The AFMA myth.

Started 7 months ago | Discussions
Dave
Dave Veteran Member • Posts: 5,049
Re: The AFMA myth.
2

rmexpress22 wrote:

Dave wrote:

rmexpress22 wrote:

AFMA exists. AFMA is often needed. It's not a myth.

My 35mm 1.4 Art needed substantial AFMA with the Sigma dock. My 85mn 1.4 Art needed none for the first two years. Then I did a shoot where it front focused and dialed +1 and all was good in the world.

Most threads start out by users stating that they are not able to focus reliably consistently. No need for a million questions to diagnose.

Is that a Canon lens?

Does it matter? The discussion is whether it's needed. Not whether Canon lenses need it. But to narrow things down, my 80D needed AFMA with a Canon 10-18mm, a 50mm 1.4, but not a 85mm 1.8. All Canon, all different AFMA needs.

Did you see "For most users, especially if they are using Canon glass on their Canon bodies, AFMA is not required." in this thread's original post? You apparently are not most users. And your first post was about a Sigma lens.

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BirdShooter7 Veteran Member • Posts: 4,271
Re: The AFMA myth.

To each his own, if what you are doing works for you then more power to you. I know that I check calibration on all of my lenses and many of them benefit from it. I do wonder how you know that most donโ€™t need AFMA. Is there some data available that demonstrates that fact?

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BirdShooter7 Veteran Member • Posts: 4,271
Re: The AFMA myth.

It is definitely a great diagnostic tool and can quickly determine if calibration is needed or not so you can narrow down the potential cause of soft photos. In my opinion it is one of the first things to try. Once you know everything is properly calibrated you can focus on technique or other causes.

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BirdShooter7 Veteran Member • Posts: 4,271
Re: The AFMA myth.
1

So checking calibration is one of the last things to try? Interesting...

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DavidArmenPhoto Regular Member • Posts: 354
Re: The AFMA myth.

Andy01 wrote:

I think that AFMA is useful in general, and can be EXTREMELY useful in some cases. I have tested every lens I have owned with 70D and 6D ii (the only two bodies I have owned with AFMA), and every one of them needed some degree of adjustment, often not major though. Lenses include Canon 24-105L, 24-105L ii, 100-400L, 100-400L ii & EF 35 f2 IS, and a Sigma 17-50 f2.8 (which I would rather not even talk about).

I do agree though that there are people here who blame every missed focus on AFMA (or lack of), and there are people here who seem to be much better than me in spotting front or back focusing (a recent example of an orca's fin that was not focused correctly - people spotted front focus on relatively calm reflective water, and suggested AFMA - better than me - AFMA may have been required or have helped, but it was pretty hard to tell from the image in question).

And a mention above of a couple of mm - a couple of mm can make all the difference when trying to shoot a bee in a flower at 400mm

Colin

What’s wrong with your copy of the Sigma 17-50? It’s a pretty sharp lens for its price actually.

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MyReality
MyReality Contributing Member • Posts: 907
Re: The AFMA myth.

"Myth" Definitions:

1. : a popular belief or tradition that has grown up around something or someone.

2.  An unfounded or false notion.

Calling it a "myth" may be a little harsh.  I do not put it in the same class as "3D Pop" or "micro-contrast", since it is a hardware adjustment and measurable.

Your point of whether it actually makes any noticeable difference is more important.  The visual quality of photos taken before AFMA speak for themselves and make AFMA irrelevant except as an exercise for pixel peepers.

Do you have to have a steak knife when you cut steak or will any sharp knife do just fine?

I do not look at the edges of the piece of meat before I put it in my mouth.  It tastes great no matter what knife I used.

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jrkliny
jrkliny Veteran Member • Posts: 4,119
Re: The AFMA Bells and Whistles

Myth is probably a misleading word.  AFMA exists on some cameras and is no myth.  How about Bells and Whistles instead?  The implies a feature that is supposed to be attractive but is also superfluous.

Up until the 90D I have always had Rebel models without AFMA.  I was always concerned that I was going to have AF issues without the microadjust feature.  I did lots of testing for every new camera body and/or lens.  With all the testing in the past, I never saw any need for AFMA.

