As for many of these 16mm projection lenses there is not much information to gather. This 75mm lens almost covers a full frame sensor. It has a classic Petzval optical design with 4 elements in two groups, giving it the classic swirly bokeh. This means also that the focal plane is curved (also called field curvature), which makes it difficult to nail focus especially at the edges of the frame. This can be quite hard to work with, and it takes some time getting used to. At least for me personally. The lens itself is also super easy to take apart to clean and it’s mainly made out of brass, which surprised me a bit.
Adaption
This lens has been in my drawer for a long time. I tried adapting normally with existing parts, but soon found out this lens needed some special more expensive parts. Which at the time I didn’t want to spend. But the lens eventually piqued my interest once again.
The main problem was finding parts that were compact enough to be able to focus to infinity. I had about 40-50mm to work with. I also found out that the normal M42 super slim adapters for E-mount would not fit. This is because the projection lens is 42.5mm in diameter. I found a handy 52mm to E-mount reverse adapter, that is usually used to reverse lenses to the camera body for macro work. Then I had to remove a bit of the threading from the projection lens for it all to fit. I also had to remove a small amount of metal from the reverse adapter. With this I had to find a small focusing helicoid that was M52 at both ends. Unfortunately I could not find this any cheaper than about $60-70. With this the lens was ready for usage, with infinite focus.
These are the parts I used to make the adaption:
- 42.5 – M52 clamp adapter from RafCamera
- Compact M52-M52 focus helicoid
- 52-52mm female reverse adapter
- 52mm to E-mount reverse adapter
Lens Characteristics
It acts like a normal 16mm projection lens, sharp in the center, and because of the field curvature it gets more and more unsharp the further you go from the center. This makes it especially hard to nail focus. Also if you get long enough away from the center it will be impossible to even get the subject 100% in focus. Either way it works great for portraiture photography, and the blurry effect the field curvature gives helps in this regard. In my opinion.
The lens has been coated in some way, which means it is a little better for flare control when shooting at high contrast surfaces and towards the sun. There is still a large amount of lens flare, but this also can be used for your advantage.
Bokeh is especially important for lots of people shooting with projection lenses. The bokeh characteristics of this lens does not disappoint, with lots of swirly bokeh. And with almost a full coverage of the image circle at full frame the bokeh becomes even more pronounced.
Summary
I absolutely love this lens, it feels sturdy, the images are beautiful and it is relative easy to operate. 16mm projection lenses that (almost) cover full frame sensors have always had a special place in my heart, because they are far and few between.
Pros
- Sharp in center
- Good contrast
- Coated optics
- Swirly bokeh
- Almost covers full frame
- All metal body
Cons
- Heavy field curvature
- Unsharp edges
- Destructive modification
- A bit hard to adapt