topic Re: Intermittent over exposure in EOS DSLR & Mirrorless Cameras

Intermittent over exposure

Markgibson3027 — Fri, 24 Aug 2018 17:35:21 GMT

1dx

When using my x2 teleconvertor and 300mm f2.8 mkii I occasionally get over exposure issues. I shoot in manual with auto iso 50% of the time it exposes perfectly. I then get loads of images totally over exposed. Tried all different metering types. Sometimes the over exposure is almost 2 stops. Sometimes by removing the lens and refitting helps. Any solutions please because this is now causing me many hours of grief and 100's of lost pictures.

Re: Intermittent over exposure

Ray-uk — Fri, 24 Aug 2018 19:16:07 GMT

You may have a fault with the diaphragm in the lens (the mechanical bit that gives you the different apertures).

To test this put the camera in M or AV mode, set the lens to the smallest aperture, look into the end of the lens and press the DOF preview button on the camera. Do this repeatedly and you should see the aperture close to the same size opening each time, repeat the procedure for other apertures. Try the same thing with and without the teleconverter.

Re: Intermittent over exposure

Markgibson3027 — Fri, 24 Aug 2018 19:41:06 GMT

Tried that. 50 presses with and 50 presses without the convertor and the aperture opened on each and every press. Although around 3 times there was a slight delay.

Re: Intermittent over exposure

kvbarkley — Fri, 24 Aug 2018 21:25:25 GMT

Have you tried manual ISO with Manual exposure?

Re: Intermittent over exposure

Waddizzle — Fri, 24 Aug 2018 23:34:22 GMT

@Markgibson3027 wrote:
1dx

When using my x2 teleconvertor and 300mm f2.8 mkii I occasionally get over exposure issues. I shoot in manual with auto iso 50% of the time it exposes perfectly. I then get loads of images totally over exposed. Tried all different metering types. Sometimes the over exposure is almost 2 stops. Sometimes by removing the lens and refitting helps. Any solutions please because this is now causing me many hours of grief and 100's of lost pictures.

I used to have this problem with my T5 and 6D. Note the past tense. I never did figure out what caused [it], but it went away.

The fact that it was happening with two bodies made [me] rule out the bodies, and examine what I could be doing. I noticed that it would only happen when I got into a “flow” of taking photos, so my attention was [elsewhere], on the subject and getting the shot, not on the details of using the camera.

As an experiment, I began using BBF, back button focus on the 6D. Coincidentally, I had also begun using a battery grip. It took about a month before I noticed that the occasional bad exposure seemed to have gone on a sabbatical. This was my only clue. And, the problem seems to have cured itself.

My best guess as to what I was doing wrong was that my thumb was wandering around, and locking focus. I had a habit of keeping the camera “awake”, so that I could take a quick shot. But, taking quick shots did not seem to have any impact on when a bad exposure would show up.

Once i started using BBF, my thumb had something to do, and was no longer locking exposure without me noticing. But, like I said, all of this is guess work and assumptions. All I know for certain is that I changed the way I handled the camera, and the problem went away.

Re: Intermittent over exposure

Markgibson3027 — Sat, 25 Aug 2018 10:16:08 GMT

When it happens it seems to last for over 50 shots in succession. I'll change from auto iso to manual I'll also under expose by up to 2 stops and still it will appear very washed out with it clipping the right on the histogram. Seems to happen more when the sun is in my face. I definitely think it's lens orientated as ive never had these issues with other lenses on the body.

Re: Intermittent over exposure

coachboz68 — Sat, 25 Aug 2018 13:30:31 GMT

@Markgibson3027 wrote:
When it happens it seems to last for over 50 shots in succession. I'll change from auto iso to manual I'll also under expose by up to 2 stops and still it will appear very washed out with it clipping the right on the histogram. Seems to happen more when the sun is in my face. I definitely think it's lens orientated as ive never had these issues with other lenses on the body.

I have the 1DXII and a series of L lenses. I have never had it happen for a long sequence of shots like you describe, but I always have it happen on some shots during a night of shooting sports. I can never figure out why, and generally it's only a few in a long sequence, so I just chalk it up to the fact that I'm panning/zooming while taking high rate bursts so the lighting is changing quite a lot from a sensor perspective, though perhaps not human perspective. I use BBF and tend to take my finger off the shutter button (set to Metering Start) from time to time during a burst. It's never so extreme that I cannot easily adjust the RAW file in post processing, so I don't worry about it too much. But again, I haven't had something like you describe with 50 shots in a row consistently improperly exposed.

