5D Mark IV focus problem.

[bavariancake]

I'm having the same issue with _two_ 5D IV bodies I bought together. I would describe it as:

- Inconsistent focusing that can't be cured with MFA, since the micro adjustment is as likely to cause a blurry shot as to improve another one

- Worse focusing with the large AF zones, especially the left and right thirds

- Generally front-focused when focused is missed

- Hit rate is only about 20% overall

- Live view gets perfect focus every time

- Focus not attributable to user error or lens field curvature - definitely producing unusable photos on a 24-70mm II at f/2.8. Effective resolution would be about 6-8MP.

I've sent both bodies in to Canon twice already. This second time around was more interesting, since the service manager and lead technician looked at the bodies.

They identified some AF issue they described as an interaction between the metering system and the AF system, and discovered a method to adjust this (unspecified) interaction.

When I received the cameras the 2nd time, I was able to get a 100% hit rate on about 30-40 shot on one body with the same test scenarios that would fail previously. After a couple of hours, I picked up the body again (after detaching/reattaching my 24-70 and battery), and the problem reappeared! The 2nd body appears to have the same issue without change.

I suspect an intermittent problem in the camera hardware - maybe a loose connector or optical component in the AF system.

Was anyone else able to get Canon Service to remedy the problem? Did they say what the cause was??

I may not be able to return the cameras since submitted the rebate for both already, so this is very frustrating. Hopefully everyone else was able to get this resolved!

 

[dgumshu]

I'm having the same issue with _two_ 5D IV bodies I bought together. I would describe it as:

- Inconsistent focusing that can't be cured with MFA, since the micro adjustment is as likely to cause a blurry shot as to improve another one

- Worse focusing with the large AF zones, especially the left and right thirds

- Generally front-focused when focused is missed

- Hit rate is only about 20% overall

- Live view gets perfect focus every time

- Focus not attributable to user error or lens field curvature - definitely producing unusable photos on a 24-70mm II at f/2.8. Effective resolution would be about 6-8MP.

I've sent both bodies in to Canon twice already. This second time around was more interesting, since the service manager and lead technician looked at the bodies.

They identified some AF issue they described as an interaction between the metering system and the AF system, and discovered a method to adjust this (unspecified) interaction.

When I received the cameras the 2nd time, I was able to get a 100% hit rate on about 30-40 shot on one body with the same test scenarios that would fail previously. After a couple of hours, I picked up the body again (after detaching/reattaching my 24-70 and battery), and the problem reappeared! The 2nd body appears to have the same issue without change.

I suspect an intermittent problem in the camera hardware - maybe a loose connector or optical component in the AF system.

Was anyone else able to get Canon Service to remedy the problem? Did they say what the cause was??

I may not be able to return the cameras since submitted the rebate for both already, so this is very frustrating. Hopefully everyone else was able to get this resolved!

I have a pair of 5D4's and have not had this problem. However, I use single point in AI servo for my needs, as large zone has never been as reliable in my other bodies as well.

 

[Nick5]

I did a quick/dirty micro focus adjustment for my 70-200 lens on my new 5D4. Got a -10, which was the same as on my old 5D3, so I felt confident. Went on a walk about and made about 50 shots at various settings. Most of the shots looked a little soft to me.

So I spent the last 3 hrs doing a serious MFA. Custom target, all distances measured twice. Camera as level and parallel as I can make it. Fired about 6 shots at each MFA setting of 0, -5, -10, +5, +10, plus live view. I set the lens to minimum focus distance or infinity before each auto focus. Used only the center focus point, which should be the most accurate. Even made a couple manual focus shots in Liveview at 10x with a loupe on the LCD. Used a heavy tripod, so no camera shake. All shots at 1/400 shutter speed, so no mirror slap vibration.

Found a problem, a big one I think. While accuracy could be achieved, repeatability was poor. I determined that -10 was my best MFA setting (for the max zoom of 200mm). So I made 20 identical shots at that setting, throwing the lens out of focus before each shot. Ten of those were thru the viewfinder, 10 with Liveview. In each batch, only 4 or 5 shots were OK. Close enough to the best reference shot to say they matched. But 5 or 6 of the bacth were not OK. Far enough off the reference to call it a bad focus.

I've had the 70-200 for over 10 years, used on 4 cameras. Used on a 5D3 for the past 4 years with no problems other than operator error.

