Light leaking back through VF

[ekoe]

i stated 'maybe not with beaulieu's mirror shutter' in reference to tom hardwick's statement, but i don't see how a guillotine mirror shutter would prevent this. although it strikes me odd that beaulieu did not equip it's guillotine shutter cameras with viewfinder cut-offs. anyone?
with the rotating mirror shutter on the arri s, when the shutter is open, and the mirror out of place, light entering through the viewfinder can reach the film. this is why the eyepiece is equipped with a hinged metal cap.

[AlexGfromUK]

Tom,

I have a Braun nizo 801 macro not a canon camera at all, maybe thats why we have been confused by each other's messages, our cameras don't have anything in common apart from being old competitors! Since my nizo claims not to let in any light through the open viewfinder, I'll try out your idea of looking through the lens in a dark room out of interest.

[souper8]

Tom,
What does the prism have anything to do with the light coming through the the VF onto the film plane? I have 3 Nizos and none of my Nizos have VF shutters. Isn't the prism is pointed towards the front of the camera and the image split half to the film plane and half towards the VF. The Nizos should not have any problem with light leakage from the VF. I have never had any problems shooting outdoors in bright sun light. I guess it affects only certain cameras.
Cheers

[tom hardwick]

When XL cameras started appearing in the late 70s camera v/f design started to favour the "peek in mirror" idea, where a tiny periscope dipped into the optical path and scooped up a tiny amount of light for the v/f and the meter. You can check to see if your camera has one of these (the Canon 310 and the Eumig Nautica do) by zooming to full telephoto and looking down the lens.

Very often this little mirror was off centre with the optical axis and was therefore less accurate than the on centre beam splitter, but at the same time it was less affected by extraneous light.

Cameras were often fitted with v/f shutters to keep the automatic exposure correct, too. If light hit the Cds cell from the lens and the v/f scenes could be under exposed. OK in manual exposure of course, and we all shoot in manual, don't we?

tom.