Light leaking back through VF

[HH3]

I used to own a Beaulieu R16 and it had a rotating mirror shutter VF, so when the shutter was open the VF was closed (a flicker effect in VF). This assured that no light could come through the VF and expose the film.

Will my Nizo 4080 VF (beam splitter) have to be covered when not putting my eye up to the VF, or will it only be effected if there is direct light shinning back through the VF (like bright sunlight)? Anyone have any problems with this in Super 8 or should I not worry about it? My previous film experience was all in 16mm using Beaulieu's or Arri's, so I never had this problem.

[rollemfilm]

on some super8 cameras you either have a diopter shutter or you get a small cap with the camera. i would cover it myself if i was you, just to be safe.

[AlexGfromUK]

I have a braun nizo 801 macro, and in the instructions it says that the the camera is specially designed so that no light entering the viewfinder can reach the film. My camera is pretty near the top of the range for silent, and yours is for sound, so I think the optical design features will be similar.
In other words I think your camera will be safe from these types of light leaks, though these are possible with some s8 cameras.

I never covered the viewfinder when taking my eye away from it, and the output I have had back from the camera is of phenominal quality (I guess its that beautiful lens), with no indications of any light leaks.

[tom hardwick]

My 1014E has a little sliding switch up near the v/f eyepiece and it's there for a very good reason, as I found out.

I was filming a group of people out in the sunshine. I was tracking around them and at one point I raised the camera from my eye and held it up high at arm's length as I tracked.

The resulting film shows quite clearly the effect of sunlight entering the v/f optics and impregnating the film via the beam splitting prism; the flare spot is very large and noticeable.

I know this is v/f flare and not lens flare by the way, as I got the latter when I was 180 degrees further round the same group.

So unless your cam has a mirror shutter (as the Beaulieu) then you're getting image dilution if that eyepiece is left uncovered, it's as simple as that. It may not be very noticeable on your 801 Alex, but it sure is there and easy to test for.

tom.

[AlexGfromUK]

I'm sure it does'nt because a) the image quality is extremely good with no signs of flares that don't come from the lens, and no signs of fogging and b) heres a quote from the instructions

"it (the rubber eye cup) helps to prevent extraneous light from affecting the quality of the view finder image. However, no light can in any circumstances reach the film after penetrating the viewfinder"

Thats what the instructions say, I know other cameras have to have the viewfinder covered though. I'm happy with the results I've had.

[ekoe]

just a minor point of contention, the original poster stated:
'My previous film experience was all in 16mm using Beaulieu's or Arri's, so I never had this problem.'
this seems to suggest that flashing originating through the viewfinder does not occur in 16mm, it does. maybe not with beaulieu's mirror shutter, as is the case with the super8mm beaulieu, but certainly with the arri s and arri sr2.

[HH3]

How can the Arri S have a flash problem through the VF when it has a rotating mirror shutter like the Beaulieu R16? If you look through the VF of the Arri S and turn the little knob at the end of the motor you'll see the VF open and close as the mirror is rotating in and out of view. I don't see how this can happen.

[AlexGfromUK]

I agree with ekoe, I've never used a 16mm camera, but from what I've read in kris malkiewicz's "cinematography" the effect is quite severe. any light path that works "forwards" has to work "backwards" does'nt it?. I thought the point of a mirror shutter was really to make the most of the light entering the camera by passing 100% of it to the viewfinder then the film alternately, rather than portioning it up like a beam splitter and sacrificing the intensity of both.

[Alex]

Tom, in low-light scenario's, would keeping the viewfinder exposed be a primitive way of "flashing" the film?

-Alex

[tom hardwick]

Interesting thought Alex that light entering the v/f could gently fog the film and therefore "flash" it as you'd do to reduce contrast when copying slides say.

But my experience is that the fogging isn't uniform and is therefore only detremental, not helpful.

But now to AlexG - are you reading from the 1014E's instructions? If so I don't remember reading that in my book (I'll check later) and in fact I think quite the opposite is the case. Canon fitted that snappy v/f shutter for just this reason: that film fogging through the v/f via the beam splitting prism in the optical path is indeed a distinct possibility.

As you say, beam splitters don't know up from down. They'll happily let light travel both ways, so in good light you can actually film with the 1014 using the v/f as a lens. Don't waste much film on this experiment though; I doubt if the footage will be sharp or well exposed.

But look down into that lens in a dark room with the v/f pointing out into the light. What do you see? An image, that's what. So use that v/f shutter folks.

tom.