Monoculars
A fixed 12x, or a zoom that contradicts itself?
A fixed magnification gives one exit pupil; a zoom gives a range, and at the top of that range the beam narrows sharply. One of these publishes its field of view cleanly; the other publishes it twice, in two forms that do not agree.
| Compared on | Piper 12x55 (QHMN001) | LJL-DTWYJ 10-30x50 |
|---|---|---|
| Aperture | 55 mm | 50 mm |
| Magnification | 12x, fixed by the design | 10x to 30x, variable |
| Exit pupil | 4.6 mm — 55 divided by 12 | 5 mm at 10x falling to 1.7 mm at 30x |
| True field of view | 352 ft at 1000 yd, as the maker publishes it | The listing gives both “130/1000 m” and “5.6°” — those two cannot both be correct |
| Prism | 20 mm BAK-4, per the maker | BAK-4 prisms with multi-layer FMC coating |
| Coatings | Fully multi-coated | Not published by the maker. |
| Sealing | IPX7, nitrogen-filled per the maker | IPX7, 100 per cent nitrogen-filled per the maker |
| Supplied accessories | Smartphone holder, hand strap | Phone holder and metal tripod with a pan head |
A tick means one listing published something the other did not, or published a better figure. It does not mean the product is better, and the column is not a score out of anything: a maker who says less loses lines here without losing a comparison. The two verdicts below are where the page is settled.
The one whose figures agree with each other. A fixed 12x on 55 mm gives 4.6 mm of exit pupil at all times, and the field is published once, in one unit. Fully multi-coated is the strongest of the four coating labels and it is stated.
The one with the range, and the contradiction. Ten to thirty times on fifty millimetres is a wide span, and at the top of it the exit pupil falls to 1.7 mm — dim, and unforgiving of hand tremor. Its field of view is printed two ways that cannot both be right, and this page reproduces both rather than choosing.
Exit pupil is aperture divided by magnification. At 30x on 50 mm it is 1.7 mm, which is a narrow beam: the image dims and the eye has to be positioned precisely.
A field of 130 m at 1000 m is about 7.4 degrees; 5.6 degrees would be roughly 98 m at 1000 m. They describe different instruments, which is why this site prints both and resolves neither.
At 30x, yes — it is the difference between a dancing image and a still one. A small metal tripod is limited, and it is better than holding the monocular at that magnification.
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
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
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.
