Wide Angle

Two questions really,

Is a fisheye just a ultra wide lens or is the glass different?

If one uses a 10 to 17 on a DSLR with a C (I think) sensor what would you actually be getting, I know there is a way to work this out but can't remember.

Been taking another look at lens and think a fisheye is a different type of lens to a wide, but would like conformation.

No, the lens is of different construction, a fish eye has a wider angle of view and the resulting image is distorted. I can only really talk about Canon lenses but the 15mm fish eye has a wider angle of view than the 14mm (non-fish eye) lens.

You need to muliply it by the effective ratio of the cropped sensor but to accurately answer this you would need to tell me whch camera you are enquiring about. Nikon use a 1.5x sensor (I think) and Canon use both a 1.3x and a 1.6x cropped sensor. On a 1.6x you would get an effective focal range of 16 - 27mm

Thanks Greyhawk the only info I have found at the moment is 23.4 x 15.6 and it is a 3:2 aspect ratio, is that any help?