I’ve had this old brass lens sitting around for years and I’m curious to see what kind of image it will make. Just how to put it to good use is a bit of a puzzle. The lens is very simple. Just two elements bookend a fairly rudimentary but clever aperture system. There are three tabs (of which you can see two in the photo above) sticking out of the lens barrel. These tabs each pivot a different sized stop into the central opening. The tabs are numbered (3, 5, 7), but obviously don’t correlate to familiar f-stop values (the numbers get larger as the size increases).
Otherwise, that’s it. No shutter or focusing mechanism.
The most natural fit for this lens is on a 4x5 camera. Mounting would be as easy as crafting a simple lens board - there’s no way this lens will require precision alignment. However, the lack of shutter means I would have to use some kind of lens-cap-as-shutter trick. Quite feasible if my exposures can be kept in the several second range.
My other option would be to rig a mount for my Mamiya. This would be a challenge as I’d have to create a way to move the lens for focusing (and while I’m at it maybe swings and tilts). The benefit to all this work would be that once set up, shooting would be easy using the camera body’s metering system and focal plane shutter. Plus, digital capture would allow immediate results and lots of freedom to play.
There are pros and cons to both paths but in my mind the correct answer is clear.
My first step will be to get the lens on a workbench. There I’ll figure out the approximate focal length an get a sense of how large an image it projects. I can also translate the aperture measurements to f-stop values and get a sense of what my exposure times might be on the 4x5. I’ll document this process and post more in the next few days.