So, has anybody else done any extensive focus testing? Any similar problems with repeatability? Are you getting better than a 50% success rate?

More power to you Redcrown.

I have never once even tried to Micro Adjust any of my gear as my "Need for Perfection" (Anal) would drive my crazy! ...............

 

[groupoid]

I have a 35/1.4 II, it's my only lens that needs AFMA (+6). The number is based on several FoCal tests, however, I never did them in really good lightning, and some of them reported inconsistent AF. My bedroom is not very well lit, and fluorescent doesn't help either. When I focus on random stuff in my bedroom, it may miss maybe 30% of shots. However, whenever focal gives an answer, it's +5 or +6 with very high curve fit (if you exclude clearly missed shots).

However, if I do tests (not focal, but just shooting a small high contrast objects many times) during the day with window blinds open, it's hard to complain. On a good target, the keeper rate is maybe 90%, and the 1 miss out of 10 would still be a the edge of DoF.

And if I go outside and focus, say, on car license plates, the keeper rate is also very high.

I only use center point for these tests. Spot AF, for some reason, is not very reliable. You probably need a very small contrast target such as bird's eye. I haven't used f/1.4 lenses before, it's hard to compare (of course, all tests are done on f/1.4). My guess is that there is always some possibility of user or camera error, sometimes without clear reason.

I was a bit paranoid about low light results and inability to get accurate FoCal, and even almost sent lenses to Canon. However, I read a little bit about AF system, and it seems that the procedure is as follows: the camera measures the "displacement" and sends the instructions to the lens motor, then the lens spins the motor, and then the camera takes a shot. There are two things that may go wrong:

1) Incorrect guess for the displacement by the camera.

2) Inconsistent execution or the instructions by the lens.

If it was the lens, then the level of inconsistency would not depend on the quality of light. My guess was that the camera sensors perform worse in bad lightning, which is something one would expect anyway.

 

[J A C S]

I have a 35/1.4 II, it's my only lens that needs AFMA (+6). The number is based on several FoCal tests, however, I never did them in really good lightning, and some of them reported inconsistent AF. My bedroom is not very well lit, and fluorescent doesn't help either. When I focus on random stuff in my bedroom, it may miss maybe 30% of shots. However, whenever focal gives an answer, it's +5 or +6 with very high curve fit (if you exclude clearly missed shots).

However, if I do tests (not focal, but just shooting a small high contrast objects many times) during the day with window blinds open, it's hard to complain. On a good target, the keeper rate is maybe 90%, and the 1 miss out of 10 would still be a the edge of DoF.

And if I go outside and focus, say, on car license plates, the keeper rate is also very high.

FoCal might be the problem. I have never seen a misfocused shot with my 35LII with the 5D2 and the 5D4, ever. No AFMA.

 

[groupoid]

FoCal might be the problem. I have never seen a misfocused shot with my 35LII with the 5D2 and the 5D4, ever. No AFMA.

Well, it's quite clear that my 35Lii needs AFMA (otherwise literally 100% shots are OOF). The numbers +5 and +6 seem very reasonable looking at the complete pool of data from FoCal. However, in my bedroom with bad lightning it does miss shots from time to time. I agree that it's suspicious because all other lenses do not need AFMA.

I thought it's just the limits of the camera, you can't get consistent AF at 1.4 in any lighting.

I guess the question I would like to ask: suppose that the keeper rate at daylight with good targets at 1.4 is close to 100%. Would it be safe to say that there are no problems? I had a feeling that most common focus defects would not be fixed by good lightning, is that correct?

My original guess on how the AF system works was, probably, an open-loop myth. In fact, Canon AF is most likely closed loop.

 

[J A C S]

FoCal might be the problem. I have never seen a misfocused shot with my 35LII with the 5D2 and the 5D4, ever. No AFMA.

Well, it's quite clear that my 35Lii needs AFMA (otherwise literally 100% shots are OOF). The numbers +5 and +6 seem very reasonable looking at the complete pool of data from FoCal. However, in my bedroom with bad lightning it does miss shots from time to time. I agree that it's suspicious because all other lenses do not need AFMA.

I thought it's just the limits of the camera, you can't get consistent AF at 1.4 in any lighting.

I guess the question I would like to ask: suppose that the keeper rate at daylight with good targets at 1.4 is close to 100%. Would it be safe to say that there are no problems? I had a feeling that most common focus defects would not be fixed by good lightning, is that correct?

