# Microadjustment



## aldvan (Aug 28, 2011)

I just got back from Canon Service my 1Ds Mk3 for a focal plane adjustment.
After that, as I use to do, I made a microadjustment of all my lenses.
During the classical 'moirÃ©' procedure, I needed adjustment in a +3/+8 range.
For the first time, after the MA, I verified pedantically in the real world the results and I found that the microadjusted focus is ok in case of Automatic AF selection, but, if I select the AF central point, that is my usual modus operandi, the microadjusted focus is slightly worse than the plain one.
Any interpretation?
TIA
Aldo


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## neuroanatomist (Aug 28, 2011)

Did you use the central AF point for the microadjustment calibration? How did you align your moirÃ©-producing pattern to the camera (orthogonal alignment is important for an accurate calibration)?


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## Mt Spokane Photography (Aug 28, 2011)

The moire pattern has not been reliable for me, so I've stopped using it. Its difficult to intrepret. I use the center point to micro adjust. If the other points are then significantly off, then the body may need some repair. 

There will always be some inaccuracy in both the body and the lenses, nothing is perfect. Its just when it becomes a significant issue that service is needed.


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## neuroanatomist (Aug 28, 2011)

FWIW, I don't find the classical 'moirÃ©' procedure to be all that accurate. I find that I can move the camera back and forth a fair distance without seeing any observable difference in the moirÃ© pattern on the LCD. Personally, I use a LensAlign Pro for my calibrations.


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## Viggo (Aug 28, 2011)

I also used to use that. But for my newly bought (second copy, missed it too much) 85 L II, I didn't do the moirÃ© thing. I just shot at a distance quite far from mfd, something within 15-30 meters, and just tried several times, and adjusted (shot wide open). This method of real life examples straight away worked much better then I would have thought, but it makes sense. Just find something that's easy to focus on and take shots at 0, +10 and -10 to see where it get's way worse, then half your way through it.


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## Mt Spokane Photography (Aug 28, 2011)

Viggo said:


> I also used to use that. But for my newly bought (second copy, missed it too much) 85 L II, I didn't do the moirÃ© thing. I just shot at a distance quite far from mfd, something within 15-30 meters, and just tried several times, and adjusted (shot wide open). This method of real life examples straight away worked much better then I would have thought, but it makes sense. Just find something that's easy to focus on and take shots at 0, +10 and -10 to see where it get's way worse, then half your way through it.



The problem with shooting at a distance is that the depth of field increases, so you can't tell if the lens is front or back focusing. I keep a reasonably short distance to the target, depending on focal length so that I have a shallow depth of field. A shallow depth of field lets one set MA very accurately, I can usually discern a difference of +/- 1.


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## aldvan (Aug 28, 2011)

@neuroanatomist: yes, I used the central AF point for MA, since this is my usual focusing system.
@viggo: after using the moirÃ© system, I started just with the method you proposed, finding the best result at 0 adjustment...


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## neuroanatomist (Aug 28, 2011)

Normally, you should test at 25-50x the focal length. So the 85L, for example, should be tested at 2.125-4.25 m, not 15-30 m, where as Mt. Spokane pointed out, the greater distance makes DoF more than deep enough to mask focus errors (again with the 85L as example, 85mm f/1.2 at 30 m means a DoF of nearly 10 m deep!!).


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## Mt Spokane Photography (Aug 28, 2011)

aldvan said:


> @neuroanatomist: yes, I used the central AF point for MA, since this is my usual focusing system.
> @viggo: after using the moirÃ© system, I started just with the method you proposed, finding the best result at 0 adjustment...



At 30 meters, almost everything will be in focus due to the large depth of field. Be sure to check at a close distance, say 2 meters wide open and see if its still accurate.


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## Gothmoth (Aug 31, 2011)

> Be sure to check at a close distance, say 2 meters wide open and see if its still accurate



as usual such general statements are wrong.
i would not test my 300mm or 400mm lenses at 2m. 

i donÂ´t even care if i have a back or front focus at such close distance with a 400mm tele.


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## neuroanatomist (Aug 31, 2011)

Gothmoth said:


> > Be sure to check at a close distance, say 2 meters wide open and see if its still accurate
> 
> 
> 
> ...



