For this Worldwide pinhole photography day I loaded a roll of Fuji Velvia 50 into my Pentacon Six and attached a body cap with a brass pinhole in it. This turns the camera into an 80mm pinhole camera. That's perfect as I can just use the sports finder for (approximate) framing.
The results are not half bad (my favourite is the shot above) and I think I'll go out with that combination again. But as you can see there's a reflection in all images. I assume that's due to the fact that I forgot to paint the backside of the brass pinhole black. I've now done that and hopefully the next roll will be better. I also found out that using the Pinhole Assist iPhone app while metering with an external light meter is really cumbersome. So maybe for the next roll I'll just print out a table of exposure times (with reciprocity failure) instead and put a new battery in my wrist watch for the complete "analog" experience.