Depth of Field – Moving a little bit out of focus.. so we can see only the picture without the background –> depends on the size of the aperture – small aperture = the spread is less more focused background and vice versa.
Field of View – increasing the focal length – zooming in makes a smaller FOV, should be used with a tripod to still stabilize , because a small shift in the angle corresponds to a large shift in the projected image.
FOV computation = d is the “retina”(sensor size) so computing the angle by arctan2((d/2)/f) will give us the FOV(angle width of view)
let’s say we have focal length f, Lens and Sensor width =d and image width= w..
If we want to match d with w.. so we have two unknowns z and z’
1 .We know that 1/z’ + 1/z = 1/f and we know can see that z = z’f/(z’-f).
2. d/2/z’ = w/2/z ==>z =w/d*z’
3. equating 1 and 2 ==> z’ = df/w +f.
