C100: My dual pixel auto focus doesn't work consistently on third-party lenses

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drummondb

Well-known member
Anyone else seeing this? Dual pixel AF works great with my Canon glass, but I’m having trouble with my Sigma 27-70 and my Sigma 18-35mm 1.8.

Sometimes it works with the Sigmas, and sometimes it doesn’t. And I can’t figure anything out to get it working again once it stops. I’ve tried: turning the camera on and off, taking the battery off, taking the lens off, toggling the AF switch on the lens, toggling the focus lock button, and changing the auto focus method in the C100 menu.

I do have the focus lock option mapped to button 15, the one-shot AF button under the lens mount. Could that cause any problems?
 
drummondb said:
Anyone else seeing this? Dual pixel AF works great with my Canon glass, but I’m having trouble with my Sigma 27-70 and my Sigma 18-35mm 1.8.

Sometimes it works with the Sigmas, and sometimes it doesn’t. And I can’t figure anything out to get it working again once it stops. I’ve tried: turning the camera on and off, taking the battery off, taking the lens off, toggling the AF switch on the lens, toggling the focus lock button, and changing the auto focus method in the C100 menu.

I do have the focus lock option mapped to button 15, the one-shot AF button under the lens mount. Could that cause any problems?
Click to expand...

I tried a Sigma 105/2.8 a couple of weeks ago. Like other Sigma/C100 user reports, AF only worked when the iris was fully open (ie 2.8 with that lens.) I emailed Sigma and they weren't interested , saying they can't guarantee functionality with the C100. Try it with yours. My guess is that will be your problem.

The lens went back and was exchanged for an L series 100.

Ben.
 
Yup. All my Sigma glass would only engage AF with the lens wide open. This was the one-shot since dual-pixel wasn't available at that point. I had the 50/1.4 and 30/1.4 and both did this. I too called Sigma and got the same response that they really don't support the C cameras. Pretty bad. I sold them and moved to Canons.
 
I do feel that we've been asking for lawn mowers for the last X years, and now have asked these lawn mowers to perform on a race track.

Guessing, Canon knew about the technology - they probably invented it - and started making lenses work with it. 24-105 is okay, 100mm Macro is better, 18-135 is bloody quick. Sigma? Tamron? No. They weren't in that meeting. I also found this dichotomy when shooting with the FS100/700 with Metabones adaptor. Basically, the best behaved lenses were eMount, and Sigmas on a powered Metabones EF adaptor were rather iffy. Well done Samyang for ignoring all this and putting a stepless iris and a toothed focus ring on their cine lenses.

But then again, Sigma's AF was never its strong point.
 
Remember, those are third party lenses, NOT Canon. They are reverse engineered. They have no first hand access to Canons technology and Canon doesn't care if their lenses work with Canon cameras. Unfortunately, if you want something that's guaranteed to work properly, then you will have to buy the Canon lenses that they say all work with the feature.
 
Can anyone explain why all those Sigma lenses are working just fine with the Canon 70D dual pixel AF? I have the 18-35mm and it works MUCH better (at any f-stop) than any Canon lens I have tried...and I ve tried many! (STMs are the only ones being slightly better I thing). I hope the next Cxxx will be working just fine with every lens. I believe there is still something missing from the dual AF upgrade for the C100 and thats why there are not more options for AF (like moving the focus point for example). I hope everything the 70D can do now will pass to the next C...
 
I just dont understand why Canon didnt add relocating the Dual Pixel focus target to this upgrade. It would really add a lot of functionality.
 
The way that Canon describes the upgrade makes me think that relocating the focus target is impossible. They make it sound like the Dual Pixel design only exists in the center of the sensor. Even the pictorial of the sensor upgrade makes it look that way. This is just a guess, though.

You're right, though. I don't even consider the upgrade to be worthwhile without being able to change the location of the auto focus. I can rarely think of a time where my focus point is in the center of the sensor.
 
cpreston said:
...I don't even consider the upgrade to be worthwhile without being able to change the location of the auto focus. I can rarely think of a time where my focus point is in the center of the sensor.
Click to expand...

I was skeptical at first, too. But I'm won over now. You can always engage the focus lock and recompose.
 
Just picked up a Tamron 24-70 2.8, though disappointed to find that my C100's AF doesn't play so well with it. Works fine for a few seconds after booting up the camera or initiating lens lock, but then just quits AF after. Bummer since I had chosen the Tamron over Canon's equivalent due to the Tamron's Vibration Control.

That said, I've found the C100 AF upgrade very convenient to use, especially on interviews with a slider. The center frame AF area is a slight hinderance, but can be worked with once you learn how to work with it (invaluable for steadicam, for instance.
 
dcarstens said:
Just picked up a Tamron 24-70 2.8, though disappointed to find that my C100's AF doesn't play so well with it. Works fine for a few seconds after booting up the camera or initiating lens lock, but then just quits AF after. Bummer since I had chosen the Tamron over Canon's equivalent due to the Tamron's Vibration Control.

That said, I've found the C100 AF upgrade very convenient to use, especially on interviews with a slider. The center frame AF area is a slight hinderance, but can be worked with once you learn how to work with it (invaluable for steadicam, for instance.
Click to expand...


Did you try shooting at f/2.8? Apparently the AF only works at the widest aperture on Sigma glass at least. Not sure about Tamron.
 
Dual Pixel AF (surprisingly) seems to be working with my Tokina AT-X Pro I 28-70mm f/2.8 at any aperture, though it's not as smooth as any of my USM or STM lenses from Canon. Yet another reason that this lens is a great buy.
 
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