Graflex Optar 135mm f:4.7 Flange to film distance ?

[Mustafa Umut Sarac]

Graflex Optar 135mm f:4.7 Flange to film distance ? Some reports 130mm , some other 122mm ? What is the truth ?

 

[Alder Statesman]

130mm. Not much on the film plane side of the lens.

 

[Mustafa Umut Sarac]

130mm. Not much on the film plane side of the lens.

Thank you very much Alder , now I can draw the camera. Thank you.

 

[Dan Fromm]

Thank you very much Alder , now I can draw the camera. Thank you.

That's what you think. Your problem is that you believe a lens' actual focal length is the number engraved on the trim ring. Equivalently, you believe that the flange-focal distance of your lens is exactly the flange-focal distance of the lens that belongs to the person who advised you. This is rarely quite the case. You have to measure a lens focal length before making fixed focus camera to use it or you have to be able to focus the camera through the lens so that you can set the lens-to-film distance so that it focuses at the desired distance. Or beg/borrow/steal a view or press camera to use to measure flange-focal distance at the desired focusing distance.

 

[Alder Statesman]

That's what you think. Your problem is that you believe a lens' actual focal length is the number engraved on the trim ring. Equivalently, you believe that the flange-focal distance of your lens is exactly the flange-focal distance of the lens that belongs to the person who advised you. This is rarely quite the case. You have to measure a lens focal length before making fixed focus camera to use it or you have to be able to focus the camera through the lens so that you can set the lens-to-film distance so that it focuses at the desired distance. Or beg/borrow/steal a view or press camera to use to measure flange-focal distance at the desired focusing distance.

Hard for me to photograph, but the lens in question, on my Crown Graphic is 120mm from the flange on the rear element to the film plane.

 

[Dan Fromm]

Hard for me to photograph, but the lens in question, on my Crown Graphic is 120mm from the flange on the rear element to the film plane.

The flange-to-film measurement is conventionally made from the back of the shutter (= front of lens board) to the film plane.

 

[Alder Statesman]

The flange-to-film measurement is conventionally made from the back of the shutter (= front of lens board) to the film plane.

Just trying to help as I had the lens in question sitting on my coffee table.