Lens Micro Adjustment

I have read many times on the forums of the necessity for micro adjustment of lens to camera body. In reality this seems a very essential exercise to carry out in order to achieve optimum focal fidelity, but one thing puzzles me; presumably the difference is measured in fractions of millimeters and would be obvious with a camera/lens mounted on a tripod, but I hand hold my Canon 100-400 and I would have thought that the body could move back or forward by some millimeters between achieving focus and the image being taken, resulting in a front or back focus effect. Could somebody with more technical knowledge than I have please explain?

What you have read is not true Dave and as you noted in your example it makes no sense at all. What is reprieved as the need for MA is usually poor technique, a.k.a "operator error", bad atmospheric conditions, slow shutter speed or a combination of all. I wrote an article on my blog that explains such common misunderstandings.

http://arihazeghiphotography.com/blo...always-needed/

In rare cases when you have a consistent focus shift MA may be needed, however it happens very infrequently.

For the record I have owned the following Canon gear since the time MA became a feature in 2008, EOS 40D, 50D, 7D, 1D MKIV, 1D-X, 5D Mark II and 5D Mark III with 400 f/5.6 (three copies), 300 f/2.8 MK I and II. 500 f/4 MK I, 600 f/4 MK II, 400 DO, 70-200 f/2.8 I and II. 70-300 L, 100-400 f/5.6 II, 24-70 f/2.8 II, 24-70 f/4 IS, 16-35 f/2.8 II and 24-105 L, extender 1.4X II and III, extender 2X III. I have also shot with 500 f/4 IS MK II, 200-400 f/4 IS and some other lenses. I have not micro-adjusted any of these/camera bodies and I think I care about sharpness more than most folks do.

I hope this helps.

Arash, thank you for the reply. It is nice to know that such a well respected expert confirms my thinking.
I write the following with all due respect to those who advocate the necessity to micro adjust and the sophisticated methods of carrying out the operation.
IMO it is something else to tinker with and if I were a tripod user I may well tinker; however, I hand hold my 7D and 100-400 Mk 2 for bird photography with all the variables this introduces and cannot see that trying to obtain the last fraction of a millimeter of focusing accuracy is of any value. However I was curious and carried out the following rough and ready method to test focusing accuracy. I downloaded and printed a lens calibration target and taped it to my kitchen window. I set the camera/lens on a sturdy tripod (I use it for landscapes) set to 400mm, and focused on the target at the maximum distance allowable by the size of my garden - about 25 feet. I took a single shot and examined it on the camera at full magnification and it looked to be sharply focused. I then selected AI Servo and HSC and shot ten frames, examination at full magnification confirmed that all were sharply focused with no variation between the frames.
I have come to the conclusion that successful hand held bird photography is 90% technique and 10% luck. I am still at the 10% luck stage but at least I have the comfort of knowing that my equipment is focusing correctly. Or do I?

I can speak from personal experience on this topic. A while back I tripped and fell breaking the lens mount on my Nikon D7000 camera. I sent the camera to Nikon Repair Services in New York state. Along with fixing the lens mount they cleaned the camera, sensor and re-aligned the mirror. After receiving the camera back from repair the camera/lens combination that had worked perfectly before was not consistently from focusing. In researching a solution to the problem I came across a method called Dot Tune (see the link to the article below). Using that method and dialing in a correction my camera is not consistently focusing correctly. I believe that the re-aligning of the mirror by the Nikon service tech changed the focus on the camera, Auto-Focus Fine Tune was able to correct it.

http://www.dpreview.com/forums/thread/3377109

Microadjustment has a definite place in a photographer's bag of tricks: it should be reserved for situations where there is a reproducible problem with either front or back focus. I do not recommend routine microadjustment as it typically creates more problems than it solves.

I agree with Doug on this. I've had numerous workshop clients where applied microadjustment was giving them unsharp images. Setting things back to zero cleared up the problem. Microadjusting as a matter of course is not necessary in my opinion. Thanks, Arash, for your nice article illuminating some of the reasons why.

Cheers,
Greg Basco

I believe there is a big difference in the need for routine micro-adjustment between Canon and Nikon. It seems that Nikon's need MA to a much greater degree than Canon according to someone who does MA as a business.

Quote:

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Originally Posted by DickLudwig

I believe there is a big difference in the need for routine micro-adjustment between Canon and Nikon. It seems that Nikon's need MA to a much greater degree than Canon according to someone who does MA as a business.

