Camera Viewfinder Light Leak Tests

[Mike]

Purely out of interest I was curious just how much light might make it onto the sensors on my Nikon and Canon through the viewfinders when left uncovered. So I took both cameras and did a 10 minute exposure with the lens cap on, but with a bright light shining into the viewfinder. The results were very interesting and certainly show it pays to cover the viewfinder up with long exposures.

CANON 1000D (Modded)

Nikon D7000

[JonH]

That's something I hadn't even thought about, the Nikon especially seems to have a lot of light getting threw!

[Mike]

Yeah. It does come with a little cover you can slide over the viewfinder for just this purpose. But if you forget to do it then there is always the possibility of extraneous light getting onto your frames that would be difficult to process out.

[MarkS]

The results were very interesting and certainly show it pays to cover the viewfinder up with long exposures.

Interesting - certainly something to be taken into consideration when shooting darks during daylight hours.

[JonH]

Well its not like i ever use the viewfinder so might have to attack it with some black tape now, I don't much like the idea of all that stray light possibly getting in.

[Mike]

This is a pretty extreme demonstration. There was a very bright light put near the viewfinder. Out in the field you will be in a pretty dark environment so bright lights shouldn't get in. But if you use a headtorch or other lights on the opposite site of your scope thinking its harmless, then this is something to think about. Also lights on laptops and other equipment could leak into the camera.