Landscape and Viewfinder Light

[snerd]

So, do you slip on the little rubber square to block light from entering through the viewfinder? Is it a problem with all cameras, or just some?

 

[KmH]

Only if I don't have my eye at the viewfinder.
Yes, it affects all SLR and DSLR cameras.
When the main mirror is up during an exposure it does not make a light tight seal against the focusing screen at the top/front of the mirror box.

 

[snerd]

When I shoot landscapes, I mostly use mirror lock-up and a remote shutter cable. No way I'm going to stick my eye into the viewfinder and cause any shake. So I've maybe just discovered part of the problem with my landscape photography! Thanks!

 

[480sparky38 37]

So, do you slip on the little rubber square to block light from entering through the viewfinder? Is it a problem with all cameras, or just some?

Depends on the shutter speed I'm using and what's behind the camera. If I think it's going to be an issue, I just hold my hand near the VF.

 

[justingrainge]

Mirror lock-up takes care of it, I find it a pain to put the strap rubber bit on and off.

 

[Alexr25]

As far as I'm aware the sole purpose of the cover is to prevent stray light from coming through the viewfinder and upsetting the exposure metering. During the actual exposure the mirror stops any stray light from affecting the image.
Most of the time if I'm shooting indoors or outside in the shade I don't bother with the cover but if I'm shooting with the camera in bright sun I either put on the cover or switch to manual exposure.

 

[Forkie]

My camera has a little curtain you can open and close for when doing just these types of images.

 

[tirediron]

I would only worry about this if I were doing longer exposures; >1 second stuff. For every day shooting, I've never noticed an issue.

 

[480sparky38 37]

Mirror lock-up takes care of it............

Um,.... not always.

 

[TCampbell]

I saw a test where the photographer was trying to determine if it was possible for light entering the back of the camera to leak into the photo. To test it, he left the lens cap on and covered every part of the camera EXCEPT the viewfinder. He placed a bright light shining directly into the viewfinder to guarantee LOTS of stray light. He took long exposure images (so the light would have lots of time to leak in) and inspected the results.

If no light leaks, the images should be black (but probably very "noisy"). If there are light leaks, he should see some areas where the image isn't black.

In the end, he was not able to detect any leakage at all. Apparently when the mirror swings up, it does a pretty good job of creating a light-tight seal. I think he tested with a 5D III.

Obviously if you want to know if your camera leaks, you need to test your own camera to be sure.

Light entering through the back can affect metering... but if you've pre-metered your shot and you're shooting on manual... you don't really care because the camera isn't changing it's exposure based on metering at that point.