Yes, that's why it goes to the Stupid stuff section. The 12.5mm Computar lens is a C-mount lens made for CCTV/Machine Vision. I don't know of any C-mount lens in that focal range covering the whole 4/3 sensor.
The image is cropped from 4:3 to 1:1 and the lens works fine for anyone fond of square images (I am, many of images end up 1:1 or close to it). The G1 is a 12MP camera so composing for square images leaves you with 9MP to play with. Well, it works.
The lens is surprisingly sharp. The bokeh is a bit so-so wide open but fine from f/2. There are only three aperture blades and you can see that in the upper right of the image above. Most often that doesn't matter (and it makes company with Rollei). Medium contrast, it doesn't like stray light.
An equivalent FF lens would be, assuming 1:1 format, a 23mm lens. DOF-wise it would be a 23/2 then. Well, it's not bad at all considering the price; USD 25 plus a converter for another USD 25 and then half an hour of work at the kitchen table making it fit the adapter.
Another picture taken with the Voigtländer Ultron 2/40, this time with the Nikon D 200, showing a heavily fortified door in one of the entry gates to the Fort of Bidar/Karnataka @ f 2.8 ISO 320
