Kylietech 12x42 Fogproof

Is the Kylietech 12x42 Fogproof worth buying?

Yes, the Kylietech 12x42 Fogproof is worth buying at £25.99 if you want a 42 mm objective and 12x magnification and would rather not spend £30, and 18,949 owners rate it 4.5. The smartphone adapter, the twist-up eyecups and the dioptre ring all come at that price.

The Kylietech 12x42 Fogproof suits the daylight watcher: a walk, a nature reserve, a football match, a concert, a holiday full of birds you cannot name. It is a harder sell if most of your watching happens in the last hour of light, because a wider exit pupil, not more magnification, is what holds the image together at that point.

What does the 3.5 mm exit pupil mean in use?

Divide the 42 mm objective by the 12x magnification and the Kylietech 12x42 Fogproof leaves a 3.5 mm shaft of light at each eyepiece, and that is the figure that decides how the image looks in the evening. This pair carries a relative brightness of 3.5, and its field runs to 330 ft at 1,000 yds, which is what lets you pick a moving bird up again after it disappears behind a hedge.

Your own pupil opens to roughly 2 mm to 3 mm in daylight, so 3.5 mm keeps the Kylietech 12x42 Fogproof bright through the afternoon and usable on into the evening, while it does dim earlier than the 5.25 mm of a bigger-exit pair. The 21 mm eyepiece and the BaK-4 prism with fully multi-coated glass carry the light to that 3.5 mm without losing much on the way.

What comes in the box and what does it weigh?

The Kylietech 12x42 Fogproof weighs 550 g and measures 14.5 cm long, 12.5 cm wide and 3 cm deep, so it is a full-size pair that wants a neck strap rather than a coat pocket. A smartphone adapter comes with it and clamps onto handsets from 5.7 cm to 8.6 cm wide, and the body has a tripod mount for long sessions, though the tripod itself is bought separately.

Rubber armour wraps the barrels and absorbs knocks, and the objective covers stay tethered so they cannot be dropped in long grass. The eyecups twist up and down so glasses can stay on, each eye sets on the dioptre ring through plus or minus 5 dioptres, and the centre wheel takes the main focus.

Where does the Kylietech 12x42 Fogproof fall short?

The 3.5 mm exit pupil is the honest limit of the Kylietech 12x42 Fogproof. As the light goes, the image goes grey, and no coating or prism in this pair changes that. It has an evening margin rather than a dusk one.

At 12x every tremor in your hands is magnified along with the bird, so anything longer than a few seconds needs a hedge, a wall or a tripod under the pair. The 15 mm of eye relief is also tight for thick spectacle frames, and the body is water resistant and fog proof rather than sealed against a soaking.

How does the Kylietech 12x42 Fogproof compare with the Celestron Outland X and the Adasion 12x42?

The Celestron Outland X 8x42 at £85 costs £59 more and gives a 5.25 mm exit pupil against the 3.5 mm of the Kylietech 12x42 Fogproof, so it holds colour and detail far longer after sunset. It pays for that with magnification: at 8x it will not settle a distant identification the way 12x does. Buy the Celestron for dusk and a still view, the Kylietech for reach and £59 kept back.

The Adasion 12x42 at £64.99 costs £39 more and shows 367 ft at 1,000 yds against the 330 ft of the Kylietech 12x42 Fogproof, and it brings a tripod in the box as well. If you film what you find, the Adasion is the better buy; if you mostly look, the Kylietech does the same 12x42 job for £39 less.