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

[Sycotek]

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Update 05/09/12
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Finally got an answer for this guys: It's a feature...

CPS London via CPS Australia:

"On the first issue of AF tracking in low light. Everything you found was correct and the camera needs to be dropped back to 10fps to AF in the lowest light conditions. At 10fps the camera can focus fast and effectively @ -2 Ev Level but at 12fps the Ev Level is changed to -0.5 Ev. This is because of the light reduction when the mirror moves at that speed. The camera does this automatically. This is what you were experiencing under the conditions of the cat walk. This is comparable to all professional 35mm products out there on the market"

On a side note: does the picture below with the 10 and 12 fps comparison even remotely look like 0ev let alone -2EV ?

Anyway - since I hadn't heard from Canon, chasing it up every day I actually switched over to a D4 setup after a mishap with the 1DX and AF assist (bug 2) at a reception - and haven't been happier - I don't have these limitation anymore. It's less a lottery and more consistent frame to frame shots, low light is substantially better AF and i can actually see what i am focusing on - finally.

Anyways hopefully this will help the PJ's understand what is happening.

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Update 21/08
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Still no word from Canon regarding the findings. However they have replaced the my body - I now have a body starting with SN 05 rather then 04.

So changing nothing but FPS L to 10 FPS I ran a very simple test:

So 2nd unit, brand spanking new and exhibits same issue.

If this body doesn't have a bug with the 70-200 f2.8 II/600EX combo, I'll put up with not being able to use 12fps and hope they fix it via firmware update.

Although a month with no reply is just bad form from Canon.


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Update 31/07
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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

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Update 29/07
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Issue has been isolated to anything more then 10 fps when shooting in low light - Initial target lock is hindered and at times target subject can not be locked on (lens racks to infinity and stops) - af servo tracking is reduced by 80% in some instances the af tracking stops completely.

And by low light I mean - my testing area is a 60w equivalent cfw room light, 4mx4m room and my girlfriends face (porcelain skin dark eyebrows and dark eyes plenty of contrast). In direct comparison my trusty 7D locks on and tracks without issues.

Setting the servo between 3 and 10 fps fixes the issue on the 1DX

Many thanks to justaphotographer for isolating this issue.

Have reported to Canon - waiting to see a resolution - for now set fps to 10 or less.



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Update 27/07:
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OK so speaking with Canon We have isolated it down to an AF function/modification. It doesn't seem to be a custom function change.

I tend to use case 1 and case 4 and modify case 4 (all sliders moved to the very left) - now I can't seem to figure out what combination of changes make the AF balls up. I had everything set as I like it last night but the second i changed over rotation to computer only (as i tend to shoot portrait mode) the af started to play up. Undoing the rotation change did not fix the issue. Had to reset to a working backup.

If I leave the af setting as stock default everything works properly.

And as it has always been this only shows up in low light Servo.

If anyone is interested I can load a broken config they can play around with and see if they can work it out.

It's a little frustrating as I don't know what I am changing that's causing the AF to bug out. As proved to me when I was shooting with canon in and underground car park the 1DX could lock onto a black car moving at 20+ km/hr in next to no light and get a ridiculously sharp image.

Canon is working on it, as am I - keep keep this updated.


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Ok so for all those not wanting to read everything here is the conclusion:

Sat with Canon Australia Pro Support this afternoon - which they came to my work after My work hours, sat down for a coffee, gave me a few tips and fixed my problem - I really could not ask for more support from any company! And remember they are from a completely different state then I!!!

Anyways after being schooled on some af config case tweaks we took the cameras into an underground carpark probably a good -1 to -2ev at least.

They tested their camera no issue - passed it to me and it blew me way snap bang locked no issues. They grabbed mine and it went ass up - they couldn't believe it.

Went through all the settings and couldn't work out what it is. So we copied the working 1Dx's config on a memory card and loaded it on mine and it's like a brand new camera - it's like night vision tbh.

So yeah if you are having issues as per below - grab this config file: https://dl.dropbox.com/u/33440790/DXSave/WORRKSSS.CSD and load it.

Canon will get back to me as we are unsure if its something funky in the settings or setting screwed up something in servo logic. Either-way I will update this as soon as I am made aware.

