Notices

If you are going to give this a try, then the type of lens to use would be something like a C Mount. Those lenses have a rear thread of 1 inch I think, and the smaller ones are really small. They are used for a variety of formats (8mm, 16mm, CCTV, etc). Many people even attach them to digital cameras. The main hurdle is that the projected image circle usually doesn't cover the whole sensor. The best results are obtained with smaller sensors like a Micro 4/3. In the case of the Panasonic GH2, which is Micro 4/3, you can even obtain better results because it has a feature (I think it's called Teleconvert) in which only the center portion of the sensor is scanned. This allows these lenses to cover the whole active sensor.

Since these lenses are relatively small, can be had really cheap, and they are readily available, they are the ones you should use if you wish to experiment in my opinion.

I understand your approach. I personally don't think a C-Mount adapter would add that much heft to the case, especially if you can use a flat cover to screw on it when no lens is attached. You would need to experiment to see if this is feasible though. The distance at which the rear element of the C Mount lens needs to be mounted away from the built-in lens might impose some restrictions, or maybe even not be feasible at all. Some of the lens mounts for digital cameras extend the rear element of the adapted lens into the body of the camera, very close to the sensor. I have no idea how this would end up working with the N900. If you have access to a cheap C Mount lens, I'd say it would be a good chance to try out.


Well, that's too bad. Thank you for the heads up. The Chinese should sell a version of the camera module without an IR filter. That's an idea!