It’s a very small very thin pancake fisheye lens, It’s made to be a diagonal fisheye on aps-c cameras, and becomes a cropped circular on a 24×36 sensor, being too flat and thin not to include camera protruding parts and operator fingers in the field.
Projection is equisolid, diagonally it shows a bit more than 120 degrees, horizontally and vertically gives a small 105.5 x 71.48 field of view, and 12mm could be a better focal length value than it’s nominal one. As with other pancake lenses, like Olympus 9mm f8.0 “body cap” and the old 18mm f11 Pentax, it spots fixed aperture, and you have part of the body acting as light hood and limiting the fov if put pon a bigger sensor.
Construction is all metal and has 270 degrees turning focusing helicoid, which is not so usable, since it’s f8, and has no focusing scale.
In vr panorama use it needs a 8+8 two lines workflow, and due its NPP being so close to the camera’s tripod hole, not all panoheads will allow you to mount it easily.
It is Sold on eBay, Aliexpress, etc. I’ll let you find the bargain! 🙂