Thank You Canon Australia for taking care of Me

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Not looking to bag out the DX - actually looking for help from other owners and or Photographers that can explain this phenomenon:

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Issue: Low light Ai Servo mis-focus/no-focus
Full-size images here: https://dl.dropbox.com/u/33440790/weirdservo.zip (65MB)

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1 body – 1DX
3 Lenses – ef50 f1.4, 24-105 F4 L, 70-200 f2.8 II
Shot in Jpeg – all options on (ALO, NR, Lens Correction etc…) and then all options off.
All handheld (no tripod av)
--

I’ll preface this with; on the night prior I was out shooting under moonlight – without any notable issues – with, of all lenses - the ef 50 f1.4 (which if you know and love the lens, you know it hunts focus in low light). With my short time with the 1DX , my impressions of the 1DX’s AF is that it snaps to focus on objects You cannot physically see and locks on with near-possessed speed.

Now last night I found this issue when trying to track my cousins head/face moving through the house. It wasn’t particularly dark 3 room lights registered iso 1600-3200 f2.8 can’t remember the shutter speed. She got sick of being target practise so I turned to my dog. The 1DX wouldn’t grab focus either.

By this I mean it racks the lens to infinity and stops or just stops AFTER it’s visibly passes focus. Not and MFD issue either – after a slight mini panic attack, I swapped over lenses and same issue, swapped to the prime and exact same issue. Thought it was the changes I made to case 4 so swapped it to a default case 1 – same issue. I haven’t played around with 1st and 2nd frame preference but I then swapped it to focus preference and still no change.

Intrigued from my experiences the night before I swapped it to [One Shot] and it focused and locked on with possessed speed once again. Swap back to [Ai Servo] and it racks to infinity/racks past.

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So in the original room there were too many variables of people moving through the house changing the light so I setup a pretty average testing area:

This was [One shot] 24-105 at [email protected], 1/40, iso 25600

This was [Ai Servo] – same settings. Just failed to focus.

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Shot from the other side of the room:

This was [One shot] 24-105 at [email protected], 1/25, iso 25600

This was [Ai Servo] – same settings. Just failed to focus.

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So then I thought let’s bring in 3 times more light (even with the f4/5.6 crosstypes more light can’t be a bad thing)

This was [One shot] EF 50 f1.4 at [email protected]/40, iso 3200 (bottom af point from memory)

This was [Ai Servo] – same settings. Just failed to focus. (iso 4000)

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So finally I thought it was a contrast issue – so added more contrast:

This was [One shot] EF 50 f1.4 at f2 @1/40, iso 6400

This was [Ai Servo] – same settings. Just failed to focus

--

I thought the Servo using ITR then needed more light so turned off ITR and it had the same issue.

I’m out of ideas for explaining this one.

Please note: I shot and tried all AF modes to acquire lock via [Ai Servo]. [One Shot] locked on with any AF mode selected.

 

[robin]

Re: 1DX (possible) Ai Servo Issue

What kind of priority setting do you use? No I don't have the dx, yet, but I had same with 1D Mark4 some time ago..

 

[drjlo]

Re: 1DX (possible) Ai Servo Issue

Well, going by my 5D III AI Servo, I would say AF can be unpredictable, simply missing focus under certain circumstances, often in low light and depending on lens. Then again, at other times that seem "difficult," it has no problem focusing with AI Servo.

As usual, if AF lock is crucial, I use One shot. With 1DX price point, I would have thought it would be much better than 5D III though.

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

Well, going by my 5D III AI Servo, I would say AF can be unpredictable, simply missing focus under certain circumstances, often in low light and depending on lens. Then again, at other times that seem "difficult," it has no problem focusing with AI Servo.

As usual, if AF lock is crucial, I use One shot. With 1DX price point, I would have thought it would be much better than 5D III though.

This was just AV mode nothing special.

I'm still waiting on canon's response. I did further testing and seems to crap out on a certain grey point (from my testing) blue or red or white target in the same low light and there was next to no issues

Single shot does lock down to the rated -2ev (tested with a light meter) didn't think at the time to test where the servo craps out at.

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

Further testing:

I don’t think the 100K rgb sensor is quite as refined as it should be.

I tested this theory over lunch with a red, blue, brown, grey dark box (so to speak) – focused on the canon black cap using the canon logo as target:

[One Shot] - 1/50 f4 at 105mm iso 25k – found that it is 2-4x faster on [one shot] with iTR on and locked on without issues – I removed iTR just to make sure it wasn’t interfering.