Well, one would think so but the color temperature of the light may change not just the accuracy but may create tendency for back or front focusing. Canon did some changes to their AF sensors years ago and claim that this should not be happening but I have seen reports that it does. Maybe I am too lucky but I have not experienced it.

BTW, my 35L (not II) used to AF perfectly on my primitive, as they say, 5D2 which is for sale now.

 

[rxb dc]

It is always a bit curious that complaints about Canon cameras go up, especially with new posters with minimal history, and the spike in complaints tend to coincide with launch of new products by competitors.

Of course, it also could be that the recent rebates spurred new buyers for the 5D4 and they are still working though the adjustment phase.

 

[groupoid]

FoCal might be the problem. I have never seen a misfocused shot with my 35LII with the 5D2 and the 5D4, ever. No AFMA.

Could I also ask if the following is considered consistent? 5d4, 35L/1.4 II.

Tripod, de-focus before each shot. Center point one-shot AF, size of the square point is roughly the space between 53 and 55, blue line passes through the center of the focusing square.

The setup is not perfect, and there are couple of images with some BF, but the total focusing square is maybe half of DoF, so some error can be expected. Also, since there is some area below 54 which is in focus square, it may tend to focus a bit closer to the lens.

Am I right that there is literally nothing to worry about? Sorry about stupid question.

 

[J A C S]

Looks very good.

A slanted target is a really poor choice to check AF. Most of the time, the camera will front focus a bit. Test it on a flat target and not too close to you. It is harder to see DOF then but if the image is very sharp, you are OK.

 

[groupoid]

Also, the setup (pretty peasant). You can see the size relative to focus points.

 

[groupoid]

Looks very good.

A slanted target is a really poor choice to check AF. Most of the time, the camera will front focus a bit. Test it on a flat target and not too close to you. It is harder to see DOF then but if the image is very sharp, you are OK.

Thank you! I understand that this is not a perfect setup. Maybe the result can be improved with a better one. My goal was to find a reason to convince myself that there are no major flaws with the equipment, and the mistakes are more likely to be user error which can be fixed by skill.

 

[Nitzanmam]

Were you able to fix this issue?

I have the exact same problem with all my lenses.

 

[GreatWhiteWing]

Were you able to fix this issue?

I have the exact same problem with all my lenses.

I had dead nuts results from manual AFMA adjustments but poor results. Got Reikan FoCal and got much different and better results. I am a fan.

Reminds me about time to re-check

 

[Pocket Lint]

Were you able to fix this issue?

I have the exact same problem with all my lenses.

I had dead nuts results from manual AFMA adjustments but poor results. Got Reikan FoCal and got much different and better results. I am a fan.

Reminds me about time to re-check

I’ve spent a considerable amount of time reading up on various topics around micro-focus adjustment and doing my own thorough tests and came to the conclusion that the problem is inherent in the design of dSLR.



While you may not experience issues with micro-focus, some do, and it’s nice to have that option in camera to make micro-adjustments. I’ve only ever had a very slight issue with my 50L at close focus distance and wide open, which I determined to be about -11 adjustment. However, after all that testing, I realized, I never shoot in those conditions with that lens, and if I do, it’s easy to make an adjustment manually.



I’ve also found that making an micro-adjustment could affect the focus at other ranges and so I don’t use the adjustment at all.

 

[GreatWhiteWing]

Were you able to fix this issue?

I have the exact same problem with all my lenses.

I had dead nuts results from manual AFMA adjustments but poor results. Got Reikan FoCal and got much different and better results. I am a fan.

Reminds me about time to re-check

I’ve spent a considerable amount of time reading up on various topics around micro-focus adjustment and doing my own thorough tests and came to the conclusion that the problem is inherent in the design of dSLR.

While you may not experience issues with micro-focus, some do, and it’s nice to have that option in camera to make micro-adjustments. I’ve only ever had a very slight issue with my 50L at close focus distance and wide open, which I determined to be about -11 adjustment. However, after all that testing, I realized, I never shoot in those conditions with that lens, and if I do, it’s easy to make an adjustment manually.

I’ve also found that making an micro-adjustment could affect the focus at other ranges and so I don’t use the adjustment at all.

