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May 18th, 2004, 09:46 AM  #1 
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Join Date: Apr 2004
Location: Toronto, ON
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Widescreen "normal" fov
internet says:
A "normal" lens produces a field of view that is similar to human vision. The diagonal of the image plane is typically used as the reference for field of view determination. A "normal" lens has a focal length that is approximately equal to the diagonal measurement of the image plane. When the focal length is equal to the diagonal measurement it produces a diagonal field of view of approximately 53° which is similar to human vision.  But when we shoot widescreen then we can't use the diagonal of the image plane. so how much of the diagonal image plane of a widescreen has to be the focal length to produce a field of view that is similar to human vision? 
May 18th, 2004, 11:09 AM  #2 
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Join Date: Nov 2003
Location: Ashford, AL
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Why not use this calculator and run some numbers. As an example, the DV953 has a full wide focal length of 2.85 mm and a frame size of 18 x 24 (6 mm diagonal). An anamorphic lens is ~.67x or it produces a focal length of .67X2.85 = 1.91 mm. Run those numbers and see what you get. I believe the diagonal of the image plane stays at 6 mm because of the horizontal squeeze of the camera.

May 18th, 2004, 11:32 AM  #3 
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hmm with dry math, if I didn't get something wrong, I got that the focal length should be
sqrt(255/337) or about 0.8697 of the diagonal of the image plane of the widescreen .. nice calculator! =) I'm checking out right now I was looking for general solution.... but I guess for GS400 it won't matter much, and if there's minimal to no cropping the result will be more or less the given specs.. using the calc, I got that the GS400 has 1.8 x 2.6 mm active video matrix for TELE or this should translate to 1.8x 3.2 (assuming no or insignificant cropping) for WIDE. this means that while widescreen recording we have range from: 30.5 vertical and 51.73 horizontal FOV (about 60 FOV diagonal, and 60x0.8697 = about 52something (using the new found formula) which is about "normal" / and checking the TELE.. the diagonal is 52.8) to: 2.6 vertical and 4.63 horizontal degrees FOV 