I would assume that Mt. Spokane was referring to the example raised by Viggo, namely the 85L. For that lens, a distance of 2 m is ok (85mm x 25 = 2.125 m).

Your 400mm tele should be tested at ~10 m. The distance used is really a compromise - for some lenses which exhibit a mild focus shift, you might get a different result testing at the minimum focus distance (MFD) vs. testing at a long distance (assuming you had a method that could accurately test with the deep DoF at a long distance). But, AF errors will be most evident at the MFD, where the DoF is shallowest.


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## Mt Spokane Photography (Aug 31, 2011)

Gothmoth said:


> > Be sure to check at a close distance, say 2 meters wide open and see if its still accurate
> 
> 
> 
> ...



We are talking his 85mm f/1.2 lens, not a 400mm lens, and advice given for a 85mm lens is not applicable to a 400mm lens.


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## Viggo (Aug 31, 2011)

Mt Spokane: 

I assume you have never tried a 85 L II? I shot across the yard outside, and aimed at a cars license plate a,d it was only sharp focus on the plate, and widway up the hood and maybe 0,5 meters infront of the car, that is much easier to determine wheter or not if the focus is hitting straight than at MFD. Because at mfd the veeery tiny back or front focus won't show, but it makes a HUGE difference when you put in some distance, trust me. I had a 300mm f2,8 L IS that was bang on at mfd and 40 meters off at 200 meters. And that is very common with lenses. 

The trick is to shoot at such a distance that let's you see where the focus really hits, and not so long you go past hyperfocal and everything is in focus as you say.

Besides, focusing errors at 90cm at 1,2 is MUCH more common, and it becomes very difficult to see if the lens misses or if the focus misses in camera. I've done this with perfect results for as long as microadjustment have existed, so please try before you bluntly assume something.


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## neuroanatomist (Aug 31, 2011)

Viggo said:


> Mt Spokane:
> 
> I assume you have never tried a 85 L II?



Sounds like a blunt assumption to me...



Viggo said:


> I shot across the yard outside, and aimed at a cars license plate a,d it was only sharp focus on the plate, and widway up the hood and maybe 0,5 meters infront of the car, that is much easier to determine wheter or not if the focus is hitting straight than at MFD. Because at mfd the veeery tiny back or front focus won't show, but it makes a HUGE difference when you put in some distance, trust me. I had a 300mm f2,8 L IS that was bang on at mfd and 40 meters off at 200 meters. And that is very common with lenses.
> 
> The trick is to shoot at such a distance that let's you see where the focus really hits, and not so long you go past hyperfocal and everything is in focus as you say.



Ok, so your subject is sized proportionally to your DoF, so that can work. It all depends on _how_ you test. With a calibration tool such as the LensAlign, resolving that 'veeery tiny back or front focus' is quite easy to do, because unlike a car parked across your yard, that tool is designed to do just that. 

Here's what it looks like in use, and you can see that any front or back focus would be immediately obvious - the thinner the DoF, the better. 







In fact, 2 m on an 85L is no where near the MFD (which is actually slightly less than 1 m). IMO, using a tool designed for the job is better, because it eliminates some of the variables that could otherwise cause problems. Are you orthogonal to the license plate? Is the plate itself providing adequate contrast? Is the AF system really even focusing on the plate? That last question is important, because at the distances I believe you're talking about, a standard sized license plate will cover only a small fraction of the AF point on the sensor (which is a larger area than suggested by the little box in the viewfinder) - so, you may intend to focus on the license plate, but your camera's AF system doesn't know that, and will just grab the highest contrast feature at the proper orientation within the sensitive area, which might be the bumper...or the shadow of the bumper on the ground several cm in front of the car.

Probably most importantly, when you shoot with the 85L, are most of your shots taken from a distance similar to 'across the yard'? Personally, most of my shots with my 85L are portraits taken at a distance of 2-3 m. So, having spot-on AF at a distance of 20 m, even if that is achieved, is not very helpful if it's not applicable at the distances where I most often use the lens...


