C300: DPAF substantially more reliable on the C100 than C300 MKII?

D

drummondb

Well-known member
I shot a wedding yesterday with both a C300/II and several C100s (both original and MKIIs). The experience reinforced my impression that the Dual Pixel Autofocus on the C300/II is much more complicated and much less reliable than it is on the C100.

I've used several C100 bodies with DPAF over the last 3+ years. Yes, the fixed box in the middle is limiting, but once you get used to it, I imagine most operators get quite adept at the constant dance you play. There's a lot of artful toggling and a fair bit of focus-and-recomposing. But it almost always works perfectly, in my experience--even when filming images which most would agree were underexposed.

When I had to use the C300/II yesterday, I was once again confronted with AF that was constantly freaking out, snapping from infinity to close focus and back again. I kept playing with settings (focus speed, responsiveness, box size, fixed or moveable, face priority, etc) to no avail. My takeaways were, no matter the AF settings in the menu, if the image was underexposed at all (according to the light meter bar on the LCD/EVF) there was a good chance the DPAF would freak out. If the images were not underexposed but face detect was set to priority, there was an even better chance the AF would freak out.

At the end of the night, I did extensive dance floor filming in a situation many might find familiar: dark backgrounds and LED party lights. The C300/II's DPAF was unreliable, freaking out again and again. I set everything to most closely match the DPAF operation on a C100 (large center frame only, no face detect). This did not help. I then picked up a C100/II, and it worked just fine, never freaking out at all.

I can post some examples, but I wonder, is my C300/II behaving oddly? Or is this par for the course? And does the C200 behave like this?
 
drummondb said:
I shot a wedding yesterday with both a C300/II and several C100s (both original and MKIIs). The experience reinforced my impression that the Dual Pixel Autofocus on the C300/II is much more complicated and much less reliable than it is on the C100.

I've used several C100 bodies with DPAF over the last 3+ years. Yes, the fixed box in the middle is limiting, but once you get used to it, I imagine most operators get quite adept at the constant dance you play. There's a lot of artful toggling and a fair bit of focus-and-recomposing. But it almost always works perfectly, in my experience--even when filming images which most would agree were underexposed.

When I had to use the C300/II yesterday, I was once again confronted with AF that was constantly freaking out, snapping from infinity to close focus and back again. I kept playing with settings (focus speed, responsiveness, box size, fixed or moveable, face priority, etc) to no avail. My takeaways were, no matter the AF settings in the menu, if the image was underexposed at all (according to the light meter bar on the LCD/EVF) there was a good chance the DPAF would freak out. If the images were not underexposed but face detect was set to priority, there was an even better chance the AF would freak out.

At the end of the night, I did extensive dance floor filming in a situation many might find familiar: dark backgrounds and LED party lights. The C300/II's DPAF was unreliable, freaking out again and again. I set everything to most closely match the DPAF operation on a C100 (large center frame only, no face detect). This did not help. I then picked up a C100/II, and it worked just fine, never freaking out at all.

I can post some examples, but I wonder, is my C300/II behaving oddly? Or is this par for the course? And does the C200 behave like this?
Click to expand...

Agreed. Used both a C100 and C300MKII on a shoot 2 days ago and was surprised at how much more responsive and reliable the AF was on the C100.
 
I've found the C300 II to be as reliable or more reliable. It is also nice because the C300 II gives you quite a bit more control including the fact that the manual focus assist guides will tell you whether the C300 II can actually sense enough contrast to tell where to focus.
 
I have years in on the C100 and C300 and recently bought the C200. I find the Face Detection requires contrast edges and a decent amount of light to work reliably. It doesn't like glasses, hats, bangs on people's faces so it can be limiting. I recently did a dance instruction series for a YouTube RED series, the dancers were performing on a white floor with a white BG. As long as I kept the dancers within exposure and contrast range for Face Detection, all was well. But when they started doing crazier drops to the floor and really fast and frantic movement, we switched the face detection off and just used the object tracking and or regular AF on them and it worked really, surprisingly well. I sense the DPAF is a bit different between the Gen 1 and Gen 2/3 cameras but I find on my C200, so far, it's pretty good. Same with rented C300 MKIIs. It's not perfect and it does freak out at times with low light and low contrast. I sometimes turn off the AF switch on the lens and if it cannot lock and use the focus guide for manual focus. Like any technology, it's not perfect. I also find the STM lenses work much smoother and better with DPAF. My 17-55 2.8 IS is much slower to AF than my 18-135 STM IS. Canon really should do a video shooter centric revamp of the stills lenses that video shooters rely on and give them ALL STM revisions, the 70-200s, 24-70, 17-55 should ALL be STM, although the 70-200 2.8 IS II is pretty responsive as is.
 
Last edited:
drummondb said:
Here's an example of what I mean: https://youtu.be/V23J5zgZFqQ

I have tons of C100/II footage from the exact same time and place, and it simply doesn't go crazy like this.
Click to expand...

In that case, I would not expect the DPAF to work well at all for the C300 II. To compensate, I would turn down the AF speed nearly all of the way and if I was using the continuous AF I would use it with slower response. Actually, I just wouldn't use continuous and would put it on one shot and wait for the manual focus guides to give you an indication that the camera can detect enough contrast to do an AF adjustment. Even when using continuous AF, I tend to use it more like one shot by keeping a button assigned to turn it off and keeping it off unless I absolutely need it. It would have been nice if Canon implemented an option to automatically turn off continuous AF whenever contrast was too low for the sensor ot make a precise adjustment.

I think the thing that the C100's single focus spot forces you to do is to reframe on a high contrast section of the face or shoulders before you hit the one shot AF. It also seems to have some type of lag or slower focus adjustment built in to keep it from freaking out in low contrast that you actually have to set in the C300 II's menus.
 
drummondb said:
Here's an example of what I mean: https://youtu.be/V23J5zgZFqQ

I have tons of C100/II footage from the exact same time and place, and it simply doesn't go crazy like this.
Click to expand...

Mostly underexposed/changing exposure multiple layers of faces, backs of heads with camera and subject movement, AF is the wrong tool here. I would set a zone and sweep the floor, manually changing focus or use one touch. IMHO, you're asking the camera to AF in a partly but mostly impossible situation. CPreston's suggestions are good too but in a difficult situation like this, either one touch or MF assist would work best.
 
I can show you an hour of C100 footage from the same time and place where the DPAF worked perfectly, and using an f/1.4 lens.
 
drummondb said:
I can show you an hour of C100 footage from the same time and place where the DPAF worked perfectly, and using an f/1.4 lens.
Click to expand...

Sounds like setting up / tuning the C300 II to perform more like the C100 as noted by cpreston could help?
 
You must log in or register to reply here.
Back
Top