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1D X Mk II not changing exposure in bursts when in One Shot AF mode


When I set aperture priority, AI servo, and High Speed continuous drive and shoot bursts, the shutter speed changes as the camera is pointed to differently lit subjects. Every frame is properly exposed.


However, when autofocus is changed to One Shot, and I shoot bursts of the same subjects, there is no change in shutter speed - it remains at the value it was for the first shot of the burst.


I'm guessing that shouldn't occur. It seems that exposure lock is happening in that situation.


So is that due to a setting I inadvertently set (I hope)?

Does the camera need a reset (clearing all camera settings didn't work)?

Is this a known issue?







You seem to have the winning solution!


CanonCommunity one, canon techs zero.







View solution in original post



I don't think I fully understand your situation, with one shot AF mode are you panning to the different subjects while continuing the burst?  If so and you are in evaluative metering mode then the exposure is set when focus is achieved when you depress the shutter release half way and stays there for the burst.  If you go to a different metering mode, it will meter at the time of exposure instead of staying locked.



EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video

The canon folks tell me that each burst image should be re-metered even in one shot AF mode, and want the camera to be sent in to be fixed.


I found this in the manual:

“AE lock:        Auto: Applied in One-Shot AF mode with evaluative metering when focus is achieved

                      Manual: With AE lock button”


What isn't clear is whether the AE lock is supposed to remain when shooting bursts. Came across this situation while burst shooting a bunch of stationary flaming matches. Usually shoot bursts in AI servo for moving subjects, but used one shot because AF didn't need to change.


Now I'm not sure if this is a problem or a feature...

Take a look at the footnote on the bottom of P. 239 of the manual.  Are you using evaluative metering mode?


I tried to copy and paste it here but apparently Canon has some protections applied to the PDF version of the manual making copy difficult.




EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video

I do not use One Shot AF with Continuous Drive mode.  If I am using One Shot AF, then I use Single Shot drive mode.  If I am using AI Servo AF, then I always use Continuous Drive mode.  I suggest that you stick with AI Servo mode to achieve what you want.


If you want the camera to lock focus on every frame in Continuous Drive mode, then set Image Priority to full tilt Focus Priority.  This will force the camera to wait until it locks focus before if fires the shutter again, but because you are in AI Servo mode it will also meter for a new exposure on every frame.  This behavior is identical to One Shot AF.


Focus Priority has two settings, 1st Image and 2nd Image.  The 1st Image Priority setting sets the behavior for the first frame in a burst of frame captures.  The 2nd Image Priority setting sets the behavior for all of the subsequent frames after the first frame.





I normally set both 1st and 2nd Image Priority settings to full focus priority.  At the opposite end of the scale is shutter priority, which does not wait for a focus lock.  Using shutter priority yields the fastest frame rates.  But, what is the point of high frame rates when the images are OOF?  I would rather have a burst of frames that are in focus, instead of near focus.


Besides, Canon's super telephoto L lenses can focus so quickly that any hit you might take in your frame rate is well worth the uptick in your keeper rate.  


Some people may want to set the 1st Image Priority to Shutter Priority, which causes the camera to "jump start" itself into Continuous Drive.  I have found this approach to be highly effective when I pre-focus on an area where I know the action will be taking place.  By the time the cameras hits the 2nd Frame, it has locked onto a subject and tracks it.


Of course, if you are using only one AF point, then you will only have focus tracking at the one AF point that you have selected.  If you enable multiple AF points, then the Case Settings become meaningful, and the Image Priority settings take on a greater significance on your final results.

"The right mouse button is your friend."

I just use a screenshot.


If I understand your situation correctly I think it is working normally. 


"when autofocus is changed to One Shot", is doing what it does. If you are in doubt reset it and try again.


EOS 1DX and 1D Mk IV and less lenses then before!

@ebiggs1 wrote:

If I understand your situation correctly I think it is working normally. 


"when autofocus is changed to One Shot", is doing what it does. If you are in doubt reset it and try again.


It is operating "correctly."  The problem is that behavior is not the desired behavior. 


When you are in One Shot Mode, the exposure will stay locked in until you fully release the shutter.  In Continuous Drive Mode, One Shot AF will refocus each shot but not meter each shot.  Metering is locked until you release the Shutter Button.


If you use AI Servo, with Image Priority set to full Focus Priority, then the camera will both refocus and remeter the scene, which is the desired behavior.

"The right mouse button is your friend."

I sort of think the same way. Yet the canon techs tell me otherwise. Recently asked them if they'd actually tried to replicate my issue with a real camera rather than just assuming how it's supposed to function. We'll see...

Usually when on the phone they do.

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