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## Viggo (Aug 31, 2011)

Wow, this is beginning to become a discussion I'm not going to bother bickering about. First off, When you use 1dmkIV the focusing point is so large that it covers at least too much of those fine lines on a chart to be even remotley accurate. Second of all, it must be at a larger distance to see what happens. I have countless times been really upset when I have fiddled around with charts and moirÃ© patterins at 1m or 2m and getting it PERFECT, then turn around and shot a black and white super-high contrast road sign outside, perfectly level and everything (I'm not a noob at this) and it's waaay off, I keep shooting that sign and also the bottom of the sign as that is much easier to see where the dof hit the asphalt, and clearly see the dof moving back and forth, then I just leave it where it hits sharp (which is usually a whole other MA setting then before) and go back to the moirÃ© pattern, or test chart and find that it hits EXACTLY the same spot as the first time, only now it's a very different MA adjustement, and what do you know, now it works at a distance too. Adjusting at mfd will never be accurate enough. At Northernlight they suggest you use at LEAST 50 times the focal to adjust.

So whatever works for you, fine! But do not tell me that my method doesn't work, and for me it works much better, because aiming in between very long and very short distance to subject I get sharp POF on ALL distances. I did so with these lenses: ef 14L II, 24 1,4LII, 50L, 85L (twice) 70-200 II, 300 f2,8 L IS. That's the way it was and always will be.


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## aldvan (Aug 31, 2011)

Please forgive me for starting a discussion that is becoming quite harsh...
By the way, although the idea to microadjust by a simple tool intrigued me at first, I'm convincing my self that the procedure suggested by Canon itself should be closer to the needs of the real world.
Rather, there are some points that I overlooked and that are very important.
The first one, as others already pointed in their post, is the perfect parallelism between camera and target (and this could be a point in favor of Lensalign).
The second one, that I forgot to do until now, is TO TURN OFF the image stabilizer...
I'll repeat the procedure next week end...


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## Viggo (Aug 31, 2011)

You should also consider this one. I tried it and it made sense of the adjustments I already had done. (tried one we had in our camera-store were I work). It's ridicolously expensive so might want to pitch in with a few buddies ;oD

http://spyder.datacolor.com/product-cb-spyderlenscal.php


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## neuroanatomist (Aug 31, 2011)

Viggo said:


> So whatever works for you, fine! But do not tell me that my method doesn't work, and for me it works much better, because aiming in between very long and very short distance to subject I get sharp POF on ALL distances. I did so with these lenses: ef 14L II, 24 1,4LII, 50L, 85L (twice) 70-200 II, 300 f2,8 L IS. That's the way it was and always will be.



Agreed. I've gotten excellent results with the LensAlign Pro and a much longer list of lenses than yours, and it works for me. If your method works for you, keep doing it!

I won't quibble, but I will correct a few inaccuracies:



Viggo said:


> Adjusting at mfd will never be accurate enough. At Northernlight they suggest you use at LEAST 50 times the focal to adjust.



Once again, not MFD. The usual recommendation is 25-50x the focal length of the lens - frequently qualified by the advice to test at the most relevant/common subject distance for your typical subject(s). Granted, that's not always easy because most people shoot more than one type of subject with a given lens. 



Viggo said:


> I have fiddled around with charts and moirÃ© patterins at 1m or 2m



The problem there is not the distance, it's the other part of the statement - fiddling around with charts and moirÃ© patterns. Printed charts don't cut it, and moirÃ© patterns have too much play (little to no discernable difference with a pretty large degree of axial movement) and problems with alignment. You need to use the right tool for the job. If your auto mechanic 'fiddled around' with a crescent wrench when working on your car's powertrain, instead of properly tightening the bolts with a torque wrench, you'd have maintenance issues down the line.

Your subsequent statement about the SpyderLensCal, "_I tried it and it made sense of the adjustments I already had done,_" is totally consistent with what I'm saying here - when you use the right tool, you get accurate results.



Viggo said:


> First off, When you use 1dmkIV the focusing point is so large that it covers at least too much of those fine lines on a chart to be even remotley accurate.



With this and other, similar tools, you're not focusing on the ruler with the DoF scale - the ruler is at an angle to the vertical so the scale has depth, and your focus target is a larger square with a contrast scheme optimized to activate any AF sensor point geometry (horizontal- or vertical-line, cross-type, or diagonal cross-type) that is aligned to be parallel to the image plane (and thus orthogonal to the AF sensor).






