1DX - Ai Servo Issue - Low light focus failure! Final Update 05/09/12

[Sycotek]

I would just like to thank all the members that have contributed to this thread.  I'm sure, like me, there are many 1D X owners and soon to be owners following your updates with interest.
I speak for all of us when I say that we appreciate the time you take to post your findings.
Thank you
Peter

Hopefully it's isolated and clearly it wont affect everyone as we all shoot in different conditions.

But for those that it does effect - if they could just make note and say if they noticed the issue then we can estimate how wide spread the problem is.

I would love it if its only a handful of bodies - less issues for canon.

In all honesty I was hoping the new shop unit would not show the issue so I could just swap them over and get on with my job.

[hammy]

Do you have problem trying to select the AF point with the multi-controller? It's not responsive with my 1Dx. Let me know if you have the same problem. I'm wondering if it's just my 1Dx or it's the same with all 1Dx

thanks

[Sycotek]

Do you have problem trying to select the AF point with the multi-controller? It's not responsive with my 1Dx. Let me know if you have the same problem. I'm wondering if it's just my 1Dx or it's the same with all 1Dx

thanks

I can't say I have that issue - however You need to enable it - if you haven't then turn the unit on - hit [Q], custom config, select multicontroller (bottom right) and set it to af selector.

[Viggo]

Do you have problem trying to select the AF point with the multi-controller? It's not responsive with my 1Dx. Let me know if you have the same problem. I'm wondering if it's just my 1Dx or it's the same with all 1Dx

thanks

I can't say I have that issue - however You need to enable it - if you haven't then turn the unit on - hit [Q], custom config, select multicontroller (bottom right) and set it to af selector.

Great work keeping this thread alive, maybe Craig could push this issue out on the front page and stir it up also? Seems like this really needs all the attention it can get.

I'm still a tad mad for the silence from Canon on the 1d3 issues, so let's hope this isn't one of those things. They have been more open lately, let's hope they started a new way with that and keep it up!

Thanks!

[neuroanatomist]

@Sycotek and other affected users:  Question on settings - how are the AI Servo 1st and 2nd Image Priority set?  Obviously, with Release priority and Shooting speed priority, OOF shots could be taken.  The manual indicates with Equal priority for the 2nd image, shooting may slow down.  Have you tried setting it to Focus priority for 1st and 2nd?  If it's set to the default (equal priority), I wonder if the camera is inappropriately weighting the shutter release over focus?

[Charles_cz]

What is the best way to bring Canon's attention to this issue. Obviously this issue affects more than just few units (mine included) and I am sure a lot of people are not aware of this yet.

 Any official channels to report bugs and problems with 1D X?  I am positive they will fix it with firmware update.

                   Charles

[Sycotek]

@Sycotek and other affected users:  Question on settings - how are the AI Servo 1st and 2nd Image Priority set?  Obviously, with Release priority and Shooting speed priority, OOF shots could be taken.  The manual indicates with Equal priority for the 2nd image, shooting may slow down.  Have you tried setting it to Focus priority for 1st and 2nd?  If it's set to the default (equal priority), I wonder if the camera is inappropriately weighting the shutter release over focus?

The stock 1DX was used as straight out of box (we were watching the flickering green light to signify no focus lock)
My 1DX is set to 1st frame af priority (will not release without af lock)

Watch the green light flicker - easy to see that its out of focus that way. We got the store unit to even halt the lens as it does on mine.

I am in contact with Canon Australia's National Account Manager - and one of the heads of CPS Australia (so I have come to realise)

Since isolating the issue I haven't heard back other then I was jumping the gun a little. I have sent further proof (stock unit repeated issue) and no response as yet - but they do take a few days to get back to Me. Hopefully tomorrow - Although seeing as we tried to warn them prior to the oly games they may wait till its over before bringing it to light.

[Richard Lane]

Thanks for bringing these issues to everyones attention. 