Interesting experience, thanks for the perspective. When I used FoCal my keeper rate for focus hits went way up. I tend to shoot kinds of subjects. One is landscapes and focus can be done meticulously using live view and zoom. My other (most often) mode is trying to capture just the right pose of 5-6 week old kittens which can be challenging for an AF system. Not the fastest subjects in the world but the pose/expression can be pretty fleeting. Got much better results after MFA. My wife is a pretty demanding client..lol

I agree the viewfinder AF design has challenges being off optical axis and what the sensor sees.

 

[webv555]

Were you able to fix this issue?

I have the exact same problem with all my lenses.

I had dead nuts results from manual AFMA adjustments but poor results. Got Reikan FoCal and got much different and better results. I am a fan.

Reminds me about time to re-check

I’ve spent a considerable amount of time reading up on various topics around micro-focus adjustment and doing my own thorough tests and came to the conclusion that the problem is inherent in the design of dSLR.

While you may not experience issues with micro-focus, some do, and it’s nice to have that option in camera to make micro-adjustments. I’ve only ever had a very slight issue with my 50L at close focus distance and wide open, which I determined to be about -11 adjustment. However, after all that testing, I realized, I never shoot in those conditions with that lens, and if I do, it’s easy to make an adjustment manually.

I’ve also found that making an micro-adjustment could affect the focus at other ranges and so I don’t use the adjustment at all.

Interesting experience, thanks for the perspective. When I used FoCal my keeper rate for focus hits went way up. I tend to shoot kinds of subjects. One is landscapes and focus can be done meticulously using live view and zoom. My other (most often) mode is trying to capture just the right pose of 5-6 week old kittens which can be challenging for an AF system. Not the fastest subjects in the world but the pose/expression can be pretty fleeting. Got much better results after MFA. My wife is a pretty demanding client..lol

I agree the viewfinder AF design has challenges being off optical axis and what the sensor sees.

Agree on above all, I give up and now adopt clicking using the LIVE view from main screen tapping, I know it was dead slow but I believe when the mirror is up you don't need AFMA adjustment!! correct me if I am wrong, noticed new modern mirrorless cameras don't have AFMA I think it is the same reason as I mentioned.

clicking via a screen is slow but I got perfect focus on some important clicks.

Reg

Vam

 

[GreatWhiteWing]

Were you able to fix this issue?

I have the exact same problem with all my lenses.

I had dead nuts results from manual AFMA adjustments but poor results. Got Reikan FoCal and got much different and better results. I am a fan.

Reminds me about time to re-check

I’ve spent a considerable amount of time reading up on various topics around micro-focus adjustment and doing my own thorough tests and came to the conclusion that the problem is inherent in the design of dSLR.

While you may not experience issues with micro-focus, some do, and it’s nice to have that option in camera to make micro-adjustments. I’ve only ever had a very slight issue with my 50L at close focus distance and wide open, which I determined to be about -11 adjustment. However, after all that testing, I realized, I never shoot in those conditions with that lens, and if I do, it’s easy to make an adjustment manually.

I’ve also found that making an micro-adjustment could affect the focus at other ranges and so I don’t use the adjustment at all.

Interesting experience, thanks for the perspective. When I used FoCal my keeper rate for focus hits went way up. I tend to shoot kinds of subjects. One is landscapes and focus can be done meticulously using live view and zoom. My other (most often) mode is trying to capture just the right pose of 5-6 week old kittens which can be challenging for an AF system. Not the fastest subjects in the world but the pose/expression can be pretty fleeting. Got much better results after MFA. My wife is a pretty demanding client..lol

I agree the viewfinder AF design has challenges being off optical axis and what the sensor sees.

Agree on above all, I give up and now adopt clicking using the LIVE view from main screen tapping, I know it was dead slow but I believe when the mirror is up you don't need AFMA adjustment!! correct me if I am wrong, noticed new modern mirrorless cameras don't have AFMA I think it is the same reason as I mentioned.

clicking via a screen is slow but I got perfect focus on some important clicks.

Reg

Vam

If what you are doing works for you that's great. From my meager understanding part of incoming image is diverted "down" via a mirror into the body where the AF sensor is

Here is an article from Canon on the subject. All that is eliminated in mirrorless as it uses the image on the sensor

https://www.usa.canon.com/internet/portal/us/home/learn/education/topics/article/2018/July/How-Does-Traditional-Digital-SLR-AF-Work/How-Does-Traditional-Digital-SLR-AF-Work