Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: drwho520 on April 13, 2007, 10:14:37 am

Title: Canon PowerShot S3 IS - FOV
Post by: drwho520 on April 13, 2007, 10:14:37 am
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
Title: Canon PowerShot S3 IS - FOV
Post by: dobson on April 13, 2007, 03:58:51 pm
The equivalent focal length is just that; the equivalent field of view based on the standard 35mm frame size.

Your lens actually has a much shorter focal length (8mm?); but a very small sensor, hence the 6x crop factor.

In short, your FOV calculations should be correct, or at least close.