topic Re: Problems with exposure in EOS DSLR & Mirrorless Cameras

Problems with exposure

TurtleDownUnder — Sat, 03 Nov 2018 23:37:08 GMT

I have recently bought a new Canon 5D mark IV and am having problems with exposure. I am using an older EF 24-105 lens. I have experimented with different metering modes and still seem to have the problem. Two photos taken back-to-back with exactly the same settings and the same field of view have dramatically different exposures. One will be just fine, the next completely blown out. See an example below:

ISO 320 1/400 sec f/14

Any ideas, suggestions. Am I doing something wrong or is there a problem with the camera and/or lens?

Re: Problems with exposure

Waddizzle — Sun, 04 Nov 2018 00:00:43 GMT

Are you using One Shot mode? For this type of shot, I would use One Shot AF mode, and Single Shot drive mode.

What metering mode are you using? I find that Evaluative Metering works just fine for 99.99% of my handheld shots. Sometimes trying to keep the metering system alive, you can inadvertently lock exposure. One day I noticed that I had locked exposure after reviewing shots on the LCD.

What shooting mode are you using? You should be able to see the bad exposures in the viewfinder display.

Re: Problems with exposure

Waddizzle — Sun, 04 Nov 2018 00:06:36 GMT

BTW, I think the first shot is under exposed. The second shot is obviously overexposed. Make sure the camera is not trying to capture a set of HDR exposures. You can either find the setting in the menus, or reset the camera back to factory defaults.

I think shooting at f/14 is unnecessary when shooting with a wide angle focal length. With a focal length of 24mm, an aperture of f/8 should be sufficient. This will allow you to raise the shutter speed. I would want to use at least 1/1000 for these shots.

Re: Problems with exposure

Peter — Sun, 04 Nov 2018 09:58:27 GMT

My two thoughts:

1. stuck aperture

2. wrong EXIF

The first image has readable EXIF, the second one not. The second one is also a small image so it is hard to see any change in DOF.

BTW, your firmware is 1.0.4. Latest is 1.1.2.

Re: Problems with exposure

Ray-uk — Sun, 04 Nov 2018 11:20:18 GMT

The 24-105 Mk 1 is prone to having a broken internal cable which can give intermittent focusing and/or aperture control. To check this put the camera into M mode, look into the front of the lens, hold the DOF button in and change the aperture through all values, you should be able to see it change at each step. Try this at different zoom levels.

Re: Problems with exposure

Waddizzle — Sun, 04 Nov 2018 14:12:50 GMT

@Ray-uk wrote:
The 24-105 Mk 1 is prone to having a broken internal cable which can give intermittent focusing and/or aperture control. To check this put the camera into M mode, look into the front of the lens, hold the DOF button in and change the aperture through all values, you should be able to see it change at each step. Try this at different zoom levels.

I am not totally convinced that the OP is using the EF 24-105mm f/4L IS USM.

That is good advice on how to test an automatic aperture. It helps to use a tripod, or look into a mirror when you do it.

Re: Problems with exposure

ebiggs1 — Sun, 04 Nov 2018 15:25:38 GMT

"Any ideas, suggestions."

Yes, your lens did not stop down. Simple. Are you using high speed shooting mode?

Wait, wait, did I hear somebody say "light flicker"?

Re: Problems with exposure

Waddizzle — Sun, 04 Nov 2018 15:40:33 GMT

@ebiggs1 wrote:
"Any ideas, suggestions."

Yes, your lens did not stop down. Simple. Are you using high speed shooting mode?

Wait, wait, did I hear somebody say "light flicker"?

No, you did not. You’re hearing voices in your head again.

Re: Problems with exposure

TurtleDownUnder — Mon, 05 Nov 2018 06:22:56 GMT

I was using M - manual shooting mode for these shots and high speed continuous shooting. But it doesn't matter. I have the same problems on P (program) and without continuous shooting. One shot will look fine and then the next shot (same settings, same subject matter) is completely over exposed. Really frustrating!

Re: Problems with exposure

ebiggs1 — Mon, 05 Nov 2018 13:58:29 GMT

"One shot will look fine and then the next shot (same settings, same subject matter) is completely over exposed."

How often does this happen? Once in a long while, I will say nothing is wrong. Otherwise you may want to have Canon look at it.

Re: Problems with exposure

Peter — Mon, 05 Nov 2018 16:53:01 GMT

Then it sounds like a stuck aperture. Some 24-105/4L IS have issues with a cable, as written before.

Re: Problems with exposure

ebiggs1 — Mon, 05 Nov 2018 19:09:17 GMT

"...it sounds like a stuck aperture."

The aperture can't be stuck. It might be sticking but since it works some or most of the time it can't be stuck.

Re: Problems with exposure

TurtleDownUnder — Tue, 06 Nov 2018 09:48:12 GMT

Unfortunately, it is happening quite regularly. Sadly, I live on a remote island in the far north of Australia, so getting Canon to have a look at it isn't that easy.

Re: Problems with exposure

ebiggs1 — Tue, 06 Nov 2018 14:15:42 GMT

Easy or not, your solutions are service or new.