Canon Lens Calibration...

[rpcrowe]

This question about Canon DSLR cameras and various lenses has five parameters. I don't have a specific lens in mind, I have not needed to calibrate any of my lenses in the past. This is just for my general knowledge...

1. If I have a third party lens (such as a Tamron or Tokina) that I use with my Canon DSLR cameras and it front or back focuses; can I use the Canon calibration to fix this?

2. If I use the same lens with more than one camera body, do I need to calibrate the lens for each body and will the setup remember which lens/body combination I am using?

3. Is lens calibration a one-time thing or do I need to check the lens regularly?

4. Will older lenses such as the EF 50mm f/1.8 Mk.1 or the EF 135mm f/2.8 SF calibrate if needed?

5. I understand the principle behind calibrating a prime lens but, is calibration of a zoom lens possible?

[DanK]

I have only once calibrated, but here's what I think are the answers:

1. If I have a third party lens (such as a Tamron or Tokina) that I use with my Canon DSLR cameras and it front or back focuses; can I use the Canon calibration to fix this?

I don't know what you mean by Canon calibration, but if you mean calibration set in the camera body, then yes. I was able to do this with a Tamron lens in the past, if I remember right.

2. If I use the same lens with more than one camera body, do I need to calibrate the lens for each body and will the setup remember which lens/body combination I am using?

The calibration is specific to the combination of a lens and a body, so it's best to calibrate each body separately, although I suspect that most of the variation is lens, not body, so I would expect the corrections to be similar. The correction is in the camera's memory, of course, so you would need to dial it in for that lens on the second body even if you just copied it.

3, 4: I don't know.

5. I understand the principle behind calibrating a prime lens but, is calibration of a zoom lens possible?

Yes, but any error is likely to be inconsistent across the focal length range. That was the case for the one zoom I calibrated on my 50D, so I calibrated it for the longest focal length, figuring that would be where it matters most. I believe that some of the new Canon bodies will allow you to enter two corrections for a zoom, for shortest and longest length, but I haven't yet played with this.

[rpcrowe]

Thank you Dan...

I also found this information. I was calling it "calibration" when the correct Canon terminology is micro adjustment...

https://www.learn.usa.canon.com/app/...de_desktop.pdf

[pschlute]

You have had most questions answered so

3. It should be a one-time-thing. Of course your lens or camera could go off over time.

5. You need to test at various lengths in the zoom range.. Make an adjustment for either: where the AF misses most or where you use the lens most.

The most important thing is to use a tripod; use light that corresponds to what you shoot under normally; do not rely on one-take. Do a "best out of 10 tests"

[DanK]

Do a "best out of 10 tests"

Very good advice. There is software that will do this for you, focusing again and again and calculating what I think may be a moving average. It's called Reikan FoCal, if I recall. I bought and used it years ago. Quite easy to use, if I remember, and I found that the combination of camera and lens I tried it on was somewhat erratic. I haven't tried it with my newer bodies, and I don't know whether I am entitled to upgrade for free to the current version.

[Shadowman]

I'm not a Canon shooter but I would think that unless the micro adjustment software was designed for a specific lens/camera combo then any adjustments would only be trial and error/subjective. My counter argument is only to further the conversation because my comments are based on the assumption of a camera sensor/lens configuration adjustment. Wouldn't any Canon micro adjustment be based on the lens design, a Tamron/Sigma/Rokinon lens design would not match a Canon lens so any micro adjustment would certainly be off by a few degrees and any adjustment regardless of the lens would also entail some physical/user interaction so one shooters adjustment might not agree with another's using the same gear.

[DanK]

I'm not a Canon shooter but I would think that unless the micro adjustment software was designed for a specific lens/camera combo then any adjustments would only be trial and error/subjective. My counter argument is only to further the conversation because my comments are based on the assumption of a camera sensor/lens configuration adjustment. Wouldn't any Canon micro adjustment be based on the lens design, a Tamron/Sigma/Rokinon lens design would not match a Canon lens so any micro adjustment would certainly be off by a few degrees and any adjustment regardless of the lens would also entail some physical/user interaction so one shooters adjustment might not agree with another's using the same gear.

