Catadioptric versus conventional spotting scope

Q: I’ve been offered a second-hand Leupold spotting scope that features a catadioptric lens system. 

It’s a compact, ultralight unit about 19cm long and weighs only 350g or so. 

I’m sorely tempted to buy it, but will the optics be as bright and clear as a conventional spotting scope?

Arthur Reynolds

A: If the price is right, I’d advise you to buy that Leupold spotter. 

In conventional spotting scopes, magnification increases as the eyepiece and objective lenses are moved farther apart. 

The greater the distance the light travels from one lens to the other, the greater the magnification.

The catadioptric system uses mirrors to reflect the image back and forth several times. 

This increases the distance the light travels, allowing high magnification in a more compact package.