Flare or lens aperture open?

[Meekyman]

Hi Folks,

Probably a bit of a dumb question and would be easier to illustrate but no scanner at the moment.

OK, so I was in a deepish river valley taking photos of backlit trees besides a stream. The sun was not directly in front of me, but overhead, around 45 degrees to me and early am. The water in the stream is clearly reflective. Anyway, I was careful enough at the time to try to avoid flare from the sun above and used my map in its holder to cast a nice shadow over the lens. Checked that the map holder was not in the frame.

I get my photo back and there's a lovely polygon in the centre of the frame! Damn. I was using negative film and tend to work methodically so that the lens opening was closed and would have tested the shutter at least twice so I am sure the lens opening was closed. Could the polygon be flare from the stream reflecting the sun overhead?

Would my map-holder trick have worked if held between camera and ground? Would a polariser have done anything? I used a small rodenstock 135mm f5.6 (49mm filter) fitted with a Lee filter holder and have a 77mm rubber lens hood that screws into the holder....too shallow/too large to be effective?

Well, I have learnt something I hope!

Graham

[Joe Wright]

Does the polygon have picture detail but different contrast / tonality to the surrounding area, if yes certainly sounds like flare. It sounds as though you had any chance of flare direct from the sun sorted by shading the lens with the map, so possibly light bouncing off another surface directly into the lens.
If you're shutter was open when you pulled the darkslide then you would have blown the whole sheet or at least grossly over-exposed depending how long it was before closing the shutter.
A little technique I've adopted when shooting like this, I do a fair bit into the sun, assuming you have clipped corners on your glass is to look through all the corners with the lens stopped down to your chosen aperture (under the dark cloth with shutter open). Flare sometimes exhibits itself as a thin trace of light from the lens towards your focus screen, looks a bit like the tracer gun fire you see in the war movies! You can then fiddle about to see whether you can mask the flare without obscuring the image.

[Meekyman]

Thanks for your reply Joe.

I can only judge from the negative, but definitely appears to have picture detail - just like someone had stamped a shape over the image!

I'll try your tip for the future.

Cheers

Graham

[Cor]

Were you using a filter ? I had this happening a few times with a Cokin filter (70 dark red) and IR film, sun behind me. I think I traced it back to light from behind bouncing on the sticking out parts of the filter, and than bouncing onto the film.

best,

Cor

[Jerry Bodine]

It certainly sounds to me like the polygon (shape of the aperture) is a product of the sun's reflection off the stream, which will also produce flare. Multiple polygons of varying density can also be produced by reflections off different lens elements. A polarizer would have some effect on specular reflection of sunlight, but will have no effect on reflections from metallic objects (filter rings, etc.). If the sun's reflection is from still water, a single bright polygon is likely. But if the water is moving, the polygon is also moving and would likely produce wild "war movie" tracers on film.

My 2 cents.

[Meekyman]

It is indeed a single bright polygon in the centre of the frame, so I guess it's from the stream. Ah well, another lesson learned. Funny thing is that I have taken photos with a similar set-up with my digital camera and never had this problem. Bizarre.

Thanks for your inputs folks.

Graham

[Robert Opheim]

I have had that polygon show up too. I was shooting a building in Kyoto with a old Brooks Veriwide in the 1980's and I didn't have a lens hood on it. In my case I must have been shooting to close an angle toward the sun. Water reflecting as Jerry Bodine said above will cause it as well. What type of lens were you using? older lenses are more subject to flare and "specular reflection". I have a 1930's Hugo Meyer WA that is very sensitive to direct light.