My C mount lenses

These are small TV lens, or some people call them CCTV lens, or C mount lens. Like all the other lenses, prime lens work better in terms of image quality and they are usually faster in terms of aperture.

Currently, I would say:

1. 2.3-6mm Compustar: for really wide field monitoring, in my 1/3" DMK 31AF03.AS, it even gives some fisheye view effect

2. 6mm Cosmicar and 25mm Fujinon: they allow the attachment of a B+W IR pass filter to do some interesting project, like IR astronomy. 6mm is wide enough for wide field and 25mm is close enough as medium power.

3. 75mm Fujinon and 150mm Cosmicar: they are more useful as guidescope now, and the 2-stop faster aperture of the 75mm should be great for field with only dimmer stars, and the 150mm is also fast enough for most cases which should allow me to guide my Canon 200mm f2.8L since the DSLR has bigger pixel.

4. Vivitar 1.5x: seems like useless now...