When I got the 90D I spent more time looking for front or back focusing issues.  I looked at 4 lenses: 18-135, 15-85, 60 macro and the 55-250.  I set up a close target and then moved to a longer distance for each lens.  I used a tripod, cable release, mirror lockup, and turned off lens stabilization.  Of course I also shot in good diffuse light with the lenses wide open.  My target was a sheet from a magazine and I also propped up a ruler at a 45 degree angle.  I compared results for AF and liveview at 10x.  I also check the ruler for any indications of front or back focusing.  I did at least 3 tests for each lens at the 2 distances.  AF seemed dead on and very consistent for every test.

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gipper51 Veteran Member • Posts: 5,064
Re: The AFMA myth.
1

Interesting to see the range of opinions on this topic here. For me personally, checking a new body or lens for MFA is one of the first things I do whenever I acquire them. I've found over the years that more of my lenses need MFA on my bodies than not. Every body I've owned has had multiple lenses that produced better results overall thanks to MFA.

Many lenses just need small adjustments, some have needed huge changes (like -15). My old Canon 80-200 f2.8L was practically unusable at less than f8 because it backfocused so bady (on every camera). But thanks to MFA, it could be calibrated to perfection wide open.

Testing if a lens needs MFA is not hard to do, and doing the actual calibration is quite simple.  I can take a lens out and with a series of pics determine if it needs MFA in about 15 minutes.  I won't buy a DSLR any more that lacks MFA adjustments. For what camera gear costs I'm expecting excellent results consistently wide open...I'm paying for and expecting pixel-peeping level sharpness.  In multiple instances after doing MFA a lens has gone from "I'm not impressed" to "wow!" when shot wide open.  If the camera gives me a tuning tool that allows for better results than I can get out of the box, damn straight I'm going to utilize it. YMMV.

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jrkliny
jrkliny Veteran Member • Posts: 4,119
Re: The AFMA myth.

gipper51 wrote:

Interesting to see the range of opinions on this topic here. For me personally, checking a new body or lens for MFA is one of the first things I do whenever I acquire them. I've found over the years that more of my lenses need MFA on my bodies than not. Every body I've owned has had multiple lenses that produced better results overall thanks to MFA.

Many lenses just need small adjustments, some have needed huge changes (like -15). My old Canon 80-200 f2.8L was practically unusable at less than f8 because it backfocused so bady (on every camera). But thanks to MFA, it could be calibrated to perfection wide open.

Testing if a lens needs MFA is not hard to do, and doing the actual calibration is quite simple. I can take a lens out and with a series of pics determine if it needs MFA in about 15 minutes. I won't buy a DSLR any more that lacks MFA adjustments. For what camera gear costs I'm expecting excellent results consistently wide open...I'm paying for and expecting pixel-peeping level sharpness. In multiple instances after doing MFA a lens has gone from "I'm not impressed" to "wow!" when shot wide open. If the camera gives me a tuning tool that allows for better results than I can get out of the box, damn straight I'm going to utilize it. YMMV.

Statements like this are absolutely baffling to me. As you point testing is relatively easy.  With careful testing it should be possible to see very minor focusing issues.  So why are some of us not able to see any need for adjustments and others need to adjust every lens and camera body combination?  I certainly cannot argue against your experience but I also know my own results and the consistency I saw.

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gscotten
gscotten Senior Member • Posts: 1,770
Re: The AFMA Bells and Whistles

jrkliny wrote:

I looked at 4 lenses: 18-135, 15-85, 60 macro and the 55-250.

I went through a similar process and none of my lenses needed AFMA, either. Like you, all of my lenses but one are slow enough to have a relatively deep DOF anyway. My 50mm f/1.8 was spot on. So I leave my AFMA turned off.

I suspect if one uses a lot of fast primes, particularly off-brand or inexpensive lenses, that a larger percentage would find AFMA useful. I do not think it is a gimmick or useless. I am happy to have it, even if I don't need it...yet.

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George

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jrkliny
jrkliny Veteran Member • Posts: 4,119
Re: The AFMA Bells and Whistles

gscotten wrote:

jrkliny wrote:

I looked at 4 lenses: 18-135, 15-85, 60 macro and the 55-250.

I went through a similar process and none of my lenses needed AFMA, either. Like you, all of my lenses but one are slow enough to have a relatively deep DOF anyway. My 50mm f/1.8 was spot on. So I leave my AFMA turned off.

