Canon EOS 5D Mark IV - Burst brightness problem

[oldschooltz]

Good evening,

I have a Canon EOS 5D Mark IV for about a year now. Lately, I have a problem when shooting in burst. I always use the settings on 'Manual' and the RAW format, but there is a big brightness difference between the photos. On some, there is a huge difference between different parts of the photo, half is very well lit and the other is the opposite.

I don't know what the problem could be, if maybe there is a setting or a more serious issue.

Any ideas? Thank you in advance

[kvbarkley]

Sounds like a failing shutter. Can you provide an example.

[Nick2020]

Hi oldschooltz,

Thanks for checking in with us!

To help us get a better sense of what you're facing, can you elaborate on what shooting settings and metering mode you're using?

[oldschooltz]

Hello,

The camera was on Manual, Exposure time 1/256 sec, Exposure Bias on 0 EV, F number 1.41, Iso 4000, focal length 35 mm, Metering Mode spot.

The setting are the same for all pictures, of course.

[wq9nsc]

What was the lighting source?  LED and CFL lights flicker in time with the 60 hz line frequency and because your camera shutter isn't synced to the line frequency the lighting level will vary depending upon where the illumination is cycling as your shutter cycles.  Older style incandescent filaments have sufficient thermal lag that this isn't apparent.

Many of the newer light styles will show a distinct change in color temperature across the operating cycle of the lamp and some LED devices are particular bad.

Rodger

[Waddizzle]

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@oldschooltz wrote:

Hello,

The camera was on Manual, Exposure time 1/256 sec, Exposure Bias on 0 EV, F number 1.41, Iso 4000, focal length 35 mm, Metering Mode spot.

The setting are the same for all pictures, of course.

---

Shooting handheld with Spot Metering can be a little tricky.  With the exception of the 1D series, Spot Metering will always take place under the center AF point.  If you are only using the center AF point for focusing, then metering only at the center should not be an issue.

I suggest that you use the default Evaluative Metering or Center Weighted Metering modes.  Also, it has already been pointed out that flicker from solid state and flourescent lights can cause your issue.  You will want to enable the Light Flicker setting your camera.

[oldschooltz]

Hello again,

Thanks for the advice. Unfortunately none of the solutions offered are working.

I have turned on the flickering compensation, no change. The metering mode has no effect on manual settings...

But I have discovered that un normal burst mode, not high speed burst mode, the problem disappears. I am thinking that it's probably a shutter issue...

[Waddizzle]

I used to get the outlier under/over exposure from time to time.  I could never explain it, except that I changed to using BBF, and the problem went away.  My guess is that my thumb hand nothing to do, except to hang out on the rear panel, would hit AE Lock once in a while as I was walking around.

[Waddizzle]

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@oldschooltz wrote:

Hello again,

Thanks for the advice. Unfortunately none of the solutions offered are working.

I have turned on the flickering compensation, no change. The metering mode has no effect on manual settings...

But I have discovered that un normal burst mode, not high speed burst mode, the problem disappears. I am thinking that it's probably a shutter issue...

---

Does that mean you tried switching out of Spot Metering mode, and it made no difference?  Yes, you are correct.  Metering mode has no effect on manual settings.  It is not supposed to have a direct affect on exposure settings in Manual mode.  

As I look at your sample photos, center AF point could be out in the hallway somewhere.  I you were using Spot Metering, then it is possible that metering was measured in the hallway.  

You can use Canon's DPP application to see where the center AF point is located in each shot.  This is just a possibility of where the photo was metered.  If you focused and recomposes the shot, it could be anywhere.

[wq9nsc]

It could be a shutter issue but a lot of current LED bulbs use a very simple type switching power converter in the base of the bulb and those are not perfectly synchronized to the line frequency.  The algorithm in the Canon cameras will try to sync exactly to either 50 or 60 hertz so the pseudo random flicker of these types of bulbs will still produce flicker. And although the line frequency should be very stable on the grid, noise from all of the cheaply made switch mode power supplies in pretty much all consumer products now creates line "garbage" and transients which cause additional random flicker from LED bulbs.  The old tungsten filament bulbs are very nice for photography because the filament doesn't cool/heat quickly enough to create flicker measured with anything with a slower response than a fast risetime scope.

The Canon algorithm works perfectly for high intensity discharge lamps like the sodium and mercury vapor bulbs found in stadiums which are driven directly off the line via a ballast and flicker in perfect sync with the line but newer high efficiency bulbs are going to be a problem that at this point can only be addressed in post.

Rodger