Exit Pupil Calculator

Exit pupil = objective lens diameter ÷ magnification. Larger exit pupils gather more light — useful for dawn and dusk deer stalking. The human eye dilates to ~7 mm in darkness; an exit pupil above that wastes light without benefit.

Exit Pupil

4.17 mm

Good — suitable for low-light field use

Quick presets

Exit Pupil Reference Guide

Exit PupilSuitability
> 7 mmExceeds eye limit — wasted light but no penalty
5–7 mmExcellent — full light capture in low light
4–5 mmGood — suitable for dawn/dusk stalking
3–4 mmDaylight and bright twilight only
< 3 mmDaylight only — not suitable for low-light field use
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