Strange film lighting

[Tru-la-la]

Hi all!
A have a problem with my Leica M6. Sometimes I see strange film fogging (see the attachment). It can happend for example on 2 consecutive frames in the middle of the film while all frames before and after are ok. I don't think that it can be from cassette because the fogging is alway of the same shape, it just changes its horisontal position on the frame. However the vertical position is almost constant. It is somewhere on 1/3 of the frame size from the bottom.
I can't reproduce situations when it happes, but it seem to be when the outside light is strong (sunny day). I tried to light up the camera from outside and see any light going into the chamber of the camera. But the result was neagtive.
Do you have any sujestions what it can be?

 

[Ben Z]

Just a guess: tiny pinhole in the first shutter curtain. Enough to fog the film in a diffused circle when exposed to light for a time, but too small to make streaks when the curtain is moving. Actually in your shot it looks more like a reflection of some kind (flare) but your description rules that out.

 

[telenous]

You may also wish to check this thread

http://www.rangefinderforum.com/forums/showthread.php?t=17538&highlight=telenous

about a problem with a lens that bedevilled me for a little while (caused sometimes a white dot area in the middle of the photos)

However the first cause for concern must be the pinhole Ben mentioned just above.

 

[Tru-la-la]

Thanks for responds.
2Ben Z: for me it also looks like a flare, I just cant get from what. But if it is a pinhole in the first curtain it can be tested easily: I just open the objective and put camera without rewinding under the lamp. If the pinhole is there it should be exposed on the film. Right? I usualy always rewind film, but maybe I just forgoten to do it those times.

 

[Tru-la-la]

I just rechecked the first curtain and couldn't see any hole with my eyes. Let's see what a film will tell us.

 

[Nick R.]

I'm suspicious of flare too, as Alkis says, because of the placement of the strong light source almost directly above the light patch. Do the other shots that display this phenomena have a similar light source in the frame?

 

[egpj]

Looks like flare.

 

[Finder]

Do you have a filter on the lens? Is it multicoated? I have just had a similar problem with a center filter on a panoramic camera, but it was caused by air bubbles in the glass - not that your problem is an air bubble problem, but perhaps the filter is inducing the flare from reflections from the front element. Just a thought.



Either that, or you should stay away from cheap German optics. ;->

 

[Tru-la-la]

2Nick R.: No. I put one more pic in attachment. It was taken in cloudy day under trees, so there were no any strong light sources.

2Finder: These two pictures were taken without filters and even with different objectives. The first one with Summilux 35/1.4 the second one with Summicron 50/2. So I tend to think that the flare (if it is) comes from the camera.

 

[Tru-la-la]

I made the test today. I held the camera under a lamp for some time without film rewinding. Didn't get any foging. Wired.

 

[merciful]

I'm not one for diagnosing problems, but I'm very impressed with the shot of the nuns. Lovely dark colours.

 

[jaapv]

A ghost?? Paranormal photography?

 

[jlw]

You may be getting a reflection off some shiny object in the camera interior, such as the rangefinder coupling roller or the back of the chrome camera mounting flange. Notice that it is always about the same shape and always appears more or less opposite of a bright light in the picture area (the lamp in picture 1, the patch of bright sky in picture 2.)

When trying to spot what might be causing the reflection, remember that the image is formed in the camera upside-down, so the fact that the spot is toward the bottom of the picture means you have to look toward the top of the image plane. Try flipping up the back of the camera, opening the shutter on B, and looking in through the back with the lens pointed toward a strong light, and see if you can spot anything shiny inside the top part of the camera "throat."