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  5. Sport Optics Guide -Fieldscopes-
  6. How to Choose Fieldscopes
  7. How to choose eyepieces

How to Choose Fieldscopes How to choose eyepieces

Magnification is determined by the combination of Fieldscope body and eyepiece.
Eyepieces are available in various types including a wide type that has a fixed magnification, and a zoom type with non-step adjustable magnification.

Magnification of Fieldscopes

The magnification of a Fieldscope is determined by the combination of the body's effective diameter of the objective lens and the eyepiece. Eyepieces are available in various types including a wide type or a zoom type, and eyepieces for digiscoping have also been developed. Choose the appropriate magnification according to your needs.

Combination examples of eyepiece and magnification

Eyepiece Wide type: fixed magnification (low magnification) Wide type: fixed magnification (high magnification) Zoom type
Recommended for observing near and wide-moving subjects. Recommended for observing distant subjects, details and for fixed-point observation. Non-step adjustable magnification from low to high.
Effective diameter of the objective lens 85mm 65mm 85mm 65mm 85mm 65mm
Magnification 20x 16x 75x 60x 20-60x 16-48x
Field of view*
20x

75x

20-60x
  • *When using 85mm effective diameter of the objective lens
  • *Photos are simulated viewfinder images.

Comparing zoom type eyepiece and fixed magnification eyepiece

A Nikon's zoom type eyepiece allows you to adjust the magnification at any position from low to high and lets you enjoy various magnifications. Compared with a fixed-magnification eyepiece, the field of view of a zoom type eyepiece is narrower, however, if you plan to use a Fieldscope in a variety of situations, it is recommended for your first eyepiece. A fixed-magnification eyepiece is designed to secure a wider field of view. You can choose the most appropriate magnification eyepiece according to your particular needs, and you will obtain high-quality images whichever strength you select, because the optical structure is optimized for each magnification.
If your observation conditions are fixed and require a wider field of view, or for digiscoping where vignetting must be minimized, fixed-magnification eyepieces are recommended.

The field of view comparison between a zoom type eyepiece and a fixed-magnification type eyepiece.

A zoom type eyepiece can be set at several magnification positions within the zoom range.
Compared with a fixed-magnification type at the same magnification, the field of view of the fixed-magnification type eyepiece will be wider.

Field of view: fixed-magnification type at 20x
(Field of view at 1,000m is 58m)

Field of view: zoom type at 20x
(Field of view at 1,000m is 38m)

  • *When using 85mm effective diameter of the objective lens
  • *Photos are simulated viewfinder images.