Graflex.org

[Mustafa Umut Sarac]

Hello there, I saw an 3d printed 6X17CM camera with graflex optar 135mm f:4.5 lens. I loved the images , no vignetting or no visible corner problem. No need to discuss coverage.

I want to build laser cut plywood 6x17 cm box camera with this lens with infinity focused and f:22 used on tripod.

But I need to get more information to draw what laser cutter cut the plywood.

1- First of all , how should I mount the lens ? What is the best diameter hole in milimeters and what should be the plywood hole thickness. What is the minimum and maximum margin for thickness and diameter ?. I dont have the lens now and I should learn is it a single hole or is there a need to cut some strange shapes ?

2- I think lens shutter to film should be 135mm.

BUT Where is the shutter plane or blade ?

Is shutter located at the Front of the hole or middle of the hole or backside of the hole ? Please explain milimetrically
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Mustafa Umut Sarac
Istanbul

[William Hallett]

For mounting the lens, the lens should come with a threaded flange - a nut, essentially. You bore a circular hole (use a hole saw) the size of the outside of the thread on the lens, push the lens through, and screw the flange on to hold it in place. The Optar has a pin projecting from it to prevent the lens from rotating, so you will have to drill a hole for it to stick into - but don't drill the hole all the way through or you will have a light leak. If your lens does not have a threaded flange with it, you will have to find a machinist with a good lathe who can make you one.

As for the lens to film distance, you will have to determine this experimentally. There is no guarantee that 135 mm is the actual focal length of the lens. The nodal point should be in the plane of the diaphragm, but again there is no guarantee. If you want sharp pictures you will have to build some sort of focussing adjustment in.

Frankly, I do not think that the idea of a fixed focus camera for large format is very practical, because the depth of field of large format lenses is much smaller. Which is to say that if you get the thing properly adjusted to take a sharp picture at large distances, you will not get a sharp picture close up.
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WilliamH