JUPITER-12  2.8/35mm

Focal length: 35mm
Mount: Contax rf
Aperture: F 2.8 - F 22
Min focus distance: 0.9m
Length (see*): 38/40mm, including the adapter, lens protrudes 10mm from the adapter rim (see the end of the page)
Diameter: 56mm
Weight: 115gr.

*Contax mount is quite different. In fact it's two mounts. The inner mount has a focussing helical, so the standard lenses don't have one. The outer mount is for other lenses which have their own focussing device. Its difficult to measure. This one uses the outer mount.

Some pictures:

A7 and the lens.

This is a second, earlier version of the same lens. It reads JUPITER-12 1:2.8 F=3.5cm.

Sample pictures: You may click on the sample image (except closest focus) for full resolution. The full resolution image opens in a new window, so you can keep it open for comparison. Focus is on the satellite dish to the right of the big solar panel near the center of the photo.

F 2.8.

F 8.

F 22.

Closest focus  is 80cm from outermost edge of the lens, F 8. Focus on the program wheel of the camera.

In my opinion this lens is a deception for full format digital. As far as I remember the M39 variant delivered quite good results on film with a Bessa L. It's based on the famous Biogon design; there are good evaluations on the web that I can't confirm. It is soft wide open. Closed down it's better in the center, but there is flare at the edges, see the lower left corner. Maybe the design isn't good for full format digital, just as the old 15mm Heliar. I own another Contax mount and  M39 variant of these, they have the same problems. The lens has no close focussing capablities. However it is small and lightweight.

The Contax rf mount adapter is difficult to find and sometimes expensive, but Contax mount lenses are often much cheaper than their M39 versions. These 2 lenses were very cheap and I already had the adapter. Otherwise there is no real advantage in comparison to the M39 model which weighs less for the combination adapter/lens.

As this lens has an enormous protruding rear element with an unprocted glass, it has to be handled with care. The A7 has just, but just enough room inside for my version of the lens, check yours at your own risk. For security reasons set the lens to closest focus while attaching it, which shifts the back part inside for 2mm, at least it does on my versions, there are people who claim the opposite. Anyway, it still sticks out of the adapter's outer rim. So if you want to use it on another model of camera, please check. There is not enough room for it in the A5000. If you don't have the special rear cap: an empty transparent plastic film container from 35mm film cut to half the hight will perfectly stick and protect the back of the lens.