The AFMA myth.

Started 5 months ago | Discussions
Distinctly Average Contributing Member • Posts: 587
The AFMA myth.
16

It amazes me that time after time users of this and other forums suggest AFMA based on little or no evidence that it is needed. Users see a shot that is soft, or completely missed focus and instantly tell the OP that AFMA is required. Some fail to even understand the “M” in AFMA stands for”Micro” and not massive. Even when the focus was off by meters, people still sat “do AMFA on all your lenses”. Sometimes they do not even ask if the shot was taken through the viewfinder or using live view.

To me the above is bad advice. Firstly it is just not possible from a single shot taken out and about that AFMA is required. That can only be done with some proper testing. Next it often misses any diagnosis of what may or may not be wrong with an image. It happens all the time on these forums. I have even seen it given as advice then it was plainly obvious the softness was caused by motion blur.

For most users, especially if they are using Canon glass on their Canon bodies, AFMA is not required. Canon have even said in the past it is a bandage and not a permanent fix. AFMA is a good tool to have, but not something to be relied upon, nor something to fiddle with based on flimsy evidence. In a lot of cases it can confuse the user even more, especially those with little DSLR experience. The adjustments only make a few mm difference in the focus point, but this can be enough to make things look terrible. I know one chap who returned his camera three times for service and each time was told nothing was wrong but given a new body as a good Will gesture. It was only when someone (a Nikon rep, this was a Nikon camera) sat down with him for a few hundred shots that it was realised the AFMA advice coupled with his lack of knowledge that was causing the problem. The guy was ready to switch brands but is now a happy Nikon user, and his AFMA is set to zero on all his lenses.

I firmly believe we should only suggest AFMA after a lot of questions have been asked and some proper testing has been done. It is not the panacea it is made out to be.

Canon do have a good guide on AFMA - https://cdn.static-bl.com/images/manual/Canon-AF-Micro-Adjust-Guide.pdf but I do think it should start with a bit more info regarding when and why.

-- hide signature --
rmexpress22 Senior Member • Posts: 1,025
Re: The AFMA myth.
7

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.

 rmexpress22's gear list:rmexpress22's gear list
Canon EOS 5D Mark IV Canon EOS M6 Canon EF-M 22mm f/2 STM Sigma 85mm F1.4 Art Canon PowerShot G16 +14 more
RogerZoul
RogerZoul Senior Member • Posts: 2,445
Re: The AFMA myth.
5

Distinctly Average wrote:

It amazes me that time after time users of this and other forums suggest AFMA based on little or no evidence that it is needed. Users see a shot that is soft, or completely missed focus and instantly tell the OP that AFMA is required. Some fail to even understand the “M” in AFMA stands for”Micro” and not massive. Even when the focus was off by meters, people still sat “do AMFA on all your lenses”. Sometimes they do not even ask if the shot was taken through the viewfinder or using live view.

To me the above is bad advice. Firstly it is just not possible from a single shot taken out and about that AFMA is required. That can only be done with some proper testing. Next it often misses any diagnosis of what may or may not be wrong with an image. It happens all the time on these forums. I have even seen it given as advice then it was plainly obvious the softness was caused by motion blur.

For most users, especially if they are using Canon glass on their Canon bodies, AFMA is not required. Canon have even said in the past it is a bandage and not a permanent fix. AFMA is a good tool to have, but not something to be relied upon, nor something to fiddle with based on flimsy evidence. In a lot of cases it can confuse the user even more, especially those with little DSLR experience. The adjustments only make a few mm difference in the focus point, but this can be enough to make things look terrible. I know one chap who returned his camera three times for service and each time was told nothing was wrong but given a new body as a good Will gesture. It was only when someone (a Nikon rep, this was a Nikon camera) sat down with him for a few hundred shots that it was realised the AFMA advice coupled with his lack of knowledge that was causing the problem. The guy was ready to switch brands but is now a happy Nikon user, and his AFMA is set to zero on all his lenses.

I firmly believe we should only suggest AFMA after a lot of questions have been asked and some proper testing has been done. It is not the panacea it is made out to be.

Canon do have a good guide on AFMA - https://cdn.static-bl.com/images/manual/Canon-AF-Micro-Adjust-Guide.pdf but I do think it should start with a bit more info regarding when and why.

Amen!

No one is going to listen to you, however. Remember where this is posted.

 RogerZoul's gear list:RogerZoul's gear list
Canon EOS 7D Mark II Canon EOS 5DS R Canon EOS 5D Mark IV Canon EOS 90D Canon EF 500mm f/4.0L IS II USM +33 more
jrkliny
jrkliny Veteran Member • Posts: 4,109
Re: The AFMA myth.
4

I did detailed studies on 4 lenses on my 90d

No afma needed for any of them.

