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Author Topic: 1DX - Ai Servo Issue - Low light focus failure! Final Update 05/09/12  (Read 33380 times)

justaphotographer

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #30 on: July 28, 2012, 12:38:16 PM »
Hi Alex,

Hmmm this is very strange indeed.  I loaded your config file and AI-SERVO was great!  Then the only single thing I changed was to go from L to H and as soon as I did that AI-SERVO was horrible again.  I then changed back to L and once again it was near perfect.  I kept going back and forth and it was reproducible 100% of the time.  Yes let me give you more detail about my gear (don't have time just yet for uploading pictures though)

I tested this on multiple lenses. 50 1.2, 50 1.4, and 24 1.4 II.  I have yet to try my other lenses.  All behaved exactly the same in terms of how responsive the AI-SERVO was.

This might suggest something else is going on.  Although I still don't think it's hardware because clearly when I switch to L the AI-SERVO works great and when I switch back to H the AI-SERVO is bad again.  I am not sure why you are not seeing that or why I am not see what you are getting.  Hmmmm


Hi Mate,

Just tested your theory out - in my configuration where i know the camera will fail if i used the bugged out config - my fixed version works regardless of being on L or H.

Is it possible to upload an image regarding the scene/target that you are testing on? And please add what lenses you are using and/or have available to use so we can test with similar gear if possible :)

-Alex

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #30 on: July 28, 2012, 12:38:16 PM »

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #31 on: July 28, 2012, 12:40:38 PM »
Hi Alex,

Hmmm this is very strange indeed.  I loaded your config file and AI-SERVO was great!  Then the only single thing I changed was to go from L to H and as soon as I did that AI-SERVO was horrible again.  I then changed back to L and once again it was near perfect.  I kept going back and forth and it was reproducible 100% of the time.  Yes let me give you more detail about my gear (don't have time just yet for uploading pictures though)

I tested this on multiple lenses. 50 1.2, 50 1.4, and 24 1.4 II.  I have yet to try my other lenses.  All behaved exactly the same in terms of how responsive the AI-SERVO was.

This might suggest something else is going on.  Although I still don't think it's hardware because clearly when I switch to L the AI-SERVO works great and when I switch back to H the AI-SERVO is bad again.  I am not sure why you are not seeing that or why I am not see what you are getting.  Hmmmm


Hi Mate,

Just tested your theory out - in my configuration where i know the camera will fail if i used the bugged out config - my fixed version works regardless of being on L or H.

Is it possible to upload an image regarding the scene/target that you are testing on? And please add what lenses you are using and/or have available to use so we can test with similar gear if possible :)

-Alex

Mate I chucked everything on a tripod to make sure there was no funny business and You are correct L is fine H hunts...

I will report this on Monday.

neuroanatomist

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #32 on: July 28, 2012, 12:43:59 PM »
A troubleshooting suggestion. H and L frame rates are customizable (C.Fn3 menu).  What happens if you set H to 3 fps or L to 11 fps?  Can you ID a frame rate threshold for the problem?
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justaphotographer

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #33 on: July 28, 2012, 12:44:44 PM »
Oh not great, but great in that at least we are seeing the same thing.  This brings us closer to a possible cause and hopefully a solution by Canon.  Thank you so much for reporting this to Canon.  I would report it myself on Monday, but I will be traveling on assignment for couple of weeks.  If I can get a break in-between I too will report this.  I will however have access to the internet from my phone so I will check back in here in case you or anyone else has any updates on this issues.  Of course if I find out anything new myself I will report here so that everyone can benefit from this dialog.  Thanks Alex again for all your great help.

-Alex
[/quote]
[/quote]

Mate I chucked everything on a tripod to make sure there was no funny business and You are correct L is fine H hunts...

I will report this on Monday.
[/quote]

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #34 on: July 28, 2012, 12:46:02 PM »
A troubleshooting suggestion. H and L frame rates are customizable (C.Fn3 menu).  What happens if you set H to 3 fps or L to 11 fps?  Can you ID a frame rate threshold for the problem?

