I was looking for a shutter for a DIY medium format camera and found this forum and your posts. As a machinist I can really appreciate your excellent work. Looking at your posted pictures I saw a Computar lens. I may have this lens. I have an optics bench and fiddle around with optics. I bought two Computar lenses from Surplus Center so I could make a camera. You say that your lens needs to be used with a bellows. Though I want to make a camera with a bellows I would like to know why this lens needs to be used with one. Any advice you can give about where to start looking for info about a DIY camera is greatly appreciated. And once again, great work on your DIY camera.