M39 0.226mm Pinhole  Cap

Focal length: ~28mm
Min focus distance: ~1m
Aperture: ~F 127
Length (from flange): 3mm + 11mm for the adapter
Diameter: 58mm
Weight: 5gr.

Some pictures:

A7 and the pinhole cap on a M39 adapter.

A pinhole picture. No vignetting, the typical softness of pinholes in this format. No need to make more pictures, you can guess what you get.

This is a cheap plastic pinhole device in a M39 body cap.
There is no aperture setting and no focussing, the hole is 0,226mm diameter. The results are very soft, which seems to be typical for 24x36mm format pinholes. Pinholes for large format can be very sharp, however the exposure times are much longer. So I had a 0.1mm pinhole made (F~280) to see if the pictures would be sharper. I would say that it produces results which are even softer than the bigger pinhole. Obviously 0.1mm touches some optical limits, maybe it's diffraction. Here is a sample: