topic Re: Canon EOS 5D Mark IV - Burst brightness problem in EOS DSLR & Mirrorless Cameras

Canon EOS 5D Mark IV - Burst brightness problem

oldschooltz — Fri, 14 Aug 2020 21:00:44 GMT

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

Re: Canon EOS 5D Mark IV - Burst brightness problem

kvbarkley — Fri, 14 Aug 2020 20:31:10 GMT

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

Re: Canon EOS 5D Mark IV - Burst brightness problem

Nick2020 — Sun, 16 Aug 2020 05:07:52 GMT

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?

Re: Canon EOS 5D Mark IV - Burst brightness problem

oldschooltz — Sun, 16 Aug 2020 09:51:17 GMT

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.

Re: Canon EOS 5D Mark IV - Burst brightness problem

wq9nsc — Sun, 16 Aug 2020 11:19:53 GMT

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

Re: Canon EOS 5D Mark IV - Burst brightness problem

Waddizzle — Sun, 16 Aug 2020 11:58:43 GMT

@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.

Re: Canon EOS 5D Mark IV - Burst brightness problem

oldschooltz — Sun, 16 Aug 2020 12:16:20 GMT

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...

Re: Canon EOS 5D Mark IV - Burst brightness problem

Waddizzle — Sun, 16 Aug 2020 13:14:06 GMT

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.

Re: Canon EOS 5D Mark IV - Burst brightness problem

Waddizzle — Sun, 16 Aug 2020 13:23:20 GMT

@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.

Re: Canon EOS 5D Mark IV - Burst brightness problem

wq9nsc — Sun, 16 Aug 2020 14:10:48 GMT

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

Re: Canon EOS 5D Mark IV - Burst brightness problem

oldschooltz — Tue, 25 Aug 2020 19:07:15 GMT

I tried to see if it happens outside, and it does not. Also, apparently High Burst or Normal Burst does not represent a factor, but the lack of light is a problem. If there is enough light, there is no problem. As soon as the light goes down (inside), then the issue appears.

It might be light flickering, but the camera setting about it does not solve the problem. Is there any other way to resolve it or is there no getting around it?

Re: Canon EOS 5D Mark IV - Burst brightness problem

wq9nsc — Tue, 25 Aug 2020 21:28:25 GMT

Because the flickering of your lighting source is random, the only work around is to change to a different bulb that flickers at the line frequency (or go with old school incandescent lighting) or use an artificial light source that doesn't flicker or flickers at the line rate (pretty much any of the old CFL will flicker at the line rate).

The only way to know for sure which bulb will flicker at the line rate is to test them which is expensive and impractical although you could try with different bulbs you already own and if you find one then try more of that brand HOWEVER the manufacturers are constantly revising these bulbs so that is no guarantee that a new bulb will be like the one you currently own. Cheaper bulbs are more likely to use a simpler largely passive voltage reduction/current limiting network which WILL have a flicker rate synced to the line frequency while dimmable bulbs are more likely to use a higher efficiency switching type source that will flicker randomly.

The in camera flicker reject senses a triggering flicker and then it expects the ensuing flicker to occur at a base rate of 50 or 60 hertz (cycles per second) based upon the power grid in the country and it will modify shutter triggering to avoid triggering when flicker is problematic, that is why the frame rate will slow when anti-flicker is operational. Because the flicker of your lighting does not have this regular fixed rate there is nothing your Canon (or any other) camera can do to avoid the issue. This issue has become increasingly common with the use of higher efficiency power converters for LED and HID lighting.

It can be somewhat addressed in post by shooting in RAW and adjusting exposure and color temperature however in some cases the change will be uneven across the exposure making near perfect cleanup in post exceedingly tedious. Because I primarily shoot sports where timing is critical, I don't use anti-flicker and it is VERY rarely an issue for the type of shooting that I do. In your case it sounds like you need to use a sequence of frames instead of capturing a single frame from an action sequence so you will need to do something to address flicker pre-capture for best results and that involves either changing bulbs or using artificial lighting.

If you see a youtube video of a modern car with LED tail lights, you will see them flickering because the LEDs are driven by a PWM (pulse width modulation) controller driven from DC that controls pulse frequency and duration to provide the desired brightness without damage to the individual LED emitters. Many of the current screw in household bulbs use this same system with a PWM controller that converts the AC input to DC which the PWM controller then uses to achieve the desired perceived brightness by varying the duty cycle of the power to the LED elements. It is typical in these cases to over drive the LED during the on time with a low enough duty cycle not to damage the element by providing sufficient cooling time between high power pulses. PWM controllers are extremely power efficient because they are either on or off with very little resistive loss making them more "green" but they are also the reason that some people are bothered by screw in LED bulbs because although the flicker rate is too fast to be noticeable as flicker, your eyes and brain can respond to a flicker rate that is too high to be consciously noticed. Simple LED light sources like simple flashlights don't have this flicker because the LED is driven by pure, steady direct current that is limited via the power source to a level that is safe for the LED to be driven at continuously. More sophisticated devices pulse the the drive to the LED(s).

Rodger

Re: Canon EOS 5D Mark IV - Burst brightness problem

Hunterphoto — Mon, 31 Aug 2020 12:36:21 GMT

The setting controls are sometimes to difficult to ascertain and use properly, atleast for me. .

I thought I had mine set on ISO 100, a setting that i thought that only I could change, and was not auto, but I was getting over exposed blow outs on occaision, almost at random

When I started comparing the metadata, the ISO was jumping up to 400 or higher, then back to 100 or 200.

Turns out that I had one [that appeared incorrectly unrelated to me] setting clicked on that was causing the ISO to jump up to 400 or higher, then back to 100 or 200, discovered when I started comparing the metadata.

The instruction manual has some details buried somewhere in obscurity within its 600 pages that i used to change to stop the problem that invovled exposure, apperture, time, and ISO

Sorry, i am where i do not have acess to manual, but please look in there first on iso exposures and iso settings, plus auto adjustment settings, but it is hard to find.

Very difficult and hard to find and properly fix or so it was for me, and completely counterintuitive to me.

BTW I could not see the ISO or other settings in your photos.

Just my suggestion.

Re: Canon EOS 5D Mark IV - Burst brightness problem

wq9nsc — Mon, 31 Aug 2020 13:09:47 GMT

Hunterphoto,

Those are the "safety shift" settings which allow the camera to make a setting on its own if the selected setting will result in signficant over or under exposure. I keep those turned off in all of my camera bodies. They are useful in certain situations but not when you want to exercise full control over exposure.

Rodger

Re: Canon EOS 5D Mark IV - Burst brightness problem

Waddizzle — Mon, 31 Aug 2020 14:59:57 GMT

Hunterphoto,

I think light flicker is a likely contributing factor to your issue. But, i would like to see whether or not using Spot Metering is an issue, too. The camera spot meters only at the center AF point, no matter which AF point has been selected.

You can use Canon's DPP4 software to check what part of the scene the center AF point is covering, because that is where the camera will look when it is spot metering to set your ISO. As you say, your ISO seemingly has a mind of its' own. It could be the effects of spot metering.

BTW, I almost never use spot metering handheld. I only use it on a tripod, if then. I get better results with center weighted average metering mode compared to spot metering, which is a little too narrowly measured for most of my scenarios.