuracy and AFMA value depend heavily on the distance to the subject and even the lighting can affect results. Having 1 value for a lens does not fix much. Besides, a slicing golfer can surely aim off fairway at the tee, but that is a lame way to deal with the slice. A better solution is to fix the slice.


----------



## neuroanatomist (Jan 14, 2014)

scottkinfw said:


> Exactly (and I'm not a golfer)
> 
> 
> 
> ...



I'm sure Canon could 'fix the slice' i.e. tighten manufacturing tolerances sufficiently to obviate the need for AFMA. But if they did, you'd need Tiger Woods' income to buy those lenses. 

Many other 'issues' that plague lenses, like focus breathing, repeatability of setting a focus distance, etc., are correctable. Canon has done so for their Cinema lenses (which don't even have AF) - check the price tag of those when wishing for Canon to 'fix the AF issues.'


----------



## AvTvM (Jan 14, 2014)

jrista said:


> Well there you go then. Even better. Wasn't there a thread recently about the lack of Canon innovation? I think this patent would debunk that notion right off.



Well ... n automated in-camera AF-calibration system certainly is no huge "innovation".
Basically it is just a necessary little service fix to avoid problems stemming from manufacturing tolerances in camera and lens assemblies. The very idea to include a storage for AF-system correction factors in a camera [AFMA] and to automaticallycalibrate the phase-AF system with a second AF-system present in all current Canon digital cameras, is not very innovative per se. Even more so, when out of camera software to this purpose already has been invented. ANd notwithstanding the engineering finesse it may take to implement in camera.  

Anway, AFMA is a solution to an "intermediate problem" that will automatically disappear, as soon as mirrors in cameras' lightpath and off-sensor (phase) AF-systems will be abolished altogether. 

I'd rather Canon to focus their innovative powers towards a really good, FAST AND PRECISE FOCUSING, MOTION-TRACKING-CAPABLE AF-system in a 35-sensored solid-state camera. 8)


----------



## Zv (Jan 14, 2014)

Does this mean no more trying to line up targets? Or is it just that the software to determine if the lens is out of whack is now installed in the cameras firmware as opposed to your laptop? And would it set just one value or more? 

Would be awesome if it could learn and adjust as you shoot.


----------



## madmailman (Jan 14, 2014)

Would the next "logical" step be using CDAF on one of the focus points and then PDAF takes over in AI-Servo (or video) mode to enable focus anywhere on the sensor (with a STM lens no doubt)? A combo AF system for AI-servo mode sounds like it could be very useful to a lot of people. No?


----------



## rs (Jan 14, 2014)

Zv said:


> Does this mean no more trying to line up targets? Or is it just that the software to determine if the lens is out of whack is now installed in the cameras firmware as opposed to your laptop? And would it set just one value or more?
> 
> Would be awesome if it could learn and adjust as you shoot.


Maybe I'm missing something, but I'd have thought that as there's an inevitable time delay between AF chip based PDAF and sensor based CDAF (the mirror has to move between these two states), the only sensible way to accomplish a sync/calibration between the two is to have the camera fixed and pointing at a suitable target. So I'm guessing it'll just be a glorified in-camera version of plugging your laptop in and paying for suitable software.

Learning as you shoot could be the next logical step, but with some potential issues. The camera knows which AF point(s) it used, and which one locked on the best, so it knows which part of the image should have the greatest micro contrast. A simple analysis of the photos taken could be used to provide feedback of how well it performs, and make a best guess at how much to tweak, even if it doesn't know which direction to tweak it in (although if it records how far out each PDAF point was, it could use a best fit of contrast in all those areas to speed things up). After a handful of photos, a minor AF issue could be completely resolved. Over time it could also be used to learn different zoom settings, apertures and focus distances this way. If it's out by more than a certain tolerance, it would take too long and cause too many misfocused shots - not great if you depend on the camera/lens to deliver the goods there and then. In that case it could suggest you sort it out with a full on calibration as above. It could also learn on the fly about the way the photographers subjects move to predict AF better, and to learn about the photographers technique. The focus and recompose technique will completely throw that system though...


----------



## rs (Jan 14, 2014)

madmailman said:


> Would the next "logical" step be using CDAF on one of the focus points and then PDAF takes over in AI-Servo (or video) mode to enable focus anywhere on the sensor (with a STM lens no doubt)? A combo AF system for AI-servo mode sounds like it could be very useful to a lot of people. No?


If you're using the optical viewfinder for stills, sensor based CDAF can't be used as the mirror blocks all light to the sensor except during the very brief moment the photo is taken. An AF chip based CDAF would suffer from the same misalignment issues as AF chip based PDAF, so no gains in doing it that way...


----------



## epsiloneri (Jan 15, 2014)

Hm, this sounds very much like what I suggested in this forum, 3 years ago:



epsiloneri said:


> 1) AF focus on a target, say a properly aligned focus target. The camera registers what it thinks is the best focus.
> 2) Without moving the camera or the focus tagert, go to 10x live view and manually focus to what you think is the best focus, push a button or something for the camera to register what your preferred focus is.
> 3) The camera makes use of info from 1 and 2 to compute MA.
> [...]
> Alternatively, one could let the camera itself compare the AF between the AF sensors and the live view contrast AF, and compute MA under the assumption that live view AF is more accurate. That would be even simpler, and according to my experience, live view contrast AF is nearly always accurate (but slower). Contrast AF is not affected by front/back focus issues, since it uses the actual detected image for AF, so it would be perfect to correct for AF sensor MA. I can imagine setting up the camera on a tripod and align it to a focus target, select "calibrate AF" from a camera menu, and then let the camera automatically cycle through 10 AF measurement cycles (say), computing the best MA. Why not, Canon?



