| v1d9uy |
i found a beseler lens says its a 135mm 1:5.6 enlarging lens
but says nothing about FOV i have no idea what the 1:5.6 means
im no optical expert. |
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| dnsey |
1:5.6 means that the aperture is f/5.6.
To estimate the FOV, take the lens outside, and hold it to focus a view of the surroundings onto a sheet of paper. You'll see quite easily where the brightness drops off. Allow 10-15% smaller radius for practical use (to compensate for the eye's poor ability to judge such things). |
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| v1d9uy |
| my problem is i dont have it ... but i can get it for $30 |
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| dnsey |
It's impossible to tell what the FOV will be without further information.
A serial number might enable you to track down the design, or if you know the original application that will give you a good clue.
If I had to guess, I'd say that an 'enlarging lens' of that FL was either for a medium-format enlarger (6 X 9 cm?), or a process camera (W/A lens for A3+ format). |
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| Guy Grotke |
| These are generally too small in diameter to use, unless you have a short-arc lamp. If you really need a 135 mm lens (for a tiny LCD?), then I would look at surplusshed.com. But I have no idea where you would find fresnels to match that short a focal length. |
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