-- hide signature --
 jrkliny's gear list:jrkliny's gear list
Canon EOS 600D Canon EOS Rebel T6s Canon EOS 90D Canon EF 35mm F2.0 Canon EF-S 10-22mm F3.5-4.5 USM +7 more
DanInSoCal Contributing Member • Posts: 995
Re: The AFMA myth.
3

I wholeheartedly disagree, that AFMA is "useless".

I entered the Canon universe with a 30D. It did not have any in-body focus adjustment. I performed careful focus tests on my three lenses. While two of them were very close, the third -- the one I wanted to use the most -- was consistently back-focusing. I had no recourse but to send the body and lens to Canon for calibration. It came back, still back-focusing. I sent it back. It came back still back-focusing. I sent it back. They had CPS do the calibration. Finally it was usable (the errors after the first two "calibrations" were not subtle). This whole "adventure" took the better part of six weeks, and I had to pay all of the postage (and postal insurance), so this was not cheap. Hundreds of dollars.

When I upgraded to a 50D, I had a similar issue. For example I had a 70-200/4 IS that was consistently front-focusing on a test target. I was able to dial this in handily with AFMA, rather than spend weeks without a camera.

I will be the first to say that AFMA will only fix issues in a relatively narrow range; and that any "non-linear" behavior of the lens will need to be corrected either with Sigma/Tamron consoles or by sending lenses in to Canon (why Canon has not come up with a similar device, I simply don't understand -- they want the support $'s I suppose). But for "most" everyday minor front/back focus adjustments, AFMA is a godsend.

Regards,
Dan

OP Distinctly Average Contributing Member • Posts: 587
Re: The AFMA myth.
9

I have not said it is useless at all. Maybe re-read what I wrote. What I am suggesting is that it should not be the first thing to do as it is, especially with Canon lenses, rarely required. When someone on here looks at one OOF shot and says “your lens needs AFMA” then that is poor advice often leading the poor user down a rabbit hole of pain.

-- hide signature --
Dave
Dave Veteran Member • Posts: 4,951
Re: The AFMA myth.
1

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?

 Dave's gear list:Dave's gear list
Canon EOS 80D Canon EF 135mm F2L USM Canon EF-S 17-55mm f/2.8 IS USM Canon EF 100mm F2.8L Macro IS USM Canon EF 70-300mm f/4-5.6L IS USM +9 more
Cavig1 Contributing Member • Posts: 503
Re: The AFMA myth.
2
  1. Distinctly Average wrote:

I have not said it is useless at all. Maybe re-read what I wrote. What I am suggesting is that it should not be the first thing to do as it is, especially with Canon lenses, rarely required. When someone on here looks at one OOF shot and says “your lens needs AFMA” then that is poor advice often leading the poor user down a rabbit hole of pain.

Exactly!  It's not useless at all.  But it should be one of the last things tried (or recommended) rather than one of the first.

Almost all of the AF issues I see, here and with my own shots.  Are caused by other problems. Just sayin 🙂

Cavig

 Cavig1's gear list:Cavig1's gear list
Canon EOS 20D Canon EOS-1D Mark IV Canon EOS 70D Sony a6000 Canon EOS 7D Mark II +8 more
plantdoc Veteran Member • Posts: 3,587
Re: The AFMA myth.
4

AFMA is why I sold my Rebel cameras. I have 3 canon lenses that were never as sharp as expected. 100-400mk1, 70-200 f4, 15-85. I was able to take controlled test pics with 70d and compared OFV and LV. LV sharp, OFV NOT. AFMA to the rescue, but a time consuming nuisance. Test and correct software should be in the camera. Mirrorless is the real solution.

greg

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

jrkliny wrote:

I did detailed studies on 4 lenses on my 90d

No afma needed for any of them.

Same here. 6 lenses three are sigma. AND I’m a pixel peeper.

Not useless, but not everyone needs to do it.

 DavidArmenPhoto's gear list:DavidArmenPhoto's gear list
Canon EOS 90D Canon EF 85mm f/1.8 USM Sigma 50mm F1.4 EX DG HSM Sigma 30mm F1.4 EX DC HSM Sigma 17-50mm F2.8 EX DC OS HSM +3 more
jvc1 Senior Member • Posts: 1,714
Re: The AFMA myth.
3

I think you're being a little harsh. I'm pretty sure we read many of the same threads. For the most part, I see people recommending AFMA when you can see obvious front or back focusing in a posted image. only occasionally do I see someone suggesting it as the 1st thing someone should do.

Anyway, if someone is having consistent out of focus issues why shouldn't they check to see if AFMA will help?

