Half the weight, half the glass, one eye
A monocular is half a pair of binoculars, and the trade it offers is honest: it goes in a coat pocket, it costs and weighs roughly half as much, and it gives up the depth and the comfort that come from using both eyes. For a quick look at the Moon, for identifying what is on a distant ridge, or for carrying something optical without carrying a bag, it is the right tool. The specifications read the same way as binoculars — magnification × aperture, with the division between them giving the exit pupil that decides how bright the image is in low light. A small pocket monocular with a narrow exit pupil is a daylight instrument, whatever the listing implies about stargazing. Two figures matter more here than on binoculars. Close focus turns some monoculars into usable field magnifiers and is the specification that separates otherwise identical models. And weather sealing, published as a nitrogen purge or a waterproof rating, decides whether the instrument survives a pocket in autumn. Many current models are sold with a phone clamp; whether that clamp actually aligns a phone camera with the eyepiece varies far more than the photographs suggest. Read the eye relief if spectacles are worn, and read the prism type, which sets how much light survives the folding. We compare aperture, magnification, exit pupil, true field of view, close focus, prism and coatings, sealing, weight, phone adapter fit and supplied accessories.
10–30x zoom · 40 mm objective · 4 mm to 1.3 mm exit pupil
A zoom monocular running from 10x to 30x on a 40 mm objective, with BAK4 prisms, dual focus and a nitrogen-filled aluminium body.
Best for: Daytime viewing where one instrument has to cover several distances
≈ $36 / £28 / €26
10–30x zoom · 50 mm objective · supplied with phone holder and tripod
A 10–30x zoom monocular on a 50 mm objective, IPX7-sealed and nitrogen-filled, supplied with a phone holder and a metal tripod.
Best for: Daytime and dusk viewing with a phone, where the tripod does the steadying
≈ £31 / €24
16x magnification · 52 mm objective · 3.3 mm exit pupil
A 16x52 monocular with BAK4 prisms, SMC coatings and a nitrogen-filled waterproof body, sold for hiking, birds and concerts.
Best for: Daytime distance viewing where one hand has to stay free
≈ $25 / £29 / €21
25x · 30 mm objective · 1.2 mm exit pupil · decorative spyglass
A collapsible pirate-style brass-finished spyglass with a leather-wrapped grip, sold with a brass compass, a treasure map and a leatherette case.
Best for: A gift, a costume or a shelf — with occasional daylight use
≈ $27 / €35
12x · 52 mm · 85 m at 1000 m · 1/4-20 tripod thread
A 12x52 monocular with a 22 mm eyepiece, BAK4 prisms, twin focus rings and a 1/4-20 tripod thread, supplied with a case, strap and lanyard.
Best for: Anyone who intends to put a monocular on a tripod, which at 12x is most people
≈ €33
25x · 30 mm objective · 1.2 mm exit pupil · decorative spyglass
A collapsible pirate-themed spyglass in gold finish with imitation leather, sold as a set with a floating-dial compass needle, a treasure map and a case.
Best for: Role play, collecting and decoration, with daylight viewing as a secondary use
≈ €30
12x · 50 mm · 435 g · waterproof and nitrogen-filled
A 12x50 monocular with BaK-4 glass, UR coating, a twist-up eyecup and a nitrogen-filled waterproof body, published at 435 g.
Best for: A pocket instrument for dusk that is meant to be used in poor weather
≈ $130 / £96 / €79
12x · 55 mm · 352 ft at 1000 yd · IPX7
A 12x55 monocular with a 20 mm BAK-4 prism, FMC optics, IPX7 sealing and a supplied smartphone adapter.
Best for: Birdwatching and dusk viewing where the extra five millimetres of objective earn their weight
≈ $109 / £86 / €90
12x · 50 mm · 4.2 mm exit pupil · IP68
A 12x50 monocular with a fully sealed nitrogen-filled body rated IP68 to ten metres, BAK4 prisms and a raisable eyepiece for spectacle wearers.
Best for: Wet-weather use where a sealed instrument is worth more than an extra millimetre of exit pupil
≈ $45 / £40 / €50
Any figure written into the body of this page was true on the day it was written. The amount shown next to each instrument is requested from the retailer as the page loads, and it is that amount, not the text, that stands.