I suspect if one uses a lot of fast primes, particularly off-brand or inexpensive lenses, that a larger percentage would find AFMA useful. I do not think it is a gimmick or useless. I am happy to have it, even if I don't need it...yet.

So this makes some sense. I don't own any 3rd party lenses, but perhaps they would not be optimized to work with the Canon camera bodies.

Maybe this also becomes more important for fast lenses. The fastest lens I have is an old 35/f2. Perhaps I should check it.

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AshleyMC Regular Member • Posts: 483
Re: The AFMA myth.

The term “myth” should be replaced by “misconception” or “misuse”.

AFMA is required in certain cases of body-lens combination — rare, but needed.

For example, we have two 6D Mark II bodies between my partner and myself. His needed 3 AFMA operations and mine needed only 1.

Like every technical feature, it must be used with understanding and deliberation.

No technical features, no matter how simple or sophisticated, will fix operator’s errors. If people use AFMA in a random fashion, without proper analyses, nothing will be solved.

gipper51 Veteran Member • Posts: 5,064
Re: The AFMA myth.

jrkliny wrote:

gipper51 wrote:

Interesting to see the range of opinions on this topic here. For me personally, checking a new body or lens for MFA is one of the first things I do whenever I acquire them. I've found over the years that more of my lenses need MFA on my bodies than not. Every body I've owned has had multiple lenses that produced better results overall thanks to MFA.

Many lenses just need small adjustments, some have needed huge changes (like -15). My old Canon 80-200 f2.8L was practically unusable at less than f8 because it backfocused so bady (on every camera). But thanks to MFA, it could be calibrated to perfection wide open.

Testing if a lens needs MFA is not hard to do, and doing the actual calibration is quite simple. I can take a lens out and with a series of pics determine if it needs MFA in about 15 minutes. I won't buy a DSLR any more that lacks MFA adjustments. For what camera gear costs I'm expecting excellent results consistently wide open...I'm paying for and expecting pixel-peeping level sharpness. In multiple instances after doing MFA a lens has gone from "I'm not impressed" to "wow!" when shot wide open. If the camera gives me a tuning tool that allows for better results than I can get out of the box, damn straight I'm going to utilize it. YMMV.

Statements like this are absolutely baffling to me. As you point testing is relatively easy. With careful testing it should be possible to see very minor focusing issues. So why are some of us not able to see any need for adjustments and others need to adjust every lens and camera body combination? I certainly cannot argue against your experience but I also know my own results and the consistency I saw.

I'm sure much of it comes down to what lenses are used, and luck of the draw with a particular body/lens combo. Several of my lenses are older models or 3rd party glass and they have required the highest levels of MFA across numerous bodies. My newer Canon lenses like 16-35 f/4L and 18-135 STM have been pretty spot-on. So if all of your glass is fairly recent, it may be less of an issue. But if your'e shooting with glass from the 90s or even earlier, it could be more prone to focus problems.

Ironically, my 70-200 f2.8L required zero MFA on my 5D4, yet on my 7D2 it required different values for wide and telephoto settings for best results. Only -3 and -1 respectively, but there was noticeable improvement from 0, especially in focus consistency. Many shots would be perfect, but I'd get a few that for no good reason seemed to have very slight back focus where I wouldn't expect it (like a static portrait). MFA solved the inconsistency.

I've had body/lens combos that seems great with default settings in a quick test, but after weeks or months I'd notice that when it does miss focus unexpectedly, I'll take a mental note if it's front or back focused. If it seems that the focus is always off in one direction when it does miss, I'd give it a 1 or 2 MFA bump. That small bump usually reduced the number of random AF misses.

My 5D4 currently only has two lenses MFA'd out of 5 that I typically do this with, which is the best body I've had yet in regards to needing MFA. And both lenses are only at a +2. So if this were my only body I could make the case that MFA is not really needed. But in the half dozen other bodies I've owned with MFA capability, the 5D4 is the exception to this.

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OP Distinctly Average Contributing Member • Posts: 649
Re: The AFMA myth.

AshleyMC wrote:

The term “myth” should be replaced by “misconception” or “misuse”.

AFMA is required in certain cases of body-lens combination — rare, but needed.

