Art supply and hobby shops used to have rolls of tape that were very fine 1/16" (1.5mm) wide. They were used for pin striping car models and other things. I think they'd be useful, but they will look pretty bold in your viewfinder.
Secondly, I'd recommend an X-Acto knife with a #11 fine point blade to make the permanent lines. I think it will give you a narrower line than something like a compass point AND since the surface of the finder screen is not smooth (the fresnel ridges) it should cut across them without making a wiggly line. I'd put a steel ruler with a cork back (to avoid scratching the screen) across the screen, then scribe.
Remember to scribe on the bottom of the screen where the image is formed otherwise your lines may be a little fuzzy.
Mr. Bill
Kotsinadelis, Peter (Peter) wrote:
Malcolm Stewart wrote:
Hi Peter,
I wondered how long you'd stay on the list with all the unwanted(?) and unwarranted advice about paper size economics etc! I've put markings on a microscope slide cover slip (clear glass, 0.17mm thick, 19mm diam.). I used a diamond tipped marker (designed for the postcode marking of valuables), and using very light pressure against a straight edge I got my lines. I pressed too hard on the first sample, and it cracked, but no. 2 is OK and is in use. Your focus screen is plastic so you should be able to use a sharp steel point instead of a diamond. Biggest problem is getting the lines straight so that when seen in your viewfinder, they still look reasonable. (My usage was adding a reticle to a telescope eyepiece - and getting it gently illuminated with a dim LED is still proving a problem.) How will you know that you've put the focus screen back in the correct register ? I'm thinking about your scribed lines raising the plastic ever so slightly around the lines, and disturbing the register. Does the screen have metal edges? ------------------------------------------------------------------------ -------------------------------
Hi Malcolm,
What I am thinking is really to places 2 vertical lines on the screen,
one on each side (left and right). The screen is plastic, no metal
aournd the edges. This will provide the boundaries for an 8x10 (or 4x5)
and I can then photograph accordingly. Since the viewfinder is about 97% on my EOS 3 (thank god its not 100%, I
avoid cameras with those) I should be in good shape.
To set the lines and ensure the screen registers correctly, my somewhat
crude method will be to place small strips of tape first and install the
screen to see if it lines up properly. I'll focus on an 8x10 on my wall
to see where the framing is and when its correct, then mark lines.
Peter K
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