I'm glad Canon listened  I hope this makes it into firmware at some point...


----------



## Marsu42 (Jan 15, 2014)

Canon Rumors said:


> Automation of the AF adjustment



Magic Lantern dot_tune module does this, cost: zero, availability: now ... there may be concerns over precisions and whatnow, but I'm positive it's quick & worth a shot, esp. over manual attempts. Works for me.


----------



## TWI by Dustin Abbott (Jan 15, 2014)

Marsu42 said:


> Canon Rumors said:
> 
> 
> > Automation of the AF adjustment
> ...



Let's hope this isn't the last of the Magic Lantern advances that makes it into official Canon firmware. Canon should be thankful for the ML team, as they give not only some great advances/flexibility to Canon cameras, they also give the "tuning/customizing" crowd something real and tangible to do to tweak their cameras in a non-destructive way.


----------



## Albi86 (Jan 19, 2014)

TWI by Dustin Abbott said:


> Marsu42 said:
> 
> 
> > Canon Rumors said:
> ...



+1

Hopefully one day Canikon will understand the 3rd parties ENRICH their systems, not THREATEN them. If one between Canon and Nikon fully supported Sigma and Tamron for the AF and compatibility, people might switch just because of that.


----------



## Marsu42 (Jan 19, 2014)

Albi86 said:


> If one between Canon and Nikon fully supported Sigma and Tamron for the AF and compatibility, people might switch just because of that.



Exactly, that's why they won't do it  ... they care about profits, not about a user base buying just a body and then Sigma/Tamron lenses, Yongnuo flashes and 3rd party batteries. In the net profit, creating FUD is a sound decision unless people switch because they don't trust the brand and system anymore ... but Canon is far from that stage, despite the latest 3rd party battery tricks.

If you think about it from this perspective, ML is a thorn in their side, no way of telling how many people are happy with a Rebel and ML feature usability enhancements that would have bought a xxd or xd otherwise...


----------



## Don Haines (Jan 19, 2014)

Marsu42 said:


> Albi86 said:
> 
> 
> > If one between Canon and Nikon fully supported Sigma and Tamron for the AF and compatibility, people might switch just because of that.
> ...


The vast majority of people shoot with low end cameras, and the vast majority of those will not use Magic Lantern. They buy a basic camera with a kit lens ( sometimes two) and that's it..... The people who modify cameras are such a small percentage in the grand scheme of things that it just does not matter....

We members of this forum represent the fanatics.... There are 5825 members of this forum.... Canon sold about 10 million cameras last year.....the estimates are that there are at least 50 million people actively shooting with canon cameras.... That makes us about a tenth of a percent of the audience, and if you figure it by active members, we are less than a hundredth of a percent of the market.... A $20 off sale on T3's will probably have more impact than a concerted effort from us....

Somehow, I really don't think Canon is worried about magic lantern or our opinions....


----------



## Marsu42 (Jan 19, 2014)

Don Haines said:


> Somehow, I really don't think Canon is worried about magic lantern or our opinions....



Absolutely, and that's fortunate for the ML guys as Canon has no financial loss - but for the enthusiast segment, I have to say I wouldn't have bought the 6d if ML wouldn't have an auto iso that allows faster shutter speeds in Av than the idiotic Canon defaults, I'm using this for 2/3 of my shots. Canon tried to differentiate cameras with this firmware cripple trick, as you can set faster speeds on 5d3 and esp. 1dx - but with ML, their marketing trick is worthless.


----------



## neuroanatomist (Jan 19, 2014)

Don Haines said:


> I really don't think Canon is worried about magic lantern or our opinions....



Our opinions clearly matter to Canon, that's why after 5 years of complaints that their sensors have two stops less DR at low ISO, they've finally released a new sensor with dramatically better low ISO DR. 

Oh wait, they haven't done that. I guess you're right.


----------



## Marsu42 (Jan 19, 2014)

neuroanatomist said:


> Oh wait, they haven't done that. I guess you're right.



But maybe it's in the queue? Looking at the fw updates, they obviously do have an ear to the ground, for example auto iso on 7d 2.0 and ec in m plus faster min. av shutter on 1dx 2.0 ... but of course these things take their programers a day's work unlike exchanging sensor tech or licensing it.


----------



## neuroanatomist (Jan 19, 2014)

Marsu42 said:


> But maybe it's in the queue?



Could be. I bet we'll see more MP before more DR.


----------



## jrista (Jan 19, 2014)

Marsu42 said:


> Canon Rumors said:
> 
> 
> > Automation of the AF adjustment
> ...



The dot tune approach is not accurate. I've tried using it on multiple occasions with all of my lenses in the 7D, and dot tune always results in incorrect AFMA (sometimes, wildly incorrect). Manually tuning and/or Focal are the best ways to tune so far. Automatic AFMA with CDAF+PDAF is probably the only way to really generate accurate AFMA settings.


----------



## neuroanatomist (Jan 19, 2014)

jrista said:


> The dot tune approach is not accurate.



Agreed. I've tried it on my 1D X (the 'original', obviously not the ML implementation), and the results were unreliable. OTOH, manual AFMA with a LensAlign Pro and FoCal give accurate results that are equivalent to each other.


----------

