Re: [Frameworks] JK printer settings for 8mm to 16mm blowup

From: eric stewart <>
Date: Mon, 10 Oct 2011 22:46:44 -0700

What kind of a lens are you using? I believe the proper lens to use for
optical printing is an enlarging lens. Camera lenses have different number
and arrangement of optical elements. I have used a 50mm slr lens to blow up
s8 to 16 and it required a ridiculous amount of extension tubes, like
200mm+, and it requires that you be like one millimeter away from the film
strip, which is not practical if your using the jk's gate.
If you are using a camera lens with bellows or extension tubes what you are
doing conveniently falls into the realm of macrophotography. There are a
variety of equations to figure out how much extension you need and what your
focus distance is, some quick google-ing should present them. Simply put
the farther away the lens from the film plane, the greater the magnification
and the closer the focusing distance.
Here is a link from the jk website describing the use of enlarging lenses,
although I don't immediately understand it:
I have some old manuals, and educational material relating to the jk lying
around somewhere, I will try to dig them up and see if I can find anything
relevant to your predicament. In the meantime i would just get ridiculously
close to the super 8 your trying to photograph. It will be elusive, the
depth of field is so shallow that minor movements will send you back into
the unfocused blurry world.

-Eric Stewart

On Oct 10, 2011, at 6:47 PM, John Woods < <>> wrote:

Hi Frameworks, I'm at last attempting to do some Super 8 blowups to 16mm but
am confounded at finding the right printer/lens/bellows configuration. I've
attempted to do the setup recommended by JK at:
with no luck, I just get a blurry grey image. I'm using a 50mm lens and tube
extensions on a K-103 model.

If anyone has any tips or could share with me a workshop manual being used
by your school/co-op it would be greatly appreciated! I've found a few
official manuals online but none that go into detail about doing blowup

Thank you.


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Received on Mon Oct 10 2011 - 22:47:05 CDT