[Ai Servo] - 1/50 f4 at 105mm iso 25k - fails to lock and racks the lens to infinity.

[Ai Servo] 1/80 f4 at 105mm iso 25k - I replaced the black cap with a silver eclipse mint container and it locked on instantly with [One Shot] and [Ai Servo] it also had no issues locking onto red, blue and white either.

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I was having issues one shot - locking on grey objects at -2ev (which is sort of expected) adding in a white and red object made it easier but it still wasn't a cakewalk do to the af points not lighting up and not being able to see where the af point was in correlation to the target. I had to use a tripod and a torch to make sure I had the af point on the object... otherwise i had to keep moving the af point back and forth just to be able to see where the point was...

 

[Mt Spokane Photography]

Re: 1DX (possible) Ai Servo Issue

Further testing:

I don’t think the 100K rgb sensor is quite as refined as it should be.

I tested this theory over lunch with a red, blue, brown, grey dark box (so to speak) – focused on the canon black cap using the canon logo as target:

I was having issues one shot - locking on grey objects at -2ev (which is sort of expected) adding in a white and red object made it easier but it still wasn't a cakewalk do to the af points not lighting up and not being able to see where the af point was in correlation to the target. I had to use a tripod and a torch to make sure I had the af point on the object... otherwise i had to keep moving the af point back and forth just to be able to see where the point was...

I'd exchange the camera myself. There are many testers and users who haven't reported a issue like this. As for the unlighted AF points, that is a big issue, part of the reason I returned my 5D MK III and bought a 1D MK IV.
BTW You can light up the points by pressing the AF point selection button, but its not a elegant work around. You certainly do not need a torch.

 

[neuroanatomist]

Re: 1DX (possible) Ai Servo Issue

Let us know what Canon says.

Oddly, in the 6 use cases designed to make setting up the AI Servo options, 'still life' isn't one of them. Just wondering if that's the best test scenario for an AI Servo issue?

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

Let us know what Canon says.

Oddly, in the 6 use cases designed to make setting up the AI Servo options, 'still life' isn't one of them. Just wondering if that's the best test scenario for an AI Servo issue?

I actually only started to look into this as i couldn't lock onto my cousins head moving around the house... definitely wasn't still - i just needed a controlled environment for testing however so this the above is what I came up with.

Regarding the need for a torch - i found when i lit up all the af points i then couldn't see the target lol but that af selector light up all points is something I have done since my 7D Agreed not elegant but it works.

 

[AlbertaCanonShooter]

Re: 1DX (possible) Ai Servo Issue

I've been having focus issues with the 1D X in both AI Servo and one shot.

I also had similar experiences in full daylight as the OP with the camera refusing to focus at all. In my case, I was using a 70-200 2.8IS II L. A few times when I would point the camera to an object at infinity. The focus would rack to the nearest distance and stop. This was in sing;e shot AF. It wouldn't hunt - it would just go totally out of focus. Releasing and pressing AF wouldn't do anything - the camera would not try to focus again. The only ay I could get it to acquire focus was to manually focus the lens (to get it at least somewhat sharp), then the AF would begin working again.

Below is one example of the camera missing focus from a wedding I shot this past weekend. An assistant was holding a 600EX-RT behind the couple for backlighting. This was in one shot mode with single AF point and four expansion points. This is a screen grab from the file in DPP so the active (and helper) focus point can be seen. As you can see, there is lots of contrast for the main focus point, as well as good contrast under the four expansion points yet it totally missed.

Here's the OOF example from the wedding:

 

[neuroanatomist]

Re: 1DX (possible) Ai Servo Issue

Although I'm having a problem with the 1D X not storing AFMA settings, AI Servo focusing in low light seems fine. ISO 4000 shot, screenshot of 50% view in DPP.

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

I've been having focus issues with the 1D X in both AI Servo and one shot.

I also had similar experiences in full daylight as the OP with the camera refusing to focus at all. In my case, I was using a 70-200 2.8IS II L. A few times when I would point the camera to an object at infinity. The focus would rack to the nearest distance and stop. This was in sing;e shot AF. It wouldn't hunt - it would just go totally out of focus. Releasing and pressing AF wouldn't do anything - the camera would not try to focus again. The only ay I could get it to acquire focus was to manually focus the lens (to get it at least somewhat sharp), then the AF would begin working again.

