Pentax Eyepiece Formula

A few people have contacted me in order to figure out the power ratio on fixed eyepieces with the Pentax Spotting Scopes. i thought I would do a post to put the info out.

The formula is as follows: Take the focal length of the scope and divide by the focal length of the eyepiece.

Example: 80mm (focal length = 500mm) divided by 14mm (xw14) = 35.71 or 36 power.

Focal length for the scopes is listed below
100mmED – 625mm
80mmED – 500mm
65mmED – 390 mm

Please feel free to call if you have questions.