I compared One Shot Mode, against the new 1DX AI Servo III and the 1DMKIV AI Servo II using the Canon 85mm f/1.8 set to the standard default Case 1 tracking. I was able to replicate the lack of AF in AI Servo in very poor light, with a low contrast stationary subject.  The way I was able to simulate this test was by hanging a gray towel over the shower curtain bar in the bathroom.  The test was performed during the day, so I was getting some ambient light coming down the hallway since there was a window about 15 ft away.  I left the light off in the bathroom and then I stood just outside of the bathroom doorway.  So, I was actually just standing in the hallway.

With the 1DX, I took a shot at the center of the gray towel in One Shot and the camera was able to achieve focus lock and the ISO was 25,600.  I then took a shot of the towel in AI Servo and the 1DX wouldn't AF on the towel.  The shot was blurry and out of focus.  I also tried to shoot the edge of the towel in AI Servo, but the camera still wouldn't Auto-focus.

I then repeated the test exactly the same way with the 1DMKIV and I got the same exact results.  In One Shot the MKIV locked in on the gray towel and it was clearly in focus, despite giving up an approximate 1-stop advantage to the 1DX.  Then I switched to AI Servo for the MKIV and the camera would not AF on the towel and the shot was definitely blurry.

So, it seems to me that this is not necessarily an issue isolated to the 1DX only.  One thing that I would note is that I would never use the camera this way, under these conditions.  If I were taking a static shot like this I would switch to One Shot, which can easily be added to the DOF or Multi-2 button.  Since AI Servo is optimized for movment and tracking, perhaps Canon has made a trade-off here and they have sacrificed AI Servo sensitivity for static subjects in "low light with "low contrast." Perhaps movement or motion of the subject would further assist the performance of the 1DX and 1DMKIV in AI Servo?  I would also like to add that I have never had any issues tracking athletes in dark uniforms in poorly lit stadiums with the MKIV at ISO 12,800.  I have not tried the 1DX yet under these conditions.

I think it would be rare that I would be shooting "static subjects" under such "poor lighting", with such "low contrast" while using AI Servo. However, if others find themselves in this situation, then I would switch to One Shot Mode.  AI Servo and One Shot have been optimized for their strengths and weaknesses in individual shooting situations, if they weren't then we would only have one choice.  The 7D has AI Focus which is a hybrid mode between One Shot and AI Servo, if your subject was standing still then it would shoot in One Shot mode, if your subject moved then it would switch to AI Servo mode, but it wasn't as good as either mode used separately, so that is probably why Canon has not incorporated AI Focus mode into the 1D series.

I noted that some users above were also trying to track a low contrast subject walking around the house in poor lighting, also noted was the blurry wedding photograph which did have some contrast, and as far as I'm concerned is completely unaccepatble in decent lighting like that. 

Would I like this to not be an issue?  Of course!  Would it be nice if we could have AI Servo perform better under these condtions?  Absolutely! 

If Canon could improve this by increasing the sensitivity of AI Servo at an ISO of 25,600 that would be cool too, however the downside may be that AI Servo would become very skittish and cause the AF to jump around with the slightest movement of the subject, which may then have other ramifications.  As the OP and Canon has mentioned, perhaps some tweaking of the custom AF cases and sensitivities will help improve this situation.

Rich

[Sh1n1ng Forc3]

This appears to be a very low light/low contrast issue.  I took my 1DX in Ai Servo, 4 point expansion into my bathroom with the door closed and window blocked as to only allow in the smallest amount of light (simulating moonlight conditions at -2ev).  There I attempted to focus in Ai Servo as if I was trying to lock onto a subject in low light that needed tracking.  In my test I was actually very impressed with my 1DX.  I shot this static image with my 50mm F/1.2 at 1/2000, F/1.2 and ISO 51,200.  I kept the shutter speed high to simulate the speed I use to stop action even in low light.  The camera was able to lock focus on the high contrast and shiny sink however if I tried to lock focus on either the soap bottle or lotion bottle which flanked the sink it failed no matter the distance from the subjects.  I put it in L and H shooting speeds and this made no difference for me.  All in all I am pleased with this cameras low light focus and tracking ability as it has been put to use in some local band gigs around the Seattle area with fantastic results.

