Try electron microscope slides for apertures. They are precision holes in thin metal. If you buy direct from the manufacturer, they're about $25 for a vial of 100. I have twenty of them on one camera, and have seventy or eighty other single-shot cameras with electron microscope slide apertures. They're fantastic, especially when a bunch of cameras need to act the same and not be subject to the variability of hand-made pinholes.
Originally Posted by Grumpy Old Man
Earl Johnson sells them mounted for $1 each plus S & H.