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Magnification	Lens diameter	Angular field of view	Prisms	Eye relief	Weight	Price
10	42	113/1000(6.5o)	BaK-4/roof	15.2 mm	710 g	790 PLN
Owners opinions: 0 Specifications

Real front lens diameter	Left:   42.2+/- 0.05 mm Right:  42.2+/- 0.05 mm	8 / 8.0 pkt
Real magnification	9.95+/- 0.05x	3/3.0
Transmission	85.8+/- 1%	13/25.0
Chromatic aberration	Low in the center, slightly higher than average at the edge.	6.1/10.0
Astigmatism	Low. A slight shimmering of stars at the center of the field.	7/10.0
Distortion	Distance of the first curved line from the field centre compared to the field of view radius: 42% ± 3%	4/10.0
Coma	Starts from a distance of about 70% of the field of view and is between medium and high on the very edge.	6.1/10.0
Blurring at the edge of the FOV	Blurr occurs in a distance of 69% ± 4% from the field of view centre.	3/10.0
Darkening at the edge the FOV	At medium level.	2.8/5.0
Whiteness of the image	A slight creamy-orange tint, at times leaning toward red. The transmission graph is relatively flat."	4/5.0
Collimation	Perfect.	5/5.0
Internal reflections	Left: Right: An interesting case, because in normal operation you can see small reflections behind the diaphragm, but shooting against a strong sun is really good and shows no major flare or artifacts.	3/5.0
Housing	Dimensions and weight are fairly typical for the 42 mm class. The actual weight is 687 grams, which is over 20 grams less than specified. It is covered with a fairly smooth rubber coating of an unusual shape. The rubber fits the binocular body very well, though it comes slightly loose near the objective lenses. It gives off a rather unpleasant smell. The rubberized eyecups feature three twist-up positions and a diameter of nearly 42 mm. They fit comfortably against the eyes. The binoculars are made in China.	7/8.0
Focusing	A sizable central focusing wheel with fine metal knurling, which operates smoothly and with just the right amount of resistance. Covering the entire focus range requires a full 810-degree turn - that’s quite a lot. Diopter adjustment is on the right eyepiece and moves the outer lens element.	4.5/5.0
Tripod	Quite comfortable access.	3/3.0
Interpupilary distance	from 55.7 to 73.8mm	4/6.0
Closest focusing distance	1.80 meters.	2/2.0
Eyepieces FOV	Eyepieces of apparent field of view of 64.1 deg (simplified formula) and 58.5 deg (tangent formula).	13/20.0
Field of view	Measured by us amounted to 6.44 +/- 0.04 deg and was slightly smaller than stated in official specifications. A quite wide field for this class of parameters.	7/8.0
Quality of the interior of the barrels	The inner barrels are dark gray and only slightly matte. There is no knurling, but there are several baffles. The base near the prisms is light gray. Quite clean overall, with literally just a few microscopic dust specks on the prisms.	3.7/5.0
Vignetting	Left: Right: OL: 4.91%, OR: 3.79%	3.5/8.0
Prisms quality	High quality BaK-4.	8/8.0
Antireflection coatings	Greenish-yellow on the objective lenses, greenish on the prisms, and greenish-yellow on the eyepieces. Medium intensity.	4.5/5.0
Warranty [years]	5	3.5/6.0
Final result	67.7%	128.7 / 190 pkt
Econo result		0pkt.

Summary

Pros:

• solid housing with an original design,
• good light transmission for this price class,
• reasonable color reproduction,
• properly corrected astigmatism,
• low chromatic aberration in the center of the field,
• no issues with coma,
• proper blackening and cleanliness inside the barrels,
• good quality coatings,
• high-grade BaK-4 glass prisms,
• very good value for money.

Cons:

• noticeable chromatic aberration at the edge of the field of view,
• image sharpness at the edge of the field leaves a bit to be desired,
• truncated exit pupils.

The Delta Forest 8x42 Gen3 recently tested by us raised our expectations regarding the performance of its 10x42 sibling. After all, one could expect similar performance, as both models share a common objective and prism design, differing mainly in their eyepieces. In addition, both instruments feature a very similar apparent field of view of about 65 degrees.

A glance at the front lenses, however, reveals a rather significant difference. In the 8x42 model, the coatings shimmered with a vivid green, whereas here the green is more muted and has a different shade. This suggests that the transmission curve might also be different. However, we do not have to rely solely on guesswork, as in this case we have a graph obtained using a spectrophotometer.

The tested binoculars do not show such a distinct transmission spike in the blue spectrum as the 8x42 model did. As a result, the Forest 10x42 achieves its best performance in red light, where transmission can reach a maximum of 89.6%. The second maximum, observed in the blue color range, is slightly lower, with its peak reaching 88.3%. Meanwhile, averaging across the center of the visible spectrum yields a result of nearly 86%, which is only slightly lower than that of the 8x42 model. In this price class, all these results are at least good.

The final score of the Forest 10x42 Gen3 is slightly lower than that of its lower-magnification sibling, but the difference is small and borders on measurement error across individual categories. In general, both of these binoculars are highly recommendable instruments characterized by an excellent price-to-performance ratio. If your upper budget limit is around 200 Euro, the third-generation Forests are very strong contenders. I recommend putting them to your eyes and checking whether their optical and mechanical properties suit your needs.

Delta Forest 10x42 ED Gen3, Focus Nordic Optimum 10x42 ED VHG ans Pentax SD 10x42 ED.