Below is one example of the camera missing focus from a wedding I shot this past weekend. An assistant was holding a 600EX-RT behind the couple for backlighting. This was in one shot mode with single AF point and four expansion points. This is a screen grab from the file in DPP so the active (and helper) focus point can be seen. As you can see, there is lots of contrast for the main focus point, as well as good contrast under the four expansion points yet it totally missed.

Here's the OOF example from the wedding:

Ok so I am not the only one - I am meeting with canon Pro Services tomorrow as they want to test out my camera personally and for me to test out another unit.

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Did a runway shoot last night:

Whilst the lighting condition were far from perfect it was enough to get 1/250 f4 iso 3200-5000 images through the camera. Case 1 this time – with tracking sensitivity ‘locked on’ to -2.

However… I could not use iTR all points on af tracking as it would fail to lock majority of the time, I have been trying my best to make use of this mode as in good light - it is excellent.

Ended up having to use my standard 4 point expansion method (by far the most accurate and predictable AF) which I lost one outfit due to the camera refusing to grab focus of the model – orange dress plenty of skin and black hair for contrast. I generally aim for the line between the collarbone and the start of the outfit for the camera to be able to grab something.

Wasn’t overly high profile shoot so impact to Me is limited, but not impressed with the outcome.

Pre-show I was aiming at people at the end of the runway which had a white wall, they were in darkish clothing, others were in grey and even some in wacky multi colours – white skin, dark hair – plenty of contrast and it wouldn’t lock in Servo, Single shot no issues :/

Not sure how we can emulate this on tomorrow with canon – but these are the conditions I was worried it would be failing in.

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

Although I'm having a problem with the 1D X not storing AFMA settings, AI Servo focusing in low light seems fine. ISO 4000 shot, screenshot of 50% view in DPP.

Your sample has plenty of contrast that wouldn't effect the af - I actually ran a second set of controlled issues for canon:

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Configuration:

-Using the same scene as the original controlled data (with the toy from the first set) but adding another room light to make it easier on the camera. 2 lights this time, no-where near pushing the AF’s limits (I didn’t have a light meter on me so couldn’t confirm exact EV – but we know single shot stuffs at exactly -2ev and one shot AF here was nice and snappy)

-One Shot under all tests/af modes snapped to focus instantly – no re-racking, no hesitation.

-I had to set 1st frame AF release to equal priority (2nd frame is still on its default equal priority) as it wouldn’t fire due to not being able to get focus of the subject with 1st frame focus priority.
-I had my Auntie wear something blue/red/white – which would provide ample contrast (so we can’t blame it on being black/grey etc)

-This was shot under a custom CASE 4 with tracking sensitivity set to -2 – it was retested with standard CASE 1 with no difference in the results.

Testing Methodology:

-4 one shot images taken at set markers on the ground followed by a series of Ai Servo images, this was done for manual af point (one point), 4point af expansion and 12 point - zone af. I attempted this with 61 points but it would lock on the wall regardless of where I put the initial AF point marker in Ai Servo mode. The images below are taken from DPP with AF point on and info in the middle (information exposed from the Ai Servo shot). The comparison Ai Servo image was use where my Auntie crossed over near or on the single shot reference image – She was walking a moderate pace for the Ai Servo shots.

Quick Comparison:

First Frame, Manual AF Point (One Point)

-One Shot on the left, Ai Servo on the Right.
-1/100, f4, iso 25K

Mid Frame, Manual AF Point (One Point)

-One Shot on the left, Ai Servo on the Right.
-1/100, f4, iso 25K

End Frame, Manual AF Point (One Point)

-One Shot on the left, Ai Servo on the Right.
-1/80, f4, iso 25K

Example of what happens when you can’t lock onto the target on first frame – Manual AF Point (On Point)

So I moved on to AF Expansion – for this I targeted the t-shirt hoping it would have a chance with the 4 extra points to lock onto face and shoulders.