For example, we have two 6D Mark II bodies between my partner and myself. His needed 3 AFMA operations and mine needed only 1.

Like every technical feature, it must be used with understanding and deliberation.

No technical features, no matter how simple or sophisticated, will fix operator’s errors. If people use AFMA in a random fashion, without proper analyses, nothing will be solved.

At least you read the body rather than just jump on the title as some have here.

AMFA is great, but only once you have looked and investigated all the real reasons an image is soft. That is my beef here, not the tool but the repeated advice given without consideration. Looks to me you understand that fully. You would be amazed at just how many times I have been sat in a hide or similar with someone who is struggling with their camera. It happened today in fact. The owner was getting really frustrated. He said he had tried all the things suggested and had spent ages tuning his lens. I took a look for him and it was plainly obvious that shooting kingfishers with a 500mm lens at 1/30th was his problem. I reset his afma to zero, upped his shutter speed and ISO. He left grinning as he had two weeks since he bought the lens and camera been worried it was faulty. He took bad advice based on a couple of shots he posted on a forum. He didn't fully understand AFMA or how to use it. He had dropped his shutter speed as his first shot with that combo was run down for being noisy and he was advised to keep his ISO below 400 with "that body" which happened to be a Nikon known for working well at high ISO. So bad advice added to bad advice left him upset at his 10k investment. What a lot of people on these forums forget is that not all users are technically minded. Especially in the world of birding there are a lot of older people who turn 55 or whatever and spend a wedge of their pension fund on a new hobby. They need  considered advice, not being thrown to the leopards.

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Leigh A. Wax Senior Member • Posts: 1,138
AFMA is simply a tool.
1

AFMA is simply a tool to provide adjustments that can be used for AF Trouble-shooting, as well as correction, albeit it's success dependent upon the methods applied.

There's a "gazillion" tools on modern Digital cameras, from the "oldies" like Back-button-AF, AE-Lock, AV-TV-P-M, plus myriad Custom Function's.

While I favor the tools, & methods that work for me, I don't consider those favoring other methods, are somehow "flawed".:-|

OP Distinctly Average Contributing Member • Posts: 649
Re: AFMA is simply a tool.
1

Leigh A. Wax wrote:

AFMA is simply a tool to provide adjustments that can be used for AF Trouble-shooting, as well as correction, albeit it's success dependent upon the methods applied.

There's a "gazillion" tools on modern Digital cameras, from the "oldies" like Back-button-AF, AE-Lock, AV-TV-P-M, plus myriad Custom Function's.

While I favor the tools, & methods that work for me, I don't consider those favoring other methods, are somehow "flawed".:-|

As with any tool, you have to understand how to use it, why and when. Many do not.

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ThrillaMozilla Veteran Member • Posts: 4,412
Re: The AFMA myth.
3

I'm going to take some excerpts and reformat them a little for emphasis.

Distinctly Average wrote:

AMFA is great, but only once you have looked and investigated all the real reasons an image is soft.

...The owner was getting really frustrated. He said he had tried all the things suggested and had spent ages tuning his lens. I took a look for him and it was plainly obvious that shooting kingfishers with a 500mm lens at 1/30th was his problem. I reset his afma to zero, upped his shutter speed and ISO. He left grinning as he had two weeks since he bought the lens and camera been worried it was faulty. He took bad advice based on a couple of shots he posted on a forum.

...he was advised to keep his ISO below 400 with "that body" which happened to be a Nikon known for working well at high ISO. So bad advice added to bad advice left him upset at his 10k investment.

What a lot of people on these forums forget is that not all users are technically minded. ...They need considered advice, not being thrown to the leopards.

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BirdShooter7 Veteran Member • Posts: 4,271
Re: The AFMA myth.

Definitely AFMA is rocket ๐Ÿš€ science!

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Andy01 Senior Member • Posts: 3,094
Re: The AFMA myth.

DavidArmenPhoto wrote:

Andy01 wrote:

I think that AFMA is useful in general, and can be EXTREMELY useful in some cases. I have tested every lens I have owned with 70D and 6D ii (the only two bodies I have owned with AFMA), and every one of them needed some degree of adjustment, often not major though. Lenses include Canon 24-105L, 24-105L ii, 100-400L, 100-400L ii & EF 35 f2 IS, and a Sigma 17-50 f2.8 (which I would rather not even talk about).