Will check in the morning and report back :)

Cheers for this!

justaphotographer

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #35 on: July 28, 2012, 12:47:14 PM »
Great question Neuro.  Yes I have ID a threshold (I tested each frames per second until I ran into the problem).  First of all though, the camera will not let you set L above H and vice versa.  However using H I have discovered the threshold is 10 fps.  That is to say 10 fps and lower seems to work well, but anything above that causes the AI-SERVO to have a melt down (ha!) in low light/contract.

A troubleshooting suggestion. H and L frame rates are customizable (C.Fn3 menu).  What happens if you set H to 3 fps or L to 11 fps?  Can you ID a frame rate threshold for the problem?

neuroanatomist

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #36 on: July 28, 2012, 12:51:28 PM »
With H at 12, L can be 11. Does the issue occur on L = 11 fps?
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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #36 on: July 28, 2012, 12:51:28 PM »

justaphotographer

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #37 on: July 28, 2012, 12:53:02 PM »
Yes with L at 11 the problem does occur.  The problem only disappears when either H or L is at 10 fps or below.

With H at 12, L can be 11. Does the issue occur on L = 11 fps?

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #38 on: July 28, 2012, 01:00:05 PM »
Yes with L at 11 the problem does occur.  The problem only disappears when either H or L is at 10 fps or below.

With H at 12, L can be 11. Does the issue occur on L = 11 fps?

So logically the sampling rate that the light meter feeds scene information to the servo isn't large/fast enough under low light to sufficiently provide data to the AF. I can't get anyone at canon to explain how the light meter is tied to the new af let alone the sampling rates, however going by the findings tonight that would be my initial thought as to what is going on

justaphotographer

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #39 on: July 28, 2012, 01:07:21 PM »
By the way, so everyone knows...I HATE this kind of stuff.  I never come online unless I have a problem I need to solve.  Like all of you I'm sure, I would totally rather be just doing my job as a photographer, but when you come across a problem like this that actually affects your work and how you work, it causes me to want to find a solution.  Hence my search here where I discovered others who saw the same exact problem as I.  I know nothing is perfect, but I just wish this wasn't such a big problem.  I'm a photojournalist who shoots in very low light very very often so this is a problem that I actually ran into while on assignment so it has real world consequences.

Just wanted to let everyone know I sure wish we could just forget all this and just focus on picture making.  However, this is a pretty big issue that has to be addressed.  I can let go of a great deal and accept a number of faults, but this seems like something Canon need to address for a camera of this class and price.
« Last Edit: July 28, 2012, 01:08:55 PM by justaphotographer »

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #40 on: July 28, 2012, 01:13:55 PM »
By the way, so everyone knows...I HATE this kind of stuff.  I never come online unless I have a problem I need to solve.  Like all of you I'm sure, I would totally rather be just doing my job as a photographer, but when you come across a problem like this that actually affects your work and how you work, it causes me to want to find a solution.  Hence my search here where I discovered others who saw the same exact problem as I.  I know nothing is perfect, but I just wish this wasn't such a big problem.  I'm a photojournalist who shoots in very low light very very often so this is a problem that I actually ran into while on assignment so it has real world consequences.

Just wanted to let everyone know I sure wish we could just forget all this and just focus on picture making.  However, this is a pretty big issue that has to be addressed.  I can let go of a great deal and accept a number of faults, but this seems like something Canon need to address for a camera of this class and price.

Totally agree !

I had the camera for <36 hours and stumbled on it... I have spent the last 3 weeks wracking my brain trying to work it out so I feel very fortunate that You noticed it so quickly. I have had to carry a back up body in fear of the AF playing up in situations I couldn't afford the af to be playing up in :/

Will keep this updated with any updates from Canon.


justaphotographer

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #41 on: July 28, 2012, 05:51:57 PM »
In doing a few more tests I still have to say (even with the camera set to the lower 10 fps setting) AI-SERVO is nowhere near the advertised -2 EV.  For instance when I set my camera to ONE-SHOT in 0 to -2 EV light the camera bangs focus perfectly.  However, even set at the lower 10 fps in AI-SERVO under the same light condition, the camera fails to focus in that same light.  It is certainly better than when it is set to 12 fps, but still cannot focus at 0, -1, or -2 EV light in AI-SERVO mode.

Can others confirm this?  The short of it is that I don't really trust this camera to focus track in low light/contrast.

