1Dx Mk2 Owners help please?

Hello:

I'm having a problem with my camera (1Dx Mk2)

With the iso set at sub 640 and the firing rate set at 14 fps, the camera sounds as if it is really going at 14 fps. I have no method of measuring this accurately.

If, using the Q menu, I change the iso to 25600, the fps rate drops to (at a guess) 8 fps.

Is this normal?
Could someone else try this and see if they get the same result?

It makes no difference using either the cf or the cfast card.
I am shooting in raw and not using ANY in camera image adjustments.

My thanks in advance.

I can't duplicate it. If you can provide more settings, I'll try to match what you're doing.

LJ3Jim wrote in post #18400446
I can't duplicate it. If you can provide more settings, I'll try to match what you're doing.

I'll get back to you with the settings.

Can you tell me which firmware version you are on?

1.1.3

LJ3Jim wrote in post #18400832
1.1.3

Same as mine.

I have turned off all in camera image adjustments including flicker detection.
I am shooting with a 100-400 mk2 at 100 mm wide open. IS mode 1.
Case 1 AF not modified.
AI servo.
Continuous high speed shooting.
I'm saving to a Lexar 64gb Cfast card 3500X.
Battery is showing 60% charge.
I'm changing the iso via the Q menu.

I read something about the frame rate dropping to 10 fps at 3200 and above on the canon uk faqs but the conditions were ambiguous.

I think I may have a dud camera.

john crossley wrote in post #18400888

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I read that bit too but it's nice and warm in the south at the moment.
I would have guessed at battery charge but others suggest not.

I'm using the camera outside in sunny conditions.
I see the same thing with my 85 1.2 and 24-105.

I was originally testing high iso noise levels when I discovered this on my copy.

What I do to make this happen is:

Take a 1 (ish) second burst at say iso 640.
Using the Q menu, change the iso to 25600.
Take another 1 second burst.

The frame rate drops to, what sounds like 8-10 fps.


I guess I shouldn't worry too much as I rarely shoot at over iso 640. It's just a bit annoying.

Tried a few more times. I did notice a slowdown in "HI" iso mode. I didn't notice a slowdown in any other scenario.

If you are jumping from ISO 640 to ISO 25600, and you were already at 1/1000, to meet the requirements in the manual for 14 fps, then it would be impossible for you to have remained at maximum aperture, since you are adding over five stops of ISO. At 1/1000 you only have three stops of shutter speed left.

Alan

BigAl007 wrote in post #18403603
If you are jumping from ISO 640 to ISO 25600, and you were already at 1/1000, to meet the requirements in the manual for 14 fps, then it would be impossible for you to have remained at maximum aperture, since you are adding over five stops of ISO. At 1/1000 you only have three stops of shutter speed left.

Alan

That is true.
I failed to mention I was using AV safety shift.

fordmondeo wrote in post #18403787
That is true.
I failed to mention I was using AV safety shift.

If you are using Av with safety shift enabled, and a fixed ISO, and you started out at 1/1000s and added five stops of ISO the camera will have no alternative but to stop down will it? If you really want to know how fast the camera is shooting just video a burst with your phone, and count the number of exposures that happen in 30 frames, while stepping through them a frame at a time. At least that way you will know exactly what your camera is capable of.

Alan

Would High ISO noise reduction be turned on by any chance....

BigAl007 wrote in post #18403812
If you are using Av with safety shift enabled, and a fixed ISO, and you started out at 1/1000s and added five stops of ISO the camera will have no alternative but to stop down will it? If you really want to know how fast the camera is shooting just video a burst with your phone, and count the number of exposures that happen in 30 frames, while stepping through them a frame at a time. At least that way you will know exactly what your camera is capable of.

Alan

True again.
I needed to keep the shutter speed as high as possible.

graham121 wrote in post #18403846
Would High ISO noise reduction be turned on by any chance....

I disabled everything in the way of in camera processing.
As someone pointed out earlier, canon do say the shutter speed will be reduced at high iso levels.