Binoculars for eyeglasses: eye relief check

A worked example with the 16 mm line

Of the 529 binoculars in the chart with an eye relief figure, 337 list 16 mm or more. That is the count the tool shows when you enter 16 mm.

Enter 16 mm and the result reads that 16 mm meets the 16 mm the RSPB advises for people who wear glasses. Enter a smaller figure and the wording changes. A figure just under the line says the edge of the view may be cut off with glasses on. A figure well short of it says so plainly.

The chart holds 554 models in all, so some entries carry no printed eye relief. Those are left out of the count of 529.

How the check works

Nikon defines eye relief as the distance from the outer surface of the eyepiece lens to the position where the exit pupil forms, called the eyepoint. With glasses on, the lenses sit between your eye and the eyepiece, so the eyepoint has to sit further back.

The RSPB shop tells eyeglass wearers to look for at least 16 mm. The tool compares your figure with that line and prints one of three results: it meets the line, it falls just under, or it falls well short.

It then counts the binoculars in the chart whose printed eye relief is at or above your figure, so you can see how narrow the choice becomes.

What the makers and clubs say

Sources give slightly different ranges for good eye relief. The table sets out the figures the tool leans on.

Audubon says binoculars made for birders offer 15 to 20 mm. Swarovski Optik puts high-quality binoculars at 14 to 19 mm. Both ranges overlap the 16 mm line, which is why a figure near it is worth a closer look.

What to do with the result

If the figure meets 16 mm, look at the binoculars for glasses wearers to see which models carry it. The full binocular chart lets you narrow by size as well.

If it falls short, you may still get the full view with the right setup. Nikon's manual says eyeglass wearers should turn the eyecups to the fully retracted position, or fold back rubber eyecups. ZEISS and Swarovski Optik give the same advice to turn the eyecups in for glasses.

After the eyecups, Nikon sets the interpupillary distance by moving the tubes until the two fields form one circle. The diopter comes last. ZEISS says it is set once to correct different prescriptions in the two eyes.

Eye relief is one figure among several. Pair it with the exit pupil calculator for dusk use, or read what eye relief means and how to measure it. The binocular finder can filter by eye relief.