-- hide signature --

I keep some of my favorite pictures here,
https://www.flickr.com/photos/129958940@N03/

 jvc1's gear list:jvc1's gear list
Canon EOS Rebel SL2 Canon EOS 90D Canon EF 85mm f/1.8 USM Canon EF-S 15-85mm f/3.5-5.6 IS USM Canon EF-S 60mm f/2.8 Macro USM +8 more
ThrillaMozilla Veteran Member • Posts: 4,317
Re: The AFMA myth.

jvc1 wrote:

I think you're being a little harsh. I'm pretty sure we read many of the same threads. For the most part, I see people recommending AFMA when you can see obvious front or back focusing in a posted image. only occasionally do I see someone suggesting it as the 1st thing someone should do.

I think the OP is referring to this thread, where it is the first thing that is suggested.  And sure enough, the guy takes the suggestion first thing, even though it's almost certainly not the problem.

I know this is a learning experience for all, but it seems like advice should be dispensed carefully, with a little more thought.

 ThrillaMozilla's gear list:ThrillaMozilla's gear list
Canon EOS Rebel SL1
OP Distinctly Average Contributing Member • Posts: 587
Re: The AFMA myth.

ThrillaMozilla wrote:

jvc1 wrote:

I think you're being a little harsh. I'm pretty sure we read many of the same threads. For the most part, I see people recommending AFMA when you can see obvious front or back focusing in a posted image. only occasionally do I see someone suggesting it as the 1st thing someone should do.

I think the OP is referring to this thread, where it is the first thing that is suggested. And sure enough, the guy takes the suggestion first thing, even though it's almost certainly not the problem.

I know this is a learning experience for all, but it seems like advice should be dispensed carefully, with a little more thought.

Indeed. It seems to happen quite frequently though and  I am sure it adds to the head scratching faced by many. There is a lot to learn whenever we get a new camera, lens or start out in a new hobby.

-- hide signature --
Adam2 Veteran Member • Posts: 6,855
Re: The AFMA myth.
1

AFMA involves calibrating the camera and lens at a specific distance and light source. As you indicated, it doesn't compensate for huge discrepancies and blantant mis-focus. When shooting through the pentaprism of an DSLR, the camera employs a phased detection array to detect edge contrast and focus the lens. No contrast edges --> no focus. For an explanation, see: https://photographylife.com/how-phase-detection-autofocus-works

rmexpress22 Senior Member • Posts: 1,025
Re: The AFMA myth.
2

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.

 rmexpress22's gear list:rmexpress22's gear list
Canon EOS 5D Mark IV Canon EOS M6 Canon EF-M 22mm f/2 STM Sigma 85mm F1.4 Art Canon PowerShot G16 +14 more
OP Distinctly Average Contributing Member • Posts: 587
Re: The AFMA myth.

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.

The thread is not about whether it is needed, more about how, why and when it should be done. It is about the advice given off the bat to AFMA instead of looking for far more likely issues.

-- hide signature --
EG
EG Regular Member • Posts: 315
Re: The AFMA myth.
2

Definitely not a myth. Some people’s standards are just lower, 

rmexpress22 Senior Member • Posts: 1,025
Re: The AFMA myth.
1

I responded to that in my first post in this thread. If someone describes something that seems like it could be remedied by AFMA I'm going to suggest AFMA. I don't have to ask 21 questions to arrive at the same recommendation. It's easy to see if it's user error, bad technique, or something that can use AFMA.

 rmexpress22's gear list:rmexpress22's gear list
Canon EOS 5D Mark IV Canon EOS M6 Canon EF-M 22mm f/2 STM Sigma 85mm F1.4 Art Canon PowerShot G16 +14 more
Andy01 Senior Member • Posts: 2,948
Re: The AFMA myth.
1

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

 Andy01's gear list:Andy01's gear list
Canon EOS M5 Canon 6D Mark II Canon EF-M 22mm f/2 STM Canon EF-M 11-22mm f/4-5.6 IS STM Canon EF 100-400mm F4.5-5.6L IS II +3 more
OP Distinctly Average Contributing Member • Posts: 587
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

I agree it can be useful. However a single shot is never really enough to say whether AFMA is needed unless it is a test shot. Another thread for instance where I saw instantly advice given to AFMA was one of people playing football (the proper one where you use you feet, not that silly padded takes a month to play one) where the poster had his cluster of focus points clearly on a player. However, right on the edge of those AF points was another player probably 8 feet nearer to the camera and the AF had locked onto that. Clearly that wan not an AFMA issue, but one three people suggested it was front focus that could be fixed that way.

-- hide signature --
Keyboard shortcuts:
FForum MMy threads