Covering eyepiece for long exposures

[dennybeall]

Like so many things this is camera body specific.

 

[KmH]

Don't Believe Everything You Think: The 6 Basic Mistakes We Make in Thinking

I thought about buying that book.
But I didn't because I didn't think I needed it.
Did I make a mistake ?

 

[TCampbell]

I think this depends on the camera. A while back I read an article where they put this to the test.

As I recall the test, they covered the entire camera (lens and viewfinder) and took a long exposure to ensure that the frame was "black" (with maybe some sensor noise). They repeated with only the viewfinder open and a bright light shining into it.

It turns out, on the camera they tested, there was no difference noticed between the viewfinder port covered vs. uncovered.

While the test camera seemed to seal off any light leaks rather well, clearly (and historically) it has always been very important -- and probably still is important on many models, just not on every model.

 

[john.margetts]

According to the manual of my Canon DSLR, the reason for covering the eyepiece is to stop light coming in through that route from upsetting the light meter, rather than fogging the image.