C100: Just bought a C100 Mark ii - issues with Facial Detection AF - submitted to Canon

iggy097

iggy097

Well-known member
Hey all, long time user of the C100 Mark i - just bought a Mark ii - I have 3 STM lenses that I thought would get good use of the Facial Detection.
First shoot I did - footage is ruined. The image pulses at the edge of the screen constantly with the Facial Detection turned on. I called Canon this morning and submitted the video I did this morning replicating the issue. Canon will call back when they view it, but they said it was not normal.
Tired two different STM lenses, hand held, tripod, IS off, IS on - same result.
Issue only occurs with Facial Detection on - if I turn it off and just run Continual AF - no issues.
Latest firmware on the C100.
I'll attach the videos - anyone else heard of this?

 
I see it, that's weird. Definitely a mechanical or software issue, it shouldn't do that. Update us on what you find out from Canon and if they fix it in a timely manner. Neither my C200 nor the C300 MKIIs I rent have done this.
 
I used face detection on the Canon C100 II approximately twice until I realized that it was junk compared to the continuous. I came to the conclusion (not verified) that the face detection doesn't actually use the DPAF at all. It just uses standard phase detection, so hunting, slow focus, and focus on high contrast rather than the face is a major problem. My guess is that your nearly infinite depth of field lens is allowing the phase detection continuously focus near to far as it attempts to optimize your dark hair against the white background. It could be an issue with the lens programming as you would think that Canon would have programmed in some type of algorithm to reduce continuous hunting with stm lenses, but maybe not. I'm guessing this is normal behavior based on the design system.
 
cpreston said:
I used face detection on the Canon C100 II approximately twice until I realized that it was junk compared to the continuous. I came to the conclusion (not verified) that the face detection doesn't actually use the DPAF at all. It just uses standard phase detection, so hunting, slow focus, and focus on high contrast rather than the face is a major problem. My guess is that your nearly infinite depth of field lens is allowing the phase detection continuously focus near to far as it attempts to optimize your dark hair against the white background. It could be an issue with the lens programming as you would think that Canon would have programmed in some type of algorithm to reduce continuous hunting with stm lenses, but maybe not. I'm guessing this is normal behavior based on the design system.
Click to expand...

Noticing the same thing myself - Canon is still looking into it.
 
I used it on one of my shoots yesterday - I can still use the footage - because it wasn't critical
 
Ouch. Glad it's still usable. TBH I'm not sure I would have noticed the pulsing if you hadn't pointed it out but it IS there...
 
Iggy,

I don't know if you saw it or not but at 2:22 there appears to be an angry mop moving around the bottom of the frame. Looks unnatural. ;)
 
I have had great success removing focus pulsing by applying warp stabilizer in premiere pro.

interested what the reaction from canon will be.
 
Canon said they have never seen that issue before. They are having me send it in for service. Very helpful on the phone. Only had the camera for a week, hopefully the issue is resolved.
 
Have you tried this without wearing glasses? Just a shot in the dark, but a majority of the time I've found facial recognition doesn't initialise when subjects are wearing eyeglasses on my C300ii. Doesn't pulse unless my focus box is over something plain with no detail/contrast.
 
NMSK said:
Have you tried this without wearing glasses? Just a shot in the dark, but a majority of the time I've found facial recognition doesn't initialise when subjects are wearing eyeglasses on my C300ii. Doesn't pulse unless my focus box is over something plain with no detail/contrast.
Click to expand...

Yea - had a few different shots the day prior with talent not wearing glasses. Same thing.
 
I have a C100mkII and a C200. It seems to me that you have two issues that interact. First, focus hunting and second focus breathing.

The issue of hunting has already been discussed in this thread and, yes, the C100 only uses DPAF in the centre (so, not for face tracking). However, the complaint is about focus breathing: where the angle of view changes when the lens is focussed. This will happen on any camera.

So, try this test. Set up a scene with a focus point in the foreground and another farther away. Put each of your lenses on the camera and rack focus between them while watching the composition. Focus breathing will be more or less evident depending on the lens (and if it is a zoom, the focal length).

So the problem is likely in the design of the lens (not the camera) and any focus shift will need to have this effect masked. The fact that the camera is fixed and autofocus is hunting just makes the problem visible.

Your solutions are to use a lens that breaths less (or not at all $$$), to keep a fixed focus for this kind of shot using DOF, to introduce camera movement so the edges of the scene are moving and the breathing is not noticed, or to try to fix it in post. You will need to do one of these any time you want to rack focus.
 
mikemilton said:
I have a C100mkII and a C200. It seems to me that you have two issues that interact. First, focus hunting and second focus breathing.

The issue of hunting has already been discussed in this thread and, yes, the C100 only uses DPAF in the centre (so, not for face tracking). However, the complaint is about focus breathing: where the angle of view changes when the lens is focussed. This will happen on any camera.

So, try this test. Set up a scene with a focus point in the foreground and another farther away. Put each of your lenses on the camera and rack focus between them while watching the composition. Focus breathing will be more or less evident depending on the lens (and if it is a zoom, the focal length).

So the problem is likely in the design of the lens (not the camera) and any focus shift will need to have this effect masked. The fact that the camera is fixed and autofocus is hunting just makes the problem visible.

Your solutions are to use a lens that breaths less (or not at all $$$), to keep a fixed focus for this kind of shot using DOF, to introduce camera movement so the edges of the scene are moving and the breathing is not noticed, or to try to fix it in post. You will need to do one of these any time you want to rack focus.
Click to expand...

Canon actually took a look at the video and they had never seen anything like it. They tried to reproduce with the same camera/lens setup and were unable so they think it's software or hardware related. They had me 2 day air it in for service as it's a brand new camera. I'll keep the thread updated.
 
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