The SpyderLensCal you linked to is constructed in the same way (but it seems to lack a feature to facilitate parallel alignment of the camera with the focusing target.





aldvan said:


> Rather, there are some points that I overlooked and that are very important....I'll repeat the procedure next week end...



One point that has not come up, but which is quite important, is what autofocus microadjustment really does. What AFMA does is correct for systematic error in the AF system, specific to manufacturing tolerances in cameras and lenses. It corrects for bias in the AF system, or put another way, it improves the accuracy of the AF system. The terms accuracy and precision are sometimes (improperly) used interchangeably - accuracy is 'closeness to true' whereas precision is repeatability. Here's a diagrammatic example:






AFMA corrects for accuracy but does nothing for precision. Chuck Westfall has told me that, "_The AF precision for the standard precision sensors is within the depth of focus for the maximum aperture of the lens, while the AF precision for the high precision sensors is within 1/2 or 1/3 the depth of focus for the maximum aperture of the lens, depending on the camera model under discussion._" Note that depth of focus is measured at the image plane of the sensor, and is different from (but affected by the same parameters as) the depth of field. I interpret that to mean that although the precision is specified, for example with the f/2.8 sensor all the shots will be focused within a region that is 1/3 of the depth of focus deep for that lens' maximum aperture, focusing could still be inaccurate (i.e. it would look like case C above).

AFMA moves the center point - the 'average' focal plane of multiple measurements. But it's important to remember that precision plays a role, so if you test your AF system with just one or a couple of tries, random chance says your test won't be 'spot on' due to imprecision. So, when testing AF performance, you need to perform multiple tests for a given lens, and fewer tests would be needed for an f/2.8 or faster lens due to the higher precision. I suspect this is what's behind Canon's statement that AFMA can prevent correct focusing - if you base an adjustment on one or two test shots, and those shots were relatively far off the correct focal plane, then on average most of your subsequent shots will miss focus. 

Bottom line - no camera will produce a perfectly focused image every time at every distance, period. No adjustment procedure will change that. What a proper AFMA can do is increase the percentage shots that are correctly focused.


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## neuroanatomist (Aug 31, 2011)

As a side note, some time back epsiloneri posted a very nice method for quantitatively determining the best AFMA setting. It's something I plan to try when I get a chunk of free time.


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## Viggo (Aug 31, 2011)

Well, fair enough, it seems that we actually agree on most things, and the rest I'm not going to discuss further. 

The image you posted of the chart didn't include the whole thing (similiar to the spydercal) which was misleading at best. It look liked a printed chart. These tools seem to be the best solution. But I have found that when going shooting real life subjects, I still need to make adjustments, which kind of is crazy considering how much these tools cost. 

The Spydercal has a level on it so it's simple to keep that and the camera parallell.


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## neuroanatomist (Aug 31, 2011)

Viggo said:


> The image you posted of the chart didn't include the whole thing (similiar to the spydercal) which was misleading at best. It look liked a printed chart. These tools seem to be the best solution. But I have found that when going shooting real life subjects, I still need to make adjustments, which kind of is crazy considering how much these tools cost.
> 
> The Spydercal has a level on it so it's simple to keep that and the camera parallell.



Sorry about the misleading pic - I was looking for an image that showed the thin DoF you can easily measure with a tool like that.

I think that while they're expensive for what they are (production costs can't be very high), they're cheaper than almost any Canon lens and a LOT cheaper than even the cheapest L lens. Like a good RAW converter, they're something that can benefit nearly every shot you take with your camera(s) and most lenses. Worth it, IMO, especially considering the less than adequate results you can get with the free equivalents to those tools (I, too, have spent time with a cut-and-fold paper DoF chart!).

I didn't notice the SpyderCal has a level - that would do the trick, as do the sight gates on the LensAlign. Both the SpyderCal and the new LensAlign MkII also fold flat, unlike my Pro version that takes up more space when stored.


