Re: pinholes for film canisters

I greatly appreciate all the input into the class suggestions, especially the concept of the same camera for all. They can explore latter if that is the intent of their
teachers. The leather punch is also a great idea.

Nick, I wanted to address a major safety concern to you. There is a general rule when using a drill, DO NOT use a drill greater in diameter than the thickness of the
material being drilled. Fortunately, I have scars, not stubs to remind me.

Also, why do you want to make such a large hole as 1/4” to overlay your pinhole on to?

I have professed to never having made a simple camera. As I thought about it, I have made one from a Caldwell candy tin with an oval footprint: 7”(h) x 5”(w) x
13/16” (21mm) (d).

I pre-drilled the can with a hole 1/16“ - 3/32” diameter. The pinhole was made of stainless steel foil tape approximately 1/4” sq. I wasn’t scrimping on tape, but
believed it would be easier to align the pinhole over the can hole.

The pinhole was 0.263mm, quite close to your desired 0.010” diameter. As I recall the needle needed to penetrate approximately 1mm through the foil to achieve
the correct diameter. To assure a perfect circumference, I placed the foil tape on a piece of mat board to drill. This provided a firm rigid material that would still
allow the needle to drill into it to the required depth. It offered adequate resistance to prevent deforming the pinhole, with a burr, tear, or wrinkled surface.

With thicker material as aluminum cans, I drill on top of a white art eraser. I use a swivel head pin vise that has 2 reversible collets capable of holding drill bits 0 -
1/8”. Its broad swivel top rest against the palm so controlled pressure can be applied.

Note, with needles, as with drill bitts, it is still important to drill with them rather than push them.

Back to my caliper issue, to achieve the exact depth precise measurements were necessary. The image shows what is possible with that focal length. On the lower,
the rounded shaded object is a nail head an inch or 2 away from the camera. Click the image to magnify again. Starting at the nail head scroll straight up from the
nail, through 2 trees and to my neighbors window approximately 125’-150’ away. I just realized there is a softness and fuzziness to this image, and I recall why. I
scanned the negative using Taco’s technique of holding a light bulb over a normal scanner using paper as a diffuser.

http://photoco-op.org/modules.php?set_albumName=album05&id=My_Porch&op=modload&name=Gallery&file=index&include=view_photo.php

Mike

-- 
_______________________________________________
Find what you are looking for with the Lycos Yellow Pages
http://r.lycos.com/r/yp_emailfooter/http://yellowpages.lycos.com/default.asp?SRC=lycos10
_______________________________________________
Post to the list as PLAIN TEXT only - no HTML
pinhole-discussion mailing list
pinhole-discussion@spitbite.org
FAQ at http://spitbite.org/pinhole-discussion/list.html