Angle of view for a 25mm CV lens

[lxmike]

Hi, what is the angle of view for a 25mm/4 skopar snapshot and also what is the angle of view of the 21mm. I have only ever used a 28mm which has an angle of view of 74 degrees.

thanks in advance Mike

 

[drew.saunders]

Horizontal, Vertical or diagonal angle of view?

The math is 2* arctan (half of film part in question/lens focal length)
So, for a 25mm lens on 24x36mm film (43mm diagonal)
Horizontal is 2 * arctan (18/25)=74 degrees
Vertical is 2 * arctan (12/25)=51 degrees
Diagonal is 2 * arctan (21.5/25)=81 degrees

For your 28 to have a 74 degree angle of view, that's based on the diagonal, which makes it easier to give just one number, but who composes based on the diagonal?

Drew

 

[lxmike]

thanks drew

 

[lxmike]

wow, is all I can say, what a lens and angle of view