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## aldvan (Sep 3, 2011)

After reading and reading again all your posts, I spent a couple of days to setup a good microadjusting session. I opted for Jeffrey Friedl's method, that was well explained and didn't require to wait (and pay...) for a lensAlign to be shipped. The chart is well designed and the logic of the light grey indicators seems quite reasonable.
The lack of an instrumental system for a perfect alignment camera target required some additional time to spend leveling and measuring, but at last everything was perfectly aligned.
I started with the 1Ds3 and the 100-400, followed by the 5D2 and the same lens. At the beginning everything seemed working well, following well every step of the procedure. Frequently tested if the sensor was reading just the right target, turned off IS, fast shooting time, manually scanned from minimum distance to infinity before AF, camera on heavy tripod. Both cameras-lens seemed affected by a slight front-focusing corrected at -5 and -6.
Then, just for checking, I tried to set at -9 with the unlikely result to get again a front-focusing. Tried and tried again, getting similar results.
After reading an old article by Tom Jackson about the disalignment between the real sensor and the focus outlines in the viewfinder, I convinced my self that a lab procedure for microadjustment is risky and too exposed to minimal error factors.
So I reset everything and tomorrow I will go for what seems to me a more empirical and real world approach.
I will puth cameras and lenses on my tripod, aiming at the right distance for a wall plenty of contrasting and fine details. Then I will take 41 pictures focusing only with the central spot, adjusting from -20 to +20 and I will compare the results in LR3.4.
Quite rude but nor too time consuming, and it seems to me the exact procedure for what the MA system was designed...
Any opinion?


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## neuroanatomist (Sep 4, 2011)

Sorry, but to me it sounds like you tried the free method, and got what you paid for. Even the blog post you mention recommends LensAlign - there's a reason for that. For one thing, that one horizontal line is not optimal for some sensor point geometries (bear in mind the guy who developed that chart shoots Nikon, and they don't use the high-precision diagonal center AF point found in some higher-end Canon bodies). 

Also, you plan to shoot just one shot for each adjustment, and possibly that's what you did the first time. That's not a good plan - AF is accurate within a range, so you need several shots at each setting. Personally, I do 8 - two from infinity, then two without refocusing, then two from MFD, then two more without refocusing. Given the requirement of many shots per setting, comparing sharpness in that 'wall test' will be quite a challenge.


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## aldvan (Sep 4, 2011)

Neuroanatomist, I understand what you mean, but, at the same time, I'm beginning to understand also what Canon states in 1Ds owner manual: "Do this adjustment only if necessary. Note that doing this adjustment may prevent correct focusing from being achieved".
You told about taking 8 shots for each adjustment. That speaks to me about a random behavior statistically corrected, badly exposed to the risk of any random process... I don't know, now...
Since I haven't focusing problems, I'm seriously tempted to let everything as mother Canon did...


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## Viggo (Sep 4, 2011)

I have microadjusted every lens, and although, before I found out how, it caused me many sleepless nights. BUT to see every picture not as sharp as it was with liveview-af or MF, is even worse. It takes some trial and error and if a lens is too off (like mye 300 f2,8 was) you need to get it hardware calibrated with Canon first, otherwise it won't help if you're at +20 or -20 with Ma. 

What Canon do is solder one wire from one place to another in 4 steps. This is to move the POF a larger amount, and usually it helps a GREAT deal, but sometimes you find that your lens on your body is sharper in between those steps, and needing the MA to make it juuuust right. If you own a 2,8 lens or slower, it's less noticeable, but for me, who mostly use 1,2 and 1,4 lenses, this is the difference between no shot or the perfect shot.

Neuroanatomist: I agree with you on that note, compared to not getting what you paid for in a lens, that can easily be corrected, they are cheap. But considering it when you hold the cheap piece of plastic in your hand and think that you paid half a 17-40 for it is kinda strange. Luckily for me I can borrow one from work. And as soon as I get back, I'll take your advice and properly set it up, and adjust all my lenses one more, well, not the TS 17mm ;D


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## neuroanatomist (Sep 4, 2011)

aldvan said:


> You told about taking 8 shots for each adjustment. That speaks to me about a random behavior statistically corrected, badly exposed to the risk of any random process... I don't know, now...
> Since I haven't focusing problems, I'm seriously tempted to let everything as mother Canon did...



That is exactly the way it works - any mechaincal (or biological, or physical) process has some degree of randomness. AF is no different. Not every shot will be perfectly focused, period. Precision tells you how close one shot is likely to be to the next - with a high-precision center AF point and f/2.8 or faster lenses, shots fall in a range of 1/3 of the depth of focus at max aperture, with slower lenses, the precision is within one depth of focus at max aperture. Accuracy is different than precision. AFMA corrects for accuracy, but during the process of calibration, you still need to account for precision - thus, the multiple shots. Less-than-ideal accuracy is most evident with a thin DoF (fast lenses shot wide open with fairly close subjects). 

