Lens flare(?) problem with Bronica GS-1

[Paul Thomas]

Hi Everyone,

I'm working what looks like a lens flare issue that _I think_ is with a specific lens (a PG 110 mm macro) on a Bronica GS-1. The blueness of it and the sensitivity to sun angle makes me think its a lens problem. The fact that it takes the same shape and is in the same location in the pictures where it occurs seems strange to me. I have looked through the lens and cannot see any glass imperfection that would cause it. I don't think it's a light leak further back in the light path, e.g. inside a lens back, because I think that would not be blue in color.

What I've done and am doing: using other lenses to confirm the problem is with this lens only (in process); using other film backs (the flare appears with that lens using different backs); looking closely at the 110 mm lens to look for imperfections (not found anything yet); using lens hoods for all shots (in process; I did not use lens hoods in the attached pictures).

I have taken quite a few rolls with other PG lenses on this camera (50 mm up to 250 mm) and not seen this lens flare.

Key to pictures: first four taken within twenty minute period. Same film back (Ektar 100), same lens (110 mm macro). No lens flare apparent in #4. Last one taken with different film back (XP2 400) on cloudy/rainy day with same 110 mm lens - lens flare on this one, too.

Any thoughts? I am trying to be systematic on the testing for this. I'd be especially interested if anyone has seen any lens flare that looks like this before.

--Paul Thomas

 

[gone]

The only time I've seen anything like you're getting was on a 35mm screw mount camera that had a tear in it's shutter. Your last shot appears to have been taken in shade, and I can't imagine a lens flare in that situation.....but there's always a first time. Still, seems unlikely.

Is it possible that the lens isn't seating all the way on the mount? Or that it has a light leak itself?

 

[cramej]

Light leak, not lens flare. Consider that all the images with the leak have the light from beside or behind the camera and nowhere near in the frame. That doesn't mean the leak can't come from the lens, though.

 

[Sirius Glass]

If it is a light leak on the bottom left of the photograph, look for the leak at the top right of the camera. Remember that the lens reverses the image.

 

[Paul Thomas]

Hi Everyone:

I found it, I think! Missing screw at the back of the reflex mirror. Upper right hand side, so the light leaking through from the finder would appear on the lower left of the negative, and would vary in brightness according to lighting conditions on the side of the camera.

I was on the wrong track concentrating on the lens.

Thank you so much for your suggestions!

—Paul Thomas

 

[Sirius Glass]

Great! You got your investment back from what you paid into Photrio!

 

[ic-racer]

Good find!