A big shame because this camera blows away anything I've ever used.  It is just that good in every other respect.  People say it's not that much different than the 5D3, but owning both I disagree.  It is on a whole other planet from the 5D3.  Don't get me wrong the 5D3 is a fantastic camera, but can't touch the 1Dx in nearly every area (including the AF).  They share similar 61 AF system, but it isn't fully the same.

Really, the troubling low light/contrast AI-SERVO problem is really the only weakness I see with this camera.  If it didn't affect the way I shoot I would just forget about it and move on.
« Last Edit: July 28, 2012, 08:53:38 PM by justaphotographer »

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #42 on: July 28, 2012, 09:50:42 PM »
In doing a few more tests I still have to say (even with the camera set to the lower 10 fps setting) AI-SERVO is nowhere near the advertised -2 EV.  For instance when I set my camera to ONE-SHOT in 0 to -2 EV light the camera bangs focus perfectly.  However, even set at the lower 10 fps in AI-SERVO under the same light condition, the camera fails to focus in that same light.  It is certainly better than when it is set to 12 fps, but still cannot focus at 0, -1, or -2 EV light in AI-SERVO mode.

Can others confirm this?  The short of it is that I don't really trust this camera to focus track in low light/contrast.

A big shame because this camera blows away anything I've ever used.  It is just that good in every other respect.  People say it's not that much different than the 5D3, but owning both I disagree.  It is on a whole other planet from the 5D3.  Don't get me wrong the 5D3 is a fantastic camera, but can't touch the 1Dx in nearly every area (including the AF).  They share similar 61 AF system, but it isn't fully the same.

Really, the troubling low light/contrast AI-SERVO problem is really the only weakness I see with this camera.  If it didn't affect the way I shoot I would just forget about it and move on.

It's not only you - reception hall - weddings and runways is where I am fearing it will fail.

With that said - I can confirm -2ev single shot af lock no real issues. Ai-Servo stops working a long time before that, however - it needs contrast to see the target, - 2ev is rather dark I at-least the scenario i created - I could barely see anything moving with my own eyes (the black af points don't help here either) let alone the camera being able to see any contrast at those light levels.

I owned a 2x5d3's for a short while and i didn't really put the unit through the paces as I did with the 1dx - yes its a whole other planet in terms of speed, there is no comparison between the two bodies. The single chip solution really lags the 5d3 (and tbh 5 fps is really more like 3 on the 5d3 with the same configuration i have my 1DX set at 12fps with no noticeable drop in fps). I the IQ between the two bodies esp at hi-iso is no comparison at least in my eyes.

From a technical standpoint the af points on the 1DX and 5D3 are very-very small. More suited to afpoint-to-target point to point hand off under normal light.

In comparison to nikons offering where the center af cluster are enlarged af points - low light -2ev targeting is much easier (only thing i had to compare was a d800) where the nikons offering locked 8/10 attempts where the 1DX locked 5/10 attempts. At -1ev the the canon was much faster and hit 10/10 (and about 50% faster to lock then the d800)

With that's said useable single shot on the 1DX is -1.7-1.8ev D800 really drops off around -1-1.2ev (for the time it takes to lock reasons)

But there was absolutely no difference in 3d tracking vs single shot on the nikon where the 1DX drops off a long time before that.

I can't re-run the same tests as I dont have access to a d800 anymore but I would be interested to see if the same test run in Ai-Servo L with return the same results.

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Re: 1DX (possible) Ai Servo Issue - Sort of - Fixed! UPDATE 27/07
« Reply #42 on: July 28, 2012, 09:50:42 PM »

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Re: 1DX (possible) Ai Servo Issue - Low light focus failure! UPDATE 31/07
« Reply #43 on: July 31, 2012, 06:23:20 AM »
Replicated issue with a brand new 1DX at the store I bought mine from. It's not isolated as I had hoped - staff can't believe it either.

Waiting on Canon now

Peter Dawson

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Re: 1DX (possible) Ai Servo Issue - Low light focus failure! UPDATE 31/07
« Reply #44 on: July 31, 2012, 09:10:57 AM »
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

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Re: 1DX (possible) Ai Servo Issue - Low light focus failure! UPDATE 31/07
« Reply #44 on: July 31, 2012, 09:10:57 AM »