Choose by effective diameter of the objective lens
How to Choose Fieldscopes
The larger the effective diameter of the objective lens is, the greater the light-collecting power. This results in a brighter and higher resolution image. Especially, the higher magnification is, the better the large objective diameter will be as far as brightness is concerned. The differences in brightness produced by the effective diameter of the objective lens become more noticeable in low-light conditions such as at dusk or dawn. Usually, a large-diameter objective lens will make a Fieldscope bigger and heavier.
Nikon eyepieces can be used with any Nikon Fieldscopes as long as they share the same mount system.* The magnification and real field of view of the same eyepiece would vary according to the effective objective diameter of the attached Fieldscope.
- *For details, please refer to the product information page.
Fieldscope weight
The larger the effective diameter of the objective lens is, the greater the Fieldscope's length, width and weight.
As long as you are observing from a fixed point, there is no need to worry about the weight. However, if you observe/shoot (digiscoping) at several positions, carrying a Fieldscope may become difficult. Choose the appropriate Fieldscope according to subject and the viewing environment.