Half the weight, half the glass, one eye · review

Czemo LJL-DTWYJ 10-30x50 review

A 10–30x zoom monocular on a 50 mm objective, IPX7-sealed and nitrogen-filled, supplied with a phone holder and a metal tripod.

By Jean-Benoit Buisson

The bottom line A zoom monocular sold with the support it needs, and with two mutually exclusive figures for its field of view.

The set is the point

A 10–30x zoom, a phone holder and a metal tripod with a pan head, in one box. At the top of the zoom range, a hand-held monocular shows very little; on a tripod it shows what the optics can deliver. Supplying the support rather than selling it separately is the sensible decision here.

The exit pupil across the range

Fifty divided by ten gives five millimetres — the classic astronomy figure. Fifty divided by thirty gives 1.7 mm, which is dim and fussy. The instrument is at its best at the wide end and increasingly compromised towards the narrow one.

Two figures that cannot both be true

The same bullet prints an “ultra-wide field of view” of 130 m at 1000 m and an angle of 5.6 degrees. Those correspond to about 7.4 degrees and about 98 m respectively. Both are reproduced above, and neither is chosen.

The sealing

IPX7 with a full nitrogen filling, and the maker adds a sensible caution: do not rinse it or submerge it, to extend its life. That caveat sits oddly beside an immersion rating, and it is quoted here because the maker writes it.

Availability

German, French, Italian and Spanish Amazon stores ran from 24 € to 31 € on the day of the survey.

British Amazon store lists it in local currency, which the euro range above sets aside.

American Amazon store gave no result whatever, so the buy button there opens a search rather than an empty page.

Figures as Keepa reported them on the day this page was last updated. Stock and pricing shift without warning.

Prices quoted in this text were read on 17 September 2026. The live price is at the top of the page.

What it publishes, and what it withholds

Strengths

A tripod is supplied, which is what a 30x zoom actually needs
At 10x the 5 mm exit pupil equals a good astronomy binocular
The phone holder and tripod together make steady phone photography possible

Compromises

The two published field-of-view figures contradict each other
At 30x the exit pupil falls to 1.7 mm and the view dims accordingly
A supplied tripod at this price is a small one, and the listing gives no height

Specifications

Aperture	50 mm
Magnification	10x to 30x, variable
Exit pupil	5 mm at 10x falling to 1.7 mm at 30x
True field of view	The listing gives both “130/1000 m” and “5.6°” — those two cannot both be correct
Close focus	Not published by the maker.
Prism	BAK-4 prisms with multi-layer FMC coating
Coatings	Not published by the maker.
Sealing	IPX7, 100 % nitrogen-filled per the maker
Weight	Not published by the maker.
Phone adapter fit	Not published by the maker.
Supplied accessories	Phone holder and metal tripod with a pan head
Amazon reference	B0BMV2C17V (same reference on 5 Amazon marketplaces)
EAN	0785957653522

What observers ask about this one

Which field of view figure is right?

Neither can be confirmed here. A hundred and thirty metres at a thousand is about 7.4 degrees; the same listing also prints 5.6 degrees, which would be roughly 98 m. This page reproduces both and settles neither.

Is the supplied tripod adequate?

It is the reason to buy this set, and no height or load figure is published. At 30x even a small, stable support changes the view more than any optical difference between monoculars of this class.