Fisheye MC Zenitar-N 16mm f/2.8 Lens

31 January, 2013

The Zenitar 16mm f/2.8 is a manual focus/aperture full frame fisheye lens manufactured in Krasnogorsk/Russia. The full frame (the covered rectangle of the projected image circle) covers 180 degree FOV in diagonal on 35mm. See http://wiki.panotools.org/Fisheye_Projection and http://wiki.panotools.org/Special_issues_with_fisheye_lenses. The lens is available for different mounts (M42, Nikon, Canon, ...). Zenitar-N is the model with a built-in Nikon F-mount and that is the model I ordered:

Here it is. Arrived in a weather proof bag from Russia:

Protected against the mail carrier:

With the seal already broken:

Inside the nylon case:

Wrapped in paper and authentically Russian manual:

And individually certified:

And it fits on the Camera (Nikon D-50)

With three additional color filters available

which get screwed in (at the F-Mount side):

But there was problem. The lens didn't focused to infinity. Instead the lens focused from 0.05m to about 1m. The picture were really sharp there, almost like a macro, but no one needs a fisheye macro. Sending back the lens? I already waited three weeks.

Why does the lens doesn't focus at infinity? For some reason the distance settings ring wasn't aligned with the lens setting. Infinity for the distance ring didn't match the position for the internal lens ring. See the left drawing. With the wrong aligned distance ring, the distance range of the lens is shifted from 0.3m-infinity to 0.05m-1m.

How to fix this? The distance ring needs to be aligned with the internal lens ring to allow the lens to be focused to infinity. This is illustrated in the right drawing. With the new aligned distance ring, the infinity distance can now be set. The minimal distance moved up from the 0.05 to the 0.3m.

The first step is to move back the rubber ring of the distance ring. Do not use any sharp tools, just slide the rubber back on one side a little bit and go around in a few circles to move it back slowly. On the lens barrel you will see three small holes (every 120 degree around the barrel) with a very small screw inside.

There are also three very tiny holes for the lens hood. Be careful with the tiny screws. Choose a screwdriver that matches the size perfectly. Do not use one that is too small. You might break the screw. (You screw up the lens!).

To have the lens focus to infinity, the lens hood needs to be adjusted as well. When you rotate the distance ring to infinity, the lens barrel extents towards the lens hood and might be blocked there preventing the lens extending to the infinity setting.

Don't remove the screws holding the distance ring. Just unscrew until the distance ring moves without being attached to the internal ring. Rotate the distance ring towards a smaller distance and tight the screws just to move the internal ring towards infinity. Look at the illustration above. You are moving the outer distance ring to shift the internal distance ring. For the lens I received the infinity settings was exactly at the stop position of the internal distance ring. I had to move the ring as much as possible towards the infinity setting and the adjust the outer distance ring to match the red mark with the infinity symbol. Once this is done, carefully tight the screws and slide the rubber ring back.

The Nikon D-50 for example cannot meter with this lens and the internal flash is disabled. You need to use the manual setting, set the exposure time manually and use an external flash (SB600/800) set to manual mode if you want to use a flash. At f/5.6 the lens seems to have an optimal aperture.

Some samples: