Noon 6x12 is great pinhole
I bought a Noon 6x12 pinhole camera from Poland via Ebay some months ago--and with a few modifications, it is now an excellent, unique pinhole camera. The pinhole is .33mm, so the focal length was around F180. Images are a tad fuzzy even for a pinhole, but the light distribution across the frame is probably better for the bigger aperture. In bright day light, exposures are usually between 3 and 4 seconds.
Initially, the camera was scratching the film, so I polished the two removable slats that frame the film inside the camera. The pinhole was made with a small drill that produced a fine hole, but one with very raised borders both inside and outside of the copper plate (painted black).
I removed the copper plate and sanded off the raised ridges around the pinhole (on both sides of the copper plate), trying also to thin the metal about the pinhole. As ham-handed as my technique probably was, the fine circumference of the pinhole was still there afterwards. I put the pinhole plate back in (centered as best I could), covered most of the exposed copper with flat black tape and tested the camera with B&W film (Fuji ACROS--least reciprocity of B&W films and great tonal range).
I also added some soft foam padding held in place with tape beside the take-up spool within the camera--to keep a sustained tension on the exposed film roll. Without it, the spools tend to unravel a little. I was damaging a good portion of my shots with light leaks when trying to get the exposed film from camera to dark storage.
I also countersunk the 4 holes in the bottom plate so that the plate rests flat on a tripod head. And added a bubble level and wrote the F stop on the top of the camera so as not to get it mixed up with other pinholes I use.
No more scratched or unraveling film and excellent ligthfall across the whole 6x12 frame (within reason for a pinhole). Images can be sharpened somewhat in Photoshop. I only today finally printed a shot taken recently, printed on 13 x 19 luster paper with an Epson 2200 in B&W setting. Very pleased with printed images (film scanned with Epson 4990). It is surprising--the printed image looks far sharper than pixel peeping of the negative scans would suggest.
The only draw back for the Noon 6x12 is its size and weight. It looks and feels like a big block toy without wheels. I've taken it to Yellowstone once and with the modifications, mean to take it back for landscapes.
I also bought a NOON 6x6 and repeated the whole procedure noted above. Although they are sold having a laser pinhole, mine was another microdrill with the raised rim around the pinhole. Sanding off the ridge around the pinhole (again both sides) greatly increase more even light toward image borders and resolution approaching the borders. The 30mm focal length Noon 6x6 produces very sharp images with a .2mm pinhole.