Re: Intermittent over exposure

Markgibson3027 — Sat, 25 Aug 2018 13:45:06 GMT

I've received some feedback from the shop I got it from. They say check and clean the connectors between lens and camera. Will give this a try. I found with the amount of over exposure it has also lead to the images being very soft. To the point of unrecoverable.

Re: Intermittent over exposure

Waddizzle — Sat, 25 Aug 2018 14:26:44 GMT

@Markgibson3027 wrote:
I've received some feedback from the shop I got it from. They say check and clean the connectors between lens and camera. Will give this a try. I found with the amount of over exposure it has also lead to the images being very soft. To the point of unrecoverable.

Nonsense. Do not waste your time cleaning the contacts, not unless you can SEE something there.

Do you wear eyeglasses? Did you know that light entering the viewfinder through the eyepiece can affect the measured exposure? I wear eyeglasses and have long suspected this as a reason for a bad exposure.

I suggest looking less at the camera, and look more at what you are doing.

Re: Intermittent over exposure

Markgibson3027 — Sat, 25 Aug 2018 14:46:51 GMT

It just seems strange that images minutes apart can't become greatly over exposed. I've shot my 100-400 on the same body for over 6000 shots with only the occaonal over exposure. Now using the 300 f2.8 and x2 teleconvertor I've shot with around 30% over exposed. I don't think it's the user I think it could be something technical. Although I am new to using a prime lens.

Re: Intermittent over exposure

Waddizzle — Sat, 25 Aug 2018 15:01:43 GMT

@Markgibson3027 wrote:
It just seems strange that images minutes apart can't become greatly over exposed. I've shot my 100-400 on the same body for over 6000 shots with only the occaonal over exposure. Now using the 300 f2.8 and x2 teleconvertor I've shot with around 30% over exposed. I don't think it's the user I think it could be something technical. Although I am new to using a prime lens.

Are you using any sort of filter on the lens? I only use B+W Nano Clear filters on my “L” lenses. Other filter types seem to affect the focusing ability, not the exposures though.

Re: Intermittent over exposure

Markgibson3027 — Sat, 25 Aug 2018 15:06:45 GMT

Not using any filters.

Re: Intermittent over exposure

Waddizzle — Sat, 25 Aug 2018 15:08:03 GMT

@Markgibson3027 wrote:
It just seems strange that images minutes apart can't become greatly over exposed. I've shot my 100-400 on the same body for over 6000 shots with only the occaonal over exposure. Now using the 300 f2.8 and x2 teleconvertor I've shot with around 30% over exposed. I don't think it's the user I think it could be something technical. Although I am new to using a prime lens.

Using the teleconverter can slow everything down. What happens to exposures when you do not use it?

I am guessing that you are using AI Servo focusing mode, and Continuous Shot shooting mode, with that setup. How is your Image Priority set? I have both 1st and 2nd Image Priority set for full tilt Focus Priority, which means that camera waits for a focus lock before it fires the shutter in Continuous Shot mode. This may also have an collateral impact on metering, too.

Re: Intermittent over exposure

Markgibson3027 — Thu, 30 Aug 2018 07:38:22 GMT

I will tey to change this again. When I 1st had the issue i changed the 1st and 2nd shot priority thinking this could be the issue. And it still occurred. This weekend I will try with the 1.4 teleconvertor and see if this has any direct impact.

Re: Intermittent over exposure

Ray-uk — Fri, 31 Aug 2018 10:54:50 GMT

1st & 2nd shot priority is related to autofocus and has nothing to do with exposure.

Re: Intermittent over exposure

ebiggs1 — Fri, 31 Aug 2018 14:40:52 GMT

The areas where this can happen is this, "I shoot in manual with auto iso 50% of the time it exposes perfectly." So stop using auto ISO. If you check the exif it will probably be very high. Out of reason high.

If that checks out a lens communication between the lens your tel-con and camera. Remove the tel-con. Try it again.

If that checks out the mirror can get lazy and remain partly open. Also mirror bounce can cause this. You will need to have Canon service it with a C&C.

Lastly user error.

Re: Intermittent over exposure

Waddizzle — Fri, 31 Aug 2018 23:40:17 GMT

@Ray-uk wrote:
1st & 2nd shot priority is related to autofocus and has nothing to do with exposure.

You are correct. However, if the lens is OOF, then can not metering become somewhat impaired? Changing metering mode from the factory default, Evaluative Metering, can also cause the occasional series of bad exposures. I see little reason to use the other metering modes, not unless you are using a tripod, or have hands of steel.

I used to have the randoml occurring run of bad exposures far too often to my liking I cannot point blame anything specific, but I top suspect is that I was unknowingly locking exposure. Paying more attention to fingers seem to have cured it..