I do agree though that there are people here who blame every missed focus on AFMA (or lack of), and there are people here who seem to be much better than me in spotting front or back focusing (a recent example of an orca's fin that was not focused correctly - people spotted front focus on relatively calm reflective water, and suggested AFMA - better than me - AFMA may have been required or have helped, but it was pretty hard to tell from the image in question).

And a mention above of a couple of mm - a couple of mm can make all the difference when trying to shoot a bee in a flower at 400mm

Colin

What’s wrong with your copy of the Sigma 17-50? It’s a pretty sharp lens for its price actually.

I tried 4 copies in a store before I found that was sharp in the corners, so there certainly is (or was - a few years ago now) significant copy variation.

I did use some AFMA to get the focus more accurate, and often it was accurate and I got nice sharp results.

The problem I had was that too often I would get erratic inaccurate focus (either OVF or LV), where photos would be quite soft (even in the centre) for no apparent reason. It did seem to be worse when used wide open at f2.8, but it wasn't exclusively f2.8.

So when it got the focus right, it was good, but too often was soft so I sold it. It did put me off 3rd party lenses a fair bit.

I have over the last few years read quite a few people seemed to have similar experiences with this particular Sigma lens (and an awful lot more with a range of other Sigma lenses), so I don't think it was an isolated case.

Colin

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DavidArmenPhoto Regular Member • Posts: 354
Re: The AFMA myth.

Andy01 wrote:

DavidArmenPhoto wrote:

Andy01 wrote:

I think that AFMA is useful in general, and can be EXTREMELY useful in some cases. I have tested every lens I have owned with 70D and 6D ii (the only two bodies I have owned with AFMA), and every one of them needed some degree of adjustment, often not major though. Lenses include Canon 24-105L, 24-105L ii, 100-400L, 100-400L ii & EF 35 f2 IS, and a Sigma 17-50 f2.8 (which I would rather not even talk about).

I do agree though that there are people here who blame every missed focus on AFMA (or lack of), and there are people here who seem to be much better than me in spotting front or back focusing (a recent example of an orca's fin that was not focused correctly - people spotted front focus on relatively calm reflective water, and suggested AFMA - better than me - AFMA may have been required or have helped, but it was pretty hard to tell from the image in question).

And a mention above of a couple of mm - a couple of mm can make all the difference when trying to shoot a bee in a flower at 400mm

Colin

What’s wrong with your copy of the Sigma 17-50? It’s a pretty sharp lens for its price actually.

I tried 4 copies in a store before I found that was sharp in the corners, so there certainly is (or was - a few years ago now) significant copy variation.

I did use some AFMA to get the focus more accurate, and often it was accurate and I got nice sharp results.

The problem I had was that too often I would get erratic inaccurate focus (either OVF or LV), where photos would be quite soft (even in the centre) for no apparent reason. It did seem to be worse when used wide open at f2.8, but it wasn't exclusively f2.8.

So when it got the focus right, it was good, but too often was soft so I sold it. It did put me off 3rd party lenses a fair bit.

I have over the last few years read quite a few people seemed to have similar experiences with this particular Sigma lens (and an awful lot more with a range of other Sigma lenses), so I don't think it was an isolated case.

Colin

Before I got the 17-50 I bought the sigma 50mm 1.4 ex dc and although I was and still am totally in love with the image quality, the focusing inconsistencies really put me off 3rd party for a while just like yourself. It wasn’t anything even sigma or canon could fix since it was both front and back focusing, and by different amounts each time; and I’d lose at least 30% of my shots to that inconsistency.
Didn’t buy another 3rd party for over a year til I got that sigma 17-50mm ex dc. I must say, when I got this lens about 8 months ago, it was pretty much the only sigma that I hadn’t heard focusing issues about, but I guess I hadn’t looked hard enough?
Anyway, the lens performed great from day one without any focusing problems at all and it also renders tones very very nicely. It even works flawlessly in live view, which is very rare for any sigma lens. I guess I got lucky and I’m glad haha

Sigma has always had really good lenses each with nice characteristics and amazing bokeh, it’s just too bad they suck at reverse engineering AF so much.

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