Binoculars reviews

Endurance test of 8x42 binoculars

30 April 2013
Arkadiusz Olech

6. Delta Optical Forest II 8x42

Endurance test of 8x42 binoculars - Delta Optical Forest II 8x42

The Delta Optical Forest II series was launched in 2011. At first it consisted of 42 mm models; then it was enlarged by the 50 mm binoculars. We tested the Delta Optical Forest II 8x42 and its result, in the traditional part of our procedure, amounted to 109.2 points. If you take into account the fact that you deal here with a cheap roof prism instrument such a result should be considered as pretty good. Still the cheapest series of binoculars, produced in China, often feature poor mechanics so we were very curious how the Forest II would fare in our endurance test.

Low temperature

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After 24 hours spent in a temperature of -22° C several problems occurred. First of all the central focusing wheel started to move with a significant resistance – you could forget about setting the focus using just one finger. In order to change its position you had to use the whole hand. The individual focus ring (for dioptre regulation) froze over completely; you weren’t able to move it, no matter how strong you turned.

The eyecups regulation, the tripod mounting blockade and the gauge of the tubes didn’t cause any problems for a change – here everything worked as it should.

High temperature

When it comes to the central wheel, its work wasn’t an issue; it moved fine, without any squelching, grease leakages or slacks; the problem was that the rubber padding of the binoculars swelled under the heat and it started to block the wheel. When we tried to focus we encountered a noticeable resistance and heard some squeaking of the rubber. The dioptre correction ring worked well for a change; we also didn’t have any reservations about the eyecups regulation and the work of the tripod mounting blockade. We didn’t notice any grease stains, either on the casing or inside the tubes, but during the gauge regulation you could hear distinct squelching. When it comes to the mechanical damage, in this part of the test the Forest II series logotype badge fell off from the casing – you can see it in the photo below.

Endurance test of 8x42 binoculars - Delta Optical Forest II 8x42

Waterproof qualities

Here we got a nice surprise. Although the producer states in the specifications that the binoculars are waterproof, in this class of equipment it usually means splash proof – the device can be used in moderate rain but certainly it cannot be thrown into water. Meanwhile the Forest II managed to survive one hour of submerging without any problems; mind you several of its renowned rivals, declaring full waterproofness, didn’t fare as well.


Two falls from different heights didn’t cause any outer mechanical damage. The only thing we managed to spot was very slight decolimation (on the detection level border)

Optics cleaning

At this price point it would be strange to expect high quality hydrophobic coatings so the results are hardly good. Water residue, which got stuck after applying high temperature, was very difficult to remove and needed a special cleaning fluid. The fingerprints were removed only after several intensive swipes of a dry cloth. The water didn’t dribble from the elements, leaving distinct droplets behind . The grease can be smeared on the lens and is difficult to remove; still you could get rid of it without the cleaning fluid.


No other flaws.


The chart below shows the results the tested pair of binoculars got in particular categories:

Low temperature:
High temperature:
Waterproof quality:
Optics cleaning:

The Delta is a kind of Cinderella device here – it managed to surprise us very nicely. The weakest result it got in the cleaning category. Small wonder: high quality hydrophobic coatings are the last thing you expect to find in a cheap roof prism pair of binoculars so it would be difficult to complain here. In other categories the results are good or very good. Despite several slip-ups, after all endurance tests the binoculars still function correctly and can satisfy their user. I certainly didn’t expect that much in a case of a cheap device, mass-produced in China. A round of applause!