I still don't get how the middle portion has any image coming onto it, because it is completely blacked out the whole time even when spinning because the center is solid, is this a factor of light bending?
I still don't get how the middle portion has any image coming onto it, because it is completely blacked out the whole time even when spinning because the center is solid, is this a factor of light bending?
It required a double exposure... An image was shot without the "fan", and another with the spinning "fan" to "burn in" the falloff area...Originally Posted by StoneNYC
Steve K
A lens can't 'see' an object smaller than the aperture diameter when held directly in front of the lens. For example a pencil, finger or fan axle. Try it, put a pencil in front of the lens. The pencil does not block the image until the aperture is stopped down a diameter equal to the width of the pencil. Try it. When the aperture is wider than the width of the pencil the lens 'sees through' the pencil.
The center of the lens was not completely covered. The fan blades were tapered so that more light passed the edge than the center, but there was always light. I had an opportunity to try one many years ago before they got so expensive, but had no real need for a 120 lens on 8x10. Only one exposure was required, not two. The image produced was absolutely rectilinear with no distortion.
Thanks Jim
I've always wanted to try one of the earlier Hypergon lenses, a few years ago they were more common on Ebay but you rarely see them for sale now.
Ian
btw, there are three currently available on the auction site
andrew
There are some example photos hidden away in the archives here. I believe Mark Sawyer had one and showed some examples from 8x10...it was the 90mm variant IIRC.
Cool lens, I would use it if I found one for a few dollars!
The Rodenstock Heligon 130mm covers 8x10 nicely. Rectilinear image with little distortion (or movements) Uncoated, no helicopter blades to get deal with.
LJS
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