Topic: Light leak or lens internal reflection?

[Ezzie]

May I request some help here? I´ve had my fair share of trouble with the Kowa Super 66, but after a bit of tinkering my last but one roll was just fine. However this last roll showed up a new phenomenon. The only change being the lens. A new lens to me (a replacement standard 85mm f2.. As you can see from the pictures there is a uniform light intrusion on the frames. Same shape, same location. It is present on more or less all frames. but mostly so on pictures taken in bright sun light, less so when light is diffused or overcast. The light intrusion is not present outside the frame, no bleeding over the edges whatsoever. Is this a reflection or is it a light leak? Why I ask is that the only thing changed since last roll is the lens.

[Fluminian]

I would say it's light leak.

[02Pilot]

My money's on an internal reflection. The consistency and the curvature, as well as the fact that it doesn't extend beyond the frame, suggest something on the inside of the lens. I've got a Jupiter-12 with a tendency toward a weird flare in any sort of bright light - not exactly the same look, but similarly consistent. Try shooting a roll of color with it; I came to the conclusion that mine was internal when I noticed that the flare was consistently purple (as is the lens coating) on color film.

FWIW, I've done everything that can be done minimize the flare on my lens, but there appears to be some part of one of the elements exposed where it is cemented together, so I can't do anything about it unless I separate the group, and I'm not planning on doing that. Barring that particular issue, look for places where there may be exposed reflective surfaces inside the lens and black them out with a Sharpie or thinned flat black model paint.

[Ezzie]

Thanks folks. Next outing with the camera I will take two lenses, and swap between the two. If it shows up on just the one, I think we will have identified the culprit.