You may not know you have a problem unless you prolerly test for it...



aldvan said:


> Neuroanatomist, I understand what you mean, but, at the same time, I'm beginning to understand also what Canon states in 1Ds owner manual: "Do this adjustment only if necessary. Note that doing this adjustment may prevent correct focusing from being achieved".



Canon's advice is sound - I bet there are a lot of people out there who do the AFMA incorrectly, and end up in a worse place than no adjustment at all. Done properly, it's wonderful - pros used to send bodies + lenses to Canon for this sort of calibration (that was behind the genesis of Canon Professional Services, actually). Now, I can do it at home, my self, for less money and with faster turnaround. Almost all of my lenses have some amount of AFMA, and I can't imagine shooting with lenses like the 85mm f/1.2L II or 135mm f/2L without that feature.


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## aldvan (Sep 5, 2011)

Thank you, neuroanatomist. I'll bite the bullet and I'll order the LensAlign, although it is a steal!


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## aldvan (Sep 5, 2011)

Just one more question. To get rid of the pain of taking out the card and downloading the pictures, could it be a good idea to connect the camera by EOS utilities to a computer and check the focus directly on the monitor?


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## neuroanatomist (Sep 5, 2011)

Might work. I do find myself going back and forth to compare images, though. I'd suggest using tethered shooting to narrow the range, but still shooting (capturing) multiple shots 3-4 units on either side of what initially seems to be the correct setting.


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## PeterJ (Sep 28, 2011)

After reading this thread I ordered a LensAlign MkII which finally turned up today. They posted quickly but mail from the USA to Australia seems to have been a bit slow lately. Anyway I thought I'd post my results after using it on my lenses with a 7D:

24-70mm f/2.8L, +5
50mm f/1.4, -1
70-200mm f/2.8L IS II, +2
100mm f/2.8L IS Macro, +8

So my two most used lenses the 50 and 70-200 were pretty much on the money, I've always been happy with them but it'll be interesting to see if they are just that little bit now, that may have been a small "problem I didn't know I had". The 24-70 I've mainly used for things where I didn't want too shallow DOF so it doesn't really suprise me I'd never noticed that one.

The 100mm macro was my last purchase and I hadn't been happy with autofocus, but being my first macro lens just put it down to the usual recommendations of tripod + manual focus for macro. After trying a few things like AI servo in case it was me moving too much I'd pretty much given up on handheld for anything approaching macro. After the adjustment I just wandered around the house doing a few hand-held test shots and now everything is bang on target.

Anyway that's a lens I see I'll get much more use from now, so I'm glad to have heard about the LensAlign and about focus adjustment in general which I must admit I didn't know about until I read this thread .


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## Mt Spokane Photography (Sep 28, 2011)

aldvan said:


> After reading and reading again all your posts, I spent a couple of days to setup a good microadjusting session. I opted for Jeffrey Friedl's method, that was well explained and didn't require to wait (and pay...) for a lensAlign to be shipped. The chart is well designed and the logic of the light grey indicators seems quite reasonable.
> The lack of an instrumental system for a perfect alignment camera target required some additional time to spend leveling and measuring, but at last everything was perfectly aligned.
> I started with the 1Ds3 and the 100-400, followed by the 5D2 and the same lens. At the beginning everything seemed working well, following well every step of the procedure. Frequently tested if the sensor was reading just the right target, turned off IS, fast shooting time, manually scanned from minimum distance to infinity before AF, camera on heavy tripod. Both cameras-lens seemed affected by a slight front-focusing corrected at -5 and -6.
> Then, just for checking, I tried to set at -9 with the unlikely result to get again a front-focusing. Tried and tried again, getting similar results.
> ...



I use Jeffreys chart as a starting point, and then verify with real world photos at various distances at full aperture. Sometimes a little tweaking is needed, but its narrowed down any errors by quite a bit, usually to +/- 2.

I do plan to buy a lens alighn unit, but i never seem to get around to it, and all of my lenses produce very sharp images.