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I don't believe that is true, the basic concept and the points discussed above is the same between the two systems. I used Nikon between 2007-2010 before I completely switched to Canon, namely D300, D700, D3 and then D3s with 200-400 and 500VR and some other lenses. None of them needed any adjustment. I know a few prominent Nikon shooters, they also don't use MA AFAIK. Perhaps you are more likely to need it if you use third party lenses.

Quote:

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Originally Posted by arash_hazeghi

I don't believe that is true, the basic concept and the points discussed above is the same between the two systems. I used Nikon between 2007-2010 before I completely switched to Canon, namely D300, D700, D3 and then D3s with 200-400 and 500VR and some other lenses. None of them needed any adjustment. I know a few prominent Nikon shooters, they also don't use MA AFAIK. Perhaps you are more likely to need it if you use third party lenses.

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All I can say is that this is his actual experience doing many 100's of camera/lens MA's. He himself is a Nikon shooter who switched from Canon a # of years ago when Canon had focusing issues that they refused to admit/address. In his testing he has found that Canon's new series II lenses out perform or are at the very least equal to Nikon's newest lenses. He has tested both the Canon and Nikon lenses on a Sony a7R so that the senor is the same in both tests.

Hi Arash, the lens that I adjusted was a Nikon. The new 80-400mm F/4.5-5.6 VRII AF-S ED. It is possible that I may have damaged the lens when I fell but it seems to work fine with the adjustment. I am trying to get by till the summer heat before sending it in to be checked by Nikon Service Repair. Thanks for responding.

Quote:

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Originally Posted by DickLudwig

All I can say is that this is his actual experience doing many 100's of camera/lens MA's. He himself is a Nikon shooter who switched from Canon a # of years ago when Canon had focusing issues that they refused to admit/address. In his testing he has found that Canon's new series II lenses out perform or are at the very least equal to Nikon's newest lenses. He has tested both the Canon and Nikon lenses on a Sony a7R so that the senor is the same in both tests.

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I personally don't trust the credibility of this source, especially when financial incentives are involved to get more clients. The Canon super telephoto lenses are superior to that of Nikon in every aspect but Nikon is no slouch either, as evident by many excellent photographs posted on this forum with Nikon gear (e.g. Alan Murphy) . their lenses are just a bit too heavy for folks who want to hand hold, the AF is bit slower and they don't perform as well when coupled with an extender. But that doesn't mean they need micro-adjustment.

best

Quote:

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Originally Posted by Joseph Przybyla

Hi Arash, the lens that I adjusted was a Nikon. The new 80-400mm F/4.5-5.6 VRII AF-S ED. It is possible that I may have damaged the lens when I fell but it seems to work fine with the adjustment. I am trying to get by till the summer heat before sending it in to be checked by Nikon Service Repair. Thanks for responding.

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it is possible that when you dropped the lens one of the elements got slightly miss-aligned and hence the focus shift. But if you are happy with the results why bother sending it back ? just enjoy it. :S3:

Hi all,
Just thought I'd throw my $.02 in. Although I have not had as many Lens and camera combinations as Arash and Doug, I have had enough of them to know that Micro adjusting is not something to worry about unless you have a ongoing focusing problem.
There have been many discussions throughout this and other forums about this subject. I for one am in the same boat as most of you, being that I am very critical of Sharp focus and I have never micro adjusted a camera or lens combination, ever.
As discussed in Arash's informative article, Most soft images come from a combination of either user Error or environmental conditions. Once all of these conditions are well understood, you will have a better understanding of why some frames are soft and others are sharp and you'll stop blaming your gear. Early on I was sure that I had problems with my 500 mm and was testing and looking into Micro adjusting it but then the next day it was shooting sharp again. It had me really scratching my head until I started understanding what was going on. Heat refraction and shimmer we're to blame for most of my soft images and once I understood this, I wasn't worried about my gears consistency. Also as Arash mentioned in his article, good hand holding technique and faster shutter speeds Will help to clear up your soft images also. I just had a friend with a similar dilemma and was micro adjusting his combo until he didn't know which way was up. Finally he sent it into Canon and they reset everything back to zero and and send it back to him informing him that they have tested it and it was working perfectly. After discussing things with him I realized that his problem was heat refraction also as he was shooting into the late morning hours and the rising heat was causing inconsistency in his frames.

To caption, if it aint broken, don't fix it.

David