Lens Bubbles: Benoist Berthiot 100mm f2.2 Cinestar N2 Projection Lens

Thursday, June 16, 2016

Benoist Berthiot 100mm f2.2 Cinestar N2 Projection Lens

When I saw a beautiful portrait taken by Jérôme B. on Flickr with the Benoist Berthiot 150mm f3.3 cine lens, I was intrigued. I have always loved French lens. When I got a bunch of projection lenses from the camera show last time, and it included not one, but two French lenses, I was really happy. One of the lenses was a Benoist Berthiot 100mm f2.2 Cinestar N2.

Benoist Berthiot 100mm f2.2 Cinestar N2. My second lens project with the lathe, which turned out much better than the last one.

I assume that this lens was probably derived from a cine lens, since it has a name like Cinestar. The lens covers full frame, even at infinity. But the lens was really made for 16mm projectors, so even when there is no vignetting, the edges are mushy. But this is not a landscape lens, edge sharpness is not important at all. For the kind of pictures that are normally taken with a lens like this, rendering character is far more a consideration.

I put this lens on the lathe last night and turned it enough just to remove the grooves on the lens, and slip on a 37-52mm step-up ring, and it goes on a modified Vivitar 2X macro teleconverted helicoid. The lathe job is much much better than my last attempt. I used a 4-jaw chuck, and with the aid of a dial indicator, I was able to get the lens to turn pretty round, hence the much smoother finish.

Sitting at the dock of the lake - Benoist Berthiot 100mm f2.2 Cinestar N2 & Sony A7.

The lens hood I used was slightly too long, and it created some vignette at longer focus distance. That's completely OK by me. As expected, the center sharpness is very impressive. The rendering style is very much like the 150mm f3.3 lens Jérôme B used, so maybe they share similar optical designs.

This lens can create some interesting portraits, like the 150mm version does. I think I will explore more with this interesting gem.