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## aldvan (Sep 28, 2011)

I received yesterday my LensAlign. Adding custom taxes and shipping the cost is unreasonable, per se, but the idea seems very good. I'm waiting for a relaxed moment of free time to MA my lenses...


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## aldvan (Sep 29, 2011)

Today I started the MAF campaign. I have some doubts and hope that neuroanatomist will solve them for me.
Aiming at the two holes for alignment, particularly with shorter than long tele lenses, as a 100 macro at the required distance of 25*focal lenght, it is impossible, due to parallax, to have both of the two holes perfectly centered. The rear ones are both perfectly visible trough the front ones, but slightly eccentrics. Is it ok anyway? I can't see any method to have both of them perfectly centered at short distance.
The 100 Macro IS seems ok with +4 and a real world test seems confirm that.
Second doubt. I found different answers in order to compensate MAF. To put it in a simpler way, if the perfectly focused point is behind the zero on the ruler (backfocus?) the adjustment should be + or -? I tried many times with controversial results... So, with LensAlign the 100-400 seems backfocusing, but with a backfocus adjustment of +14 (ok for the LA), the backfocusing gets worse in the real world...
Thanks in advance...


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## neuroanatomist (Sep 29, 2011)

aldvan said:


> Today I started the MAF campaign. I have some doubts and hope that neuroanatomist will solve them for me.



I'll do my best... 



aldvan said:


> Aiming at the two holes for alignment, particularly with shorter than long tele lenses, as a 100 macro at the required distance of 25*focal lenght, it is impossible, due to parallax, to have both of the two holes perfectly centered. The rear ones are both perfectly visible trough the front ones, but slightly eccentrics. Is it ok anyway? I can't see any method to have both of them perfectly centered at short distance.
> The 100 Macro IS seems ok with +4 and a real world test seems confirm that.



I had to do a little digging, and it turns out that the LensAlign website claim that, "_The graphics show the Pro model, however the MkII works exactly the same,_" is not quite true. I assume you have the MkII version, as that's what is currently shipping. I'd recommend aligning the hole on the left, i.e. the one in the center of the focus target, and let the other red circle be eccentric in the opening. 

The Pro model has 5 holes vs. two, one in the center and two on either side of that, and I usually try to ensure that the red bullseye in the middle is centered, and the ones to the side are displaced symmetrically (something you obviously cannot do with only one other hole).



aldvan said:


> Second doubt. I found different answers in order to compensate MAF. To put it in a simpler way, if the perfectly focused point is behind the zero on the ruler (backfocus?) the adjustment should be + or -? I tried many times with controversial results... So, with LensAlign the 100-400 seems backfocusing, but with a backfocus adjustment of +14 (ok for the LA), the backfocusing gets worse in the real world...



If your lens is backfocusing, i.e. the plane of sharp focus is behind the 0-point on the ruler, then you need to apply negative adjustment to correct it, i.e. -6 or -14, depending on how the severity of the backfocus. An AFMA of +14 would make backfocus substantially worse.


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## aldvan (Sep 29, 2011)

Thank you very much, neuroanatomist... After the first deluding attempts, I spent an hour to refine the procedure, and everything seems to go very well, now. Actually it needs a very longand accurate tune up, before starting, but after tha,t it is easier. The final result is 1Ds MkIII + 100-400 MAF +4, 5D MkII + 100-400 +2. Tomorrow I'll test this result in real world, and I'll tune up the other lenses...
During this kind of procedure you realize how flimsy are also good tripods. I have a Carbon Fiber and an heavy aluminum Manfrotto: I had to shoot with 10" timer to get a perfectly static image...


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## PeterJ (Sep 30, 2011)

aldvan said:


> Aiming at the two holes for alignment, particularly with shorter than long tele lenses, as a 100 macro at the required distance of 25*focal lenght, it is impossible, due to parallax, to have both of the two holes perfectly centered.


I noticed the same when doing my 100mm macro, on the back of the Lensalign Mk II the outer alignment hole is marked macro target so I used that one. I wasn't 100% sure though so tried the center one as well but results were too close to call, so it doesn't seem to make much difference. I'm guessing the outer one is just marked macro in case you're so close the center hole and ruler aren't visible at the same time.


