790mm F:5.4 LF & ULF Lens Data
My 790mm F:5.4 Wollaston Meniscus lens will be available in a few days, but until then, here 's a data sheet covering the image circle, bellows draw, and effective apertures at various focusing distances.
Notice that it covers a 1425mm (56") diameter circle at infinity, and well over 1830mm (72") !!! when focused at 3 meters (10'). The folks shooting huge wet plate and paper negative portraits now have a really fast lens for ULF alternative photography.
I've just posted the lens details and pricing in the For Sale section.
Thanks for your interest and patience.
P.S.: Craig: you get hororable mention in the evolution of this lens...
Some photos from the 790mm lens
Today I made two paper negatives so you could see how the lens performs at various f:stops.
One shot was at f:6.7 to illustrate soft glow, the other shot was at f:22 to illustrate a soft/sharp rendition.
These are scans of the paper negatives, (no post-scan sharpening was done to either photo.).
Yep, 8x20 Canham, here are some details...
The lens was pre-mounted on a 8.5" square board and clamped to the front posts of my KB Canham 8x20" camera. The Gazebo was 75' (23 meters) away in late morning sunlight. Focusing wide open was very fast on the sunlit vertical fence, no re-focusing was done for each aperture card. I let the inherent depth of focus for this lens express itself at each aperture without tweaking it each time. (I felt it was "right on" at each f:stop).
The Paper Negatives are on 8x20" PhotoWarehouse VC RC paper, (pre flashed 3 seconds @f:32)
Exposures were ▒1.5 seconds @ f:6.7, and 6 seconds @ f:22 (using a cardboard version of Ansel's hat)
Developed 7.5 & 14 minutes in old, used Ansco 130, diluted 1+15.
The central 8x12" area was scanned (Epson V700); levels adjusted a bit , but NO sharpening.
I'd love to try the same test with portraits, but my bellows draw is wayyyy too short.
Here's how I mounted ont the camera:
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