Performing autofocus micro-adjustments on EOS 80D and 18-135mm Nano USM lens

[vze3ryci]

What is the BEST way to perform an autofocus micro adjustment on my EOS 80D and 18-135mm nano USM lens? Should I do it myself using "FOCAL" or send them to Canon?

[shadowsports]

Greetings,

Have you confirmed the camera/lens combo is front or back focusing?  What leads you to believe this?  

How long have you owned this gear.  Is this new behavior?  Does the behavior occur with more than one lens?  Please provide some history and what has led you to believe the camera or lens is in need of adjustment or calibration.  Could it be related to technique?

[vze3ryci]

Okay. No, I don't know if it's front/back focusing. What I do know is that over time, focus has lost sharpness [I've owned the camera and lens combo for over 7 years]. Yes, it occurs with my Canon 50mm 1.8 STM as well as my Canon 55-250mm STM. Now, I've just recently started considering working with the micro-adjustments, however, I want to make sure it's done in the best way. My local camera shop provides the service, but only within the camera body [not lenses]. That's why I'm seeking the best advice possible. Thank you, very much!

[Waddizzle]

I agree with Rick’s point.  You should only attempt to perform an AFMA it you conclusive evidence that the lens is front or back focusing.  Just because you may have several photos that seem soft isn’t conclusive.   

Performing AFMA is just as much a test of the skill of the photographer as it is the gear.

Try this using a tripod or some other form of hands free camera support.  Take a photo of something that is 2-4 feet tall sitting in a grassy area.  Place the object at a distance of 50x the focal length.  Adjust the camera position so that it is pointing towards the target without being angled up or down.

You want to refocus before you take a test photo and then switch the lens MF.  You also want to take test photos at maximum aperture.

Take a couple of photos using the shutter button and the 2/10 shutter delay timer.  Take a few more using Mirror Lockup, and a few more in Live View mode.  Move the setup and repeat the test shots. 

Review the photos.  Is the test object in focus in every shot?  Take a look at the grass!  Is the grass near the test object in focus?  

Is the grass in front or behind the test object in sharp focus?  It shouldn’t be.

[vze3ryci]

Much was said, however I will reiterate... my photos "plural", of late, are soft [not just a couple]. I've been using this camera for upwards of 7 years. I think I know the difference. I may not be a professional, I certainly am not, but I've also been at this for a bit of time, long enough to know that a problem has developed (one not attributable to 'user error.') Again, my question was  a simple one, or so I thought.

What is the BEST way to perform an autofocus micro adjustment on my EOS 80D and 18-135mm nano USM lens? Should I do it myself using "FOCAL" or send them to Canon? I've already concluded that it needs to be done. Now, I'm just looking for sound advice as to the best way to go about it... with all due respect. 

[deebatman316 · Accepted solution]

AFMA Adjustment doesn’t change how sharp a lens is. That is a very common misconception about it. The only thing it does is correct for front or back focusing during viewfinder shooting. In live view it’s also not needed. This is due to the image sensor handling AF. So front or back focusing can’t happen. Can you post some pictures of the issue. An AFMA Adjustment will NOT fix the problem that you’re describing. Also it’s not common for a Nano USM lens to need an AFMA Adjustment. Those lenses use a very fast and accurate AF motor. Usually it’s the older slower AF motors such as Micro Motor and Arc Form Drive. That needs an AFMA Adjustment done.

[Waddizzle · Accepted solution]

“ What is the BEST way to perform an autofocus micro adjustment on my EOS 80D and 18-135mm nano USM lens? Should I do it myself using "FOCAL" or send them to Canon? I've already concluded that it needs to be done. Now, I'm just looking for sound advice as to the best way to go about it... with all due respect. “

FOCAL does an excellent job, I am told.  I am not certain Canon still services the 80D, anyway. I use instructions from a YouTube video named “Dot Tune.”  Be warned, it’s easier to get it wrong than it is to get it right.  

The method in the video is pretty simple and straightforward.  But it skips over a few nuances that can make it big difference.

Light.  If you will be using the lens outdoors, then don’t calibrate it indoors under artificial lighting.

Sampling.  This is the most common trip point in the process. The video tells you to take one test shot and then adjust.  You should take multiple samples and average the results. 

Your results will vary, but you should see a clear trend.  I usually an average at least 8 samples.  Discard the “Hi and Lo” results.

If your results are all over the place, then you need to be more mindful of what you’re doing.  Some consumer lenses will be all over the place no matter how careful you are.  

The actual adjustment “moves” the Focus Plane closer or farther away.  A negative value “reduces” the distance, which is appropriate for back focusing.  A positive value “increases” the distance, which is appropriate for front focusing.  Perform the test I described earlier to determine whether you even need a focus adjustment.  

Don’t assume that you got it right the first time.  Almost no one does.  Give it a week and retest.  You might have different results!  

[jrhoffman75]

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@vze3ryci wrote:

Okay. No, I don't know if it's front/back focusing. What I do know is that over time, focus has lost sharpness [I've owned the camera and lens combo for over 7 years]. Yes, it occurs with my Canon 50mm 1.8 STM as well as my Canon 55-250mm STM. Now, I've just recently started considering working with the micro-adjustments, however, I want to make sure it's done in the best way. My local camera shop provides the service, but only within the camera body [not lenses]. That's why I'm seeking the best advice possible. Thank you, very much!

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Focal works well and you get instant feedback because it shows the before and after. 

Did you try this quick test? 1. Focus using LiveView. Is the image sharp? 2. Switch camera to viewfinder focus (turn off LiveView). 3. Focus using shutter button. 4. Does the lens focus ring rotate? If so there is a focus mismatch. 

[vze3ryci]

Thank you, Demetrius. Much appreciated! Can you please answer one question for me... you mentioned something that I found very interesting, but don't really understand. I believe you said that if I'm focusing using "live view," AFMA isn't necessary (or won't be effective or even matter). Please explain what you mean by that as it sounds very interesting and since I shoot exclusively using "live view" (I actually can't remember the last time I even used the viewfinder),  I think you might have some very valuable/helpful information for me. And PLEASE be detailed in your explanation as I sometimes have a little difficulty grasping technical issues. Sir, I really do appreciate your help!

[deebatman316 · Accepted solution]

AFMA Adjustment corrects for front or back focusing in an SLR or DSLR camera. The AF sensors in an SLR are under the mirror. While the image sensor is before the AF sensors. Which can cause font or back focusing problems. In a Mirrorless or a DSLR camera in live view. The image from the lens is projected directly on the image sensor. Therefore AFMA adjustment is NOT needed at all. Front or back focusing is NOT possible. The plane of focus is directly on the image sensor. Unlike a DSLR where it’s on the AF sensor. But the image sensor is further back. Which can cause front or back focus because focus is not on the same plane.