When choosing focal length
, consider the following:
: a lens
with a shorter focal length is less expensive.
Depth of field capability
: A longer focal length provides less depth of field
; a shorter focal length lens provides more depth of field.
: A longer focal length lens provides a less distorted image. Gauging and pattern matching tools are sensitive to distortion
. In the image to the right, notice the image distortion from the 4 mm lens.