That's not how microadjustment works. It's an empirical adjustment, not anything based on design characteristics. It works by checking the discrepancy between AF using phase detection and manual focus or AF using contrast detection. The only data Canon needs is the ability to identify the lens so that the MFA adjustment can be linked in its memory to that particular lens.

[Shadowman]

That's not how microadjustment works. It's an empirical adjustment, not anything based on design characteristics. It works by checking the discrepancy between AF using phase detection and manual focus or AF using contrast detection. The only data Canon needs is the ability to identify the lens so that the MFA adjustment can be linked in its memory to that particular lens.

Hi Dan,

But will Canon cameras recognize third party lenses?

[zen]

Hi Dan,

But will Canon cameras recognize third party lenses?

That, of course, is the key question. The answer is. . . it depends. Those lenses that are designed to be used on Canon bodies, and some are, will work fine. Although I do not own a non-Canon lens, one I tested on my 5d3 in a local shop a few years ago, did afma. I didn't buy it so don't know how long the body would hold the setting. This is one of those questions that can only be answered by trying it.

Zen

[NorthernFocus]

Delving off into "calibrating" lens/camera with software designed for that purpose is a good demonstration of the old wisdom that ignorance is bliss. The process reveals how much variability there is in these devices that most of us believe to be precision equipment. After going through a couple of calibration sessions one may re-define "precision". For a good portion of my career I was involved in instrument/analyzer calibration, machining tolerances, etc. In essence, defining the precision needed out of various devices to accomplish an intended purpose. With that background and having conducted several calibration/micro-adjustments on camera gear, and having had extensive discussions with Nikon service personnel regarding results, I've come full circle. Now if I have reason to suspect an issue with a given lens/camera combo, I take a few handheld test shots of a brick wall/picket fence/field of grass, and if the focal plane appears to be reasonably close to the center of DOF I call it good and go shoot something more interesting than brick wall/picket fence/field of grass.

Having said all of that, I fully realize the human need to prove to one's self that wheels do in-fact roll

[pschlute]

The question of whether to calibrate or not can depend on how you shoot your pictures and what you do with them.

If you don't pixel-peep, and view "fit to screen", or online you will probably not notice a camera is mis-focusing especially if you don't often shoot wide open with a fast lens.

If you want to make a large print, say 24"x16" of an image captured at f1.4 you will absolutely notice if your camera has not nailed the focus spot on.

My camera, (not a Canon) requires the maximum + adjustment to correct back-focus with a number of my lenses. I for one am very glad DSLR manufacturers make these adjustments possible.

[russellsnr]

Have Canon, Sigma and a Tamron lens and bought Focal software to calibrate them all to both my 6D and 70D takes a while to do them all but on a rainy day, stuck indoors Printed off the target rather than bought there's and they do recomend re-calibration on a regular basis (6 to 12 months) https://support.fo-cal.co.uk/?_ga=2....869.1533366175
Russ.

[Shadowman]

Have Canon, Sigma and a Tamron lens and bought Focal software to calibrate them all to both my 6D and 70D takes a while to do them all but on a rainy day, stuck indoors Printed off the target rather than bought there's and they do recomend re-calibration on a regular basis (6 to 12 months) https://support.fo-cal.co.uk/?_ga=2....869.1533366175
Russ.

I read in the link that FoCal's method of operation and they state they use software supplied by Nikon/Canon to make adjustments to third party lenses.

[DanK]

FoCal and most other MFA adjustment methods do not adjust lenses. The adjust bodies to offset their errors with specific copies of specific lenses. The one exception of which I am aware is the Sigma dock system, which I haven’t used and don’t understand. Others may have come up with other systems of which I am unaware.




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