For information purposes my 1DX serial is 042XXXXXXX31.

[Richard Lane]

Thanks for the info!

I just did some additional quick testing with the 1DX to see if this situation was due to high ISO (in dim light) or low contrast or both.

It seems that in AI Servo, even at ISO 100 with the low contrast gray towel (in the bathroom), AI Servo was still unable to focus on the towel. Of course, One Shot was no problem even at high ISO's and low contrast as stated in my post above.

However, when I focused on the white shower curtain, which is some type of embroidered floral lace  (don't ask), the 1DX was able to focus on the medium contrast (lace cloth pattern) shower curtain even at 25,600 in AI Servo.

So, it does seem to be more of low contrast issue rather than a high ISO AI Servo issue.

Rich

[Sh1n1ng Forc3]

I foolishly left off the most important part of my test above.  While the 1DX would focus on the chrome sink at -2ev while in Ai Servo and could not focus on the two low contrast/low light bottles on either side, when I placed the camera in single shot (using a single press with DoF Preview button as configured to change drive mode) the camera immediately locked onto both bottles when asked.

This confirms that the 1DX is clearly more capable of acquiring focus when in single shot vs Ai Servo although my experience has been that Ai Servo is still very good in low light for me.  I have not seen my 1DX act in a manner similar to the OP's or the wedding shooter. 

I believe that while in Ai Servo the camera is relocating computational resources/power to "other" factors that drive the focus acquisition algorithms making it more nimble but less able to grab initial focus in low light/low contrast situations.  If this is the case this should be able to be adjusted through a firmware update which can adjust the algorithms/methods and resources to allow the camera to achieve similar results as found in single shot (but at what cost?).  This leaves me with more questions than answers unfortunately.

[Sycotek]

Thanks to all that have attempted to re-create this:

It's a given that the unit will not focus on -2ev low light via Ai-servo, that's only where the investigation started, if anythig the servo has issues around 1ev.

The real issue initial target lock (first frame) failing under low light - low light as in a normal light in a normal room trying to lock on a face.

7D has Ai-focus which I never use - I was comparing Ai-servo against the 1dx Ai servo. With that said the 7D af points are 4 times as large so target acquisition should be faster by default in low light.

I digress: try working in a normal room with an over head light and try locking on a persons face at 3fps and at 12fps with all points on and first point priority and attempt to lock on the targets face (say 180-200mm from 2m away). Now try an notice just how much faster 3fps is in terms of the af points "dancing" on the targets face.

At 12 fps majority of the time it drives my lens and locks up - if I rack the lens to 0 and attempt to focus the lens won't even rack... At 3-10fps the lens racks (actually tries to focus and gets a lock)

Standard 60w light in a 4x4 room isn't exactly low light ESP considering my gf is white skinned with dark hair and eyes.

The 7D regardless of frame rate gives me the initial lock immediately under the same conditions.

[Richard Lane]

I digress: try working in a normal room with an over head light and try locking on a persons face at 3fps and at 12fps with all points on and first point priority and attempt to lock on the targets face (say 180-200mm from 2m away). Now try an notice just how much faster 3fps is in terms of the af points "dancing" on the targets face.

At 12 fps majority of the time it drives my lens and locks up - if I rack the lens to 0 and attempt to focus the lens won't even rack... At 3-10fps the lens racks (actually tries to focus and gets a lock)

Standard 60w light in a 4x4 room isn't exactly low light ESP considering my gf is white skinned with dark hair and eyes.

The 7D regardless of frame rate gives me the initial lock immediately under the same conditions.

I'm not following what you are trying to point out or test?
Are you talking about AI Servo?  I guess that you mean AI Servo, since the AF points don't dance around in One Shot.
 
AI Servo requires the subject to change distance?

