I will be using a Canon PowerShot S3 IS for sky photos (it happens to be reviewed by Luminous Landscapes.) The camera will be set on a tripod in an upward looking oreintation and left to snap photos are regular intervals of 5-10 minutes. I am trying to figure whether a wide angle or fish-eye lens is necessary (they exist, I have seen them on Amazon) or if the camera in its stock configuration is capable. My concern is the FOV, or angle of view.
I know the standard equation for FOV angle (A) : A = 2*arctan(d/2/f). I am running into trouble with the focal length multiplier. The camera is spec on Canon's page does not have FLM listed. The shortest focal length is listed as 36mm - 35mm equivalent. This leads me to believe I can used the standard 35mm dimensions to figure field of view. Is this true? That would give me a 53 deg x 36 deg FOV.
Luminous Landscapes lists the FLM as 6, but I am assuming this is only for add on lens made for 35mm camera, which could come into play if I need to spec a wide angle or fish-eye. I guess I just need a sanity check.
--ty, DW