First Frame, 4 point AF expansion:

-One Shot on the left, Ai Servo on the Right.
-1/100, f4, iso 25K

Mid Frame, 4 point AF expansion:

-One Shot on the left, Ai Servo on the Right.
-1/80, f4, iso 25K

End Frame, 4 point AF expansion:

-One Shot on the left, Ai Servo on the Right.
-1/80, f4, iso 25K

Example of what happens when you can’t lock onto the target on first frame – 4pt AF Expansion

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It's very obvious its a contrast issue, I just don't know how to go about fixing/circumventing it

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

I've been having focus issues with the 1D X in both AI Servo and one shot.

I also had similar experiences in full daylight as the OP with the camera refusing to focus at all. In my case, I was using a 70-200 2.8IS II L. A few times when I would point the camera to an object at infinity. The focus would rack to the nearest distance and stop. This was in sing;e shot AF. It wouldn't hunt - it would just go totally out of focus. Releasing and pressing AF wouldn't do anything - the camera would not try to focus again. The only ay I could get it to acquire focus was to manually focus the lens (to get it at least somewhat sharp), then the AF would begin working again.

Below is one example of the camera missing focus from a wedding I shot this past weekend. An assistant was holding a 600EX-RT behind the couple for backlighting. This was in one shot mode with single AF point and four expansion points. This is a screen grab from the file in DPP so the active (and helper) focus point can be seen. As you can see, there is lots of contrast for the main focus point, as well as good contrast under the four expansion points yet it totally missed.

Here's the OOF example from the wedding:

What is your serial number start with (first 4 digits) we can possible compare or pm me the full one and ill send you mine

 

[bdunbar79]

Re: 1DX (possible) Ai Servo Issue

Wow, that's actually pretty terrible. You don't even see that with the 1D Mark IV; it locks on in very low contrast in AI Servo.

 

[DarkG]

Re: 1DX (possible) Ai Servo Issue

hey guys.... thanks a lot posting these tests............ I am waiting for my 1DX but now I am a bit like

 

[robin]

Re: 1DX (possible) Ai Servo Issue

Sorry to hear about these problems, but this does not seem to be usual. I have got 3 1DX yesterday and checked all three, and none has these issues. We did a lot of tests, because we are leaving for Olympia tomorrow, and you can guess we did not need any problems with new cameras there (bad enough that we got them "in the last minute"..

 

[howhigh]

Re: 1DX (possible) Ai Servo Issue

Although I understand there are some differences between the 1DX and the 5D3 AF, I think it might be worth noting, that the 5D3 has the same issue (at least mine has. low light servo tracking = not possible (one shot works)).

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

Although I understand there are some differences between the 1DX and the 5D3 AF, I think it might be worth noting, that the 5D3 has the same issue (at least mine has. low light servo tracking = not possible (one shot works)).

Thank You for this input - I returned my 5D3's so I couldn't test myself - I was curious if it would effect them too.

Maybe it's just a *feature* I'll need to learn to live with.

Will keep you guys posted when I meet with canon this afternoon.

 

[bbasiaga]

Re: 1DX (possible) Ai Servo Issue

Obviously not an expert here, but I wonder if there is some pre-act/PID type algorithm in the AI servo software where by its reading info from the AF sensor and trying to 'predict' the motion of the target before it moves the lens to the focus point. With no movement, it get no info, it makes no change....If there is just not enough light for it to accurrately calculate movement, the same outcome would occur as in these test cases where the target is not actually moving.

I have seen some behavior like this out of control loops in production facilities I have worked in. Most of the time the software can be tuned to stop the issue.

-Brian

 

[Sycotek]

Re: 1DX (possible) Ai Servo Issue

Obviously not an expert here, but I wonder if there is some pre-act/PID type algorithm in the AI servo software where by its reading info from the AF sensor and trying to 'predict' the motion of the target before it moves the lens to the focus point. With no movement, it get no info, it makes no change....If there is just not enough light for it to accurately calculate movement, the same outcome would occur as in these test cases where the target is not actually moving.

I have seen some behavior like this out of control loops in production facilities I have worked in. Most of the time the software can be tuned to stop the issue.

-Brian

possible - however you need to assign a target for the cameras first af point priority. You need that to lock regardless or it doesn't know what you are pointing at what colour or face to register and track.

The camera failed to lock on for me on a runway/catwalk which has plenty of movement.

Furthermore the second set of test i put up were single shot vs moving target ai servo - in these instances the camera failed to lock on the target correctly and ended up with everything out of focus.

Agree'd it could be software/firmware fixed and hopefully thats all it is!