 Posted: Sun Mar 18, 2018 7:55 pm Post subject: Re: Tominon 135mm F4.5 pancake copying lens, 37mm thread |
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danfromm wrote:
| e6filmuser wrote: |
My recent purchase via Ebay, total cost, delivered £13.80.
A large format, copying lens, it is optimised for 1:1 to 3:1. This is said to be the best version, the one with 10 diaphragm blades.
Three 90mm helicoids fully extended plus 122mm tubes. Total extension, including adapter, = 345mm giives 2:1 on full frame FOV=7.5mm, on m4/3 i.e. 4:1. WD = 180mm (7.5”) at x2.
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Interesting. I've had four of them, all for the Polaroid MP-4 system, all made to screw into the front of a Copal #1 shutter, all threaded M40x0.75. M37 x who knows what is a surprising new concept.
As I calculate it 3*90 + 122 = 392, not 345, and (392/135) - 1 = 1.9. Close enough to 2.
As I understand it, magnification = size of image on sensitive surface/size of subject. This is independent of the size of the sensitive surface. There's something about tiny chip digital cameras that turns perfectly sensible and intelligent people into something entirely different.
About MP-4 Tominons' optimizations, so-called. My Polaroid documentation lists the range of magnifications for which each lens will cover 4x5 when used on a standard MP-4 stand. They'll all give higher magnifications on the MP-4 XL. There's no mention of optimization. There's no reason to expect that the range of magnifications at which a lens covers 4x5 is the range its optimized for. |
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