5D3 Buffer + AF Question

I do not even know how to search for this strange issue…

My buffer appeared to be quickly filling (or acting very strangely) on my 5D3. I switched to MF and everything appears to functioning as it shoot (I can fire 20-23 mRAW files to a 400x card Transcend card). When I am in AF though, I can only fire 5-8 shots before the card slows.

What setting is causing this?

y u shoot mraw on 5diii?

Allan.L wrote in post #15600682
y u shoot mraw on 5diii?

LOL. For my purposes I don't need full size raw files (as much as the 5 terabytes of data I have love me)…

I'm probably wrong, but sounds like you didn't let the buffer clear before you started the burst-test in AF mode.

Burst buffer limits should not change between MF and AF assuming ISO doesn't change. Images shot at higher ISO will take up larger filesizes and that could/can eat into the buffer.

Glueeater wrote in post #15600689
LOL. For my purposes I don't need full size raw files (as much as the 5 terabytes of data I have love me)…

:p just messin'

But yes, did you perform the test and then switch it into AF to do the 2nd test too quickly? Give it some time to breathe.

I shot AF first and then MF. Buffer was clear - card removed and re-inserted.

Check the menu to see if you have "Long Exposure Noise Reduction" enabled, if so then set it to disable(or off) and try it again.

Mark, that setting is currently off on my camera still exhibiting same behavior.

I feel like an idiot, but I may have solved it:

AF2: AI Servo

AI Servo 1st Image Priority I had set to focus (as well as 2nd image priority)

Sorry for being a moron! Hopefully this helps a poor soul in the future.

LOL...Glad you got it solved

If you set focus priority in Servo AF, then you'd rather get more shots before the buffer fills than fewer. Servo AF can sometimes require a little more time between shots than One Shot AF or manual focus does. However, that means that your frame rate will decrease, which will cause your buffer to last longer. If the 5D Mark III is like my camera, you'll not get more shots, since when shooting RAW my camera doesn't empty the buffer in parallel with shooting, but it would at least last a longer time before it's full.

Anders, FYI I believe I incorrectly stated my issue previously. It must have not been a buffer issue but rather an actual actuation problem as my camera was attempting to assign AF priority before releasing the shutter. The menu I listed earlier was the culprit. I notice much more consistent firing with equal priority to release and focus and then 2nd image priority on release only.

This is a personal preference and I am not sure it is proper technique.

That being said, I think my buffer is just fine.

So it was just getting inconsistent and slow frames per second? My 7D does that when I have AF priority rather than shutter, like your settings would indicate. Glad you solved it.

Canon's cameras work (or have worked, the 1DX and 5D Mark III are a tad different) so, that when using Servo AF, you can set the camera to release priority. That implies that between every shot, the AF system gets one chance, and that's only one, to measure and compute desired lens focusing setting, send the focusing command to the lens and run the lens' AF motor once to correct the focusing error that's present. That's it. If any of these parts of the sequence failed, like couldn't measure distance properly, the image will be out of focus. But it will be taken.
Then you can set focus priority instead. If you do, the camera will try one AF attempt, but if that one fails, it may try a couple more times, to eventually either fail or succeed. Regardless, the picture is taken now too. Thus it may still be out of focus, but chances that it's in focus has increased, since more attempts to set focus are allowed.

The newest cameras have an intermediate setting too, but the principle is the same.
Thus, if you don't set priority to release, then the time between two shots could very well vary from one shot to another. That depends on the conditions for the AF to work with. Aim at a nice, black line across well lit white paper and it'll probably rattle away just as fast as with manual focus.

Hi Anders...That was going to be my second guess, and the third would have been the AA batteries in the grip issue.