I don't know if this would be of interest but...

[Someonenameddavid]

Surplus Shed (www.surplusshed.com) has a few precision pinholes 25 and 50 microns at $50 a piece. I think that may be a little diffraction limited for photography, but I'm no expert

David

 

[jp498]

You can get "laser drilled" pinholes for pinhole photography for half that (or less) on ebay

 

[Dr Croubie]

Unfortunately not, a 0.05mm pinhole has an optimal 1.4mm (ish) focal length. Even push that out to a sub-optimal 5mm and it's still not going to cover much. Not good for much except converting tiny-sensored P&S Digitals. Maybe with a whole heap of them you could create a very funky Zone Sieve?

 

[NedL]

I'm not about to pay $50 for a pinhole but I've been exploring using smaller pinholes for macro work.

A couple weeks ago I made camera with a 0.15mm pinhole and about 100mm "focal" length, which is optimum for a "focusing" distance of somewhere between 1-1/4 and 1-1/3 inches. The magnification factor is around 3 at that distance. I made a picture of the insides of a pocket watch as a test and the detail was very impressive: the pocket watch completely filled a 5x7 paper negative. So I can imagine some uses for pinholes this small.

The most recent picture of mine for MSA was made with that camera, and it would have come out better with an even smaller pinhole. The hypo crystals were on a piece of glass less than 1/4 inch above the pinhole. The glass was 1/8" thick, so "focusing" distance less than 3/8" and magnification factor of maybe 15 or 20. If I'd had a 0.05 or 0.025mm pinhole I would have tried it!