On my test if I understand you correctly, both frame rates at high speed and low speed seem to dance around similarly and if I had to pick one, I would say that the 12fps actually dances around more, but I'm not sure what you're trying to convey?

My camera had no problem focusing in AI Servo with a small light on.

The focusing limitations previously were related to low contrast in AI Servo with a subject that is not changing distance, and the low light worsened the situation.

[Sh1n1ng Forc3]

Thanks to all that have attempted to re-create this:

It's a given that the unit will not focus on -2ev low light via Ai-servo, that's only where the investigation started, if anythig the servo has issues around 1ev.

The real issue initial target lock (first frame) failing under low light - low light as in a normal light in a normal room trying to lock on a face.

7D has Ai-focus which I never use - I was comparing Ai-servo against the 1dx Ai servo. With that said the 7D af points are 4 times as large so target acquisition should be faster by default in low light.

I digress: try working in a normal room with an over head light and try locking on a persons face at 3fps and at 12fps with all points on and first point priority and attempt to lock on the targets face (say 180-200mm from 2m away). Now try an notice just how much faster 3fps is in terms of the af points "dancing" on the targets face.

At 12 fps majority of the time it drives my lens and locks up - if I rack the lens to 0 and attempt to focus the lens won't even rack... At 3-10fps the lens racks (actually tries to focus and gets a lock)

Standard 60w light in a 4x4 room isn't exactly low light ESP considering my gf is white skinned with dark hair and eyes.

The 7D regardless of frame rate gives me the initial lock immediately under the same conditions.

I hear what you are saying but my 1DX doesn't have problems locking on target at -1ev like yours while in Ai Servo.  It only has issues at extremely low light coupled with low contrast with a static object.  12FPS works just fine for me in Ai Servo as I cannot reproduce your specific issue.  This leads me to believe there is something else going on here.  Perhaps a bad batch from Canon, but I cannot say.  All I know is what I have posted above.

[Sycotek]

I digress: try working in a normal room with an over head light and try locking on a persons face at 3fps and at 12fps with all points on and first point priority and attempt to lock on the targets face (say 180-200mm from 2m away). Now try an notice just how much faster 3fps is in terms of the af points "dancing" on the targets face.

At 12 fps majority of the time it drives my lens and locks up - if I rack the lens to 0 and attempt to focus the lens won't even rack... At 3-10fps the lens racks (actually tries to focus and gets a lock)

Standard 60w light in a 4x4 room isn't exactly low light ESP considering my gf is white skinned with dark hair and eyes.

The 7D regardless of frame rate gives me the initial lock immediately under the same conditions.

I'm not following what you are trying to point out or test?
Are you talking about AI Servo?  I guess that you mean AI Servo, since the AF points don't dance around in One Shot.
 
AI Servo requires the subject to change distance?

On my test if I understand you correctly, both frame rates at high speed and low speed seem to dance around similarly and if I had to pick one, I would say that the 12fps actually dances around more, but I'm not sure what you're trying to convey?

My camera had no problem focusing in AI Servo with a small light on.

The focusing limitations previously were related to low contrast in AI Servo with a subject that is not changing distance, and not necessarily a low light issue, although that doesn't help the situation.

Hi Richard, Thanks for replying

The original issue was the Ai Servo and contrast in low light - correct, there is a definite discrepancy between ai-servo and one shot ability to focus on objects in low light - but the reason for it being an major issue (to me anyway) is you can't track what you can't lock onto initially: if the lens doesn't rack or the lens racks to infinity and stops when trying lock onto an object - stationary or otherwise - then you can't track that object to start with. Example - this initial became apparent when trying to track my cousin moving around the house, with a fair amount of house lights on.

My camera exhibits this issue in lighting conditions that it should have no issue in (the 7D for example locks regardless) - same as justaphotographer and the in-store demo unit. However that inability to lock onto the target isn't noticed when enabling 10 fps or lower, there is no issue with re-racking the lens and the af points move over the object at a noticeably higher rate then at 12 fps.

I do apologise for the confusion - I hope this is a little clearer.