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## aldvan (Sep 30, 2011)

PeterJ said:


> aldvan said:
> 
> 
> > Aiming at the two holes for alignment, particularly with shorter than long tele lenses, as a 100 macro at the required distance of 25*focal lenght, it is impossible, due to parallax, to have both of the two holes perfectly centered.
> ...


I suspected that but I wasn't sure what he intended with 'macro target'...


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## Viggo (Sep 30, 2011)

Neuroanatomist:

I took home with me a Spyder LensCal from work, and when using it, one actually doesn't need the distance I thought it would (comparing to the northernlight gif-image, pixel-allignment). And I adjusted 6 lenses on two bodies with half an hour, and they have all worked perfect since! Best tool you can buy ever.....

Thanks!


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## neuroanatomist (Sep 30, 2011)

Glad to help!


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## aldvan (Oct 1, 2011)

Final results: ISO 800, max opening, 10" timer, max focal lenght, central spot

1Ds MkIII
16-35 f/2.8 L II 0
24-105 f/4 L +8
100 f/2.8 L Macro I	+4
100-400 f/4-5.6 L	+4

5D MkII
16-35 f/2.8 L II +3
24-105 f/4 L +2
100 f/2.8 L Macro I +6
100-400 f/4-5.6 L +2

It's evident that both the systems, withe very lens, are front focusing, and in a different way. So, I guess, the constant result should be charged mainly to the body instead to the lenses.
It's interesting to note that measurement was a pleasure with the 1Ds, showing a repeatable, constant and very precise progression from backfocusing to front focusing. The 5D was more unpredictable, showing a slightly random series of results, not always well connected between adjustment and focusing...


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## Mt Spokane Photography (Oct 5, 2011)

Lens align has some very simple online instructions, and even a distance calculator that you can use to calculate the distance.

Just go to the web site and click on how to use it.

http://michaeltapesdesign.com/lensalign.html

For example, a 100mm f/2.8 can be aligned at and distance between 8.2 and 16.4 ft and get good results.


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## Mt Spokane Photography (Oct 10, 2011)

I finally bit the bullet and ordered a lens align MK II which I received a few days ago. I managed to find three hours to play with it, reading the instructions online first and using the calculator to determine the minimum distance. Then, I added about 10-20% so I was using it at about 30X the focal length, 25X for the long focal lengths.

I checked my setup by using the contrast detect focus in liveview. It should result in a high percentage of perfect focus achieved.

What I quickly found is that the process is sensitive to even tiny misalignments and particularly to any tilting of the camera from side to side. The front of the ruler almost always appeared to have more blur than the rear even when perfectly focused. I believe that this comes from being too near the 25X focal length, but did not have time to confirm it. I also found it necessary to turn off IS on my old 300mm f/4 lens to stop it from drifting. The others did not drift, not even the 100-400mmL.

Most of my lenses were perfect with zero autofocus adjustment, or just needed one or two points, but two,my 24-105mm L and 85mm L needed a -10 tweaking due to backfocusing, even though the target fell within the depth of field and appeared sharp. I did all the testing with my 5D MK II, using my 17mm prime, 24-105mmL, 35mm L, 50mm f/1.4, 85mm f/1.8, 100mm f/2.8L, 135mm f/2.8L, 70-200mm f/4 L IS, 100-400mm L, and 300mm f/4L.

I mounted the lens align on a old tripod I've had for 25 years which has a geared column that came in handy for raising and lowering the target to center it vertically. I had to slide and rotate the tripod horizontally to get horizontal alignment, and that was difficult. 

Some things I'd like to have to make it easier:

External lighting on the target, my lighting was bright, but not adequate to do the testing at ISO 200.

A macro type rail turned sideways would have been a excellent time saver. I have one out in my studio that I'll use next time.

A longer room. I used a hallway which allowed mt to view the target at sufficent distance for the telephotos, but my large tripod wanted more room for the legs.

I did not create any before and after photos, but I saved the final ones along with a standard focused with contrast detect (I tried manually, but could not do any better).

I'll want to take some real world images, but its cold and raining this week. We have had a cool and wet year so far in 2011.

Here is a example at 1:1 for my 35mmL and 100mmL comparing the image with contrast detect AF and the microadjusted phase detect.


100mmL with contrast detect AF






100mmL with phase detect AF (micro-adjusted)






35mmL with contrast detect AF






35mmLwith phase detect AF (micro-adjusted)


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