Binoculars review

Bynolyt Hawk 10x42 BCF

Bynolyt Hawk 10x42 BCF
20 June 2010
The Dutch Technolyt company had been for many years the distributor of Fujinon, Miyauchi or Swift Optics binoculars in the tulip country. With the increasing access to the factories in China and Japan the company, like its Polish counterparts Ecotone or Delta Optical, decided to order binoculars abroad and sell them under their own, Bynolyt, brand name.

The offer is quite wide. The cheapest instruments are made in China, the more expensive ones - in Japan so the company’s strategy is aimed at tapping all price segments and we can find binoculars with the objective lenses’ diameters from 21 to 63 mm on its offer.

One of more interesting porro prism binoculars’ ranges is the Hawk series, including 8x42 and 10x42 models. Those stylish and solid instruments come from the medium price segment. Of course they are waterproof and nitrogen-filled and all air-to-glass surfaces are covered by antireflection multilayer coatings. The binoculars boast comfortable eye relief (18-19 mm) which allows observations even for people wearing glasses.

  • Lornetka Bynolyt Hawk 10x42 BCF
  • Lornetka Bynolyt Hawk 10x42 BCF
  • Lornetka Bynolyt Hawk 10x42 BCF
  • Lornetka Bynolyt Hawk 10x42 BCF
Manufacturer data


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Magnification Lens diameter Angular field of view Prisms Eye relief Weight Price
10 42 88/1000(5o) BaK-4/Porro 18 mm 715 g 1470 PLN
Results of the review
Real front lens diameter Left:   41.27+/- 0.05 mm
Right:  41.27+/- 0.06 mm
4 / 8.0 pkt
Real magnification 9.9+/- 0.2x 3/3.0
Transmission 92+/- 3% 19.5/25.0
Chromatic aberration Very low in the centre, a bit more distinct at the edge but also rather low. 7.2/10.0
Astigmatism Very nice, point-like images of the stars. Negligible astigmatism. 8.6/10.0
Distortion The distance of the first curved line from the field centre compared to the field of view radius: 61% +\- 8% 7/10.0
Coma It appears far from the center of FOV and is not high even at the edge. 7.7/10.0
Blurring at the edge of the FOV The blur occurs in the distance of 87% +\- 4% from the field of view centre. 7/10.0
Darkening at the edge the FOV Practically invisible. 4.7/5.0
Whiteness of the image Almost perfect. Really minimal yellow hue. 4.8/5.0
Collimation Exemplary. 5/5.0
Internal reflections
Left: Right:
Bynolyt Hawk 10x42 BCF - Internal reflections - Left Bynolyt Hawk 10x42 BCF - Internal reflections - Right
Housing Light and handy for porro binoculars. Comfortable to hold. Twisted up eyecups but with the tendency to extend at in-between positions. For some people they might be a tad too small. 7.2/8.0
Focusing Central screw with a click-stop mechanism as individual focusing of the left eyepiece. The screw has sharp projections so we can’t speak about a very comfortable work. The binoculars lack the classic ocular bridge so the focusing is smooth, even and the pressure applied on the eyepieces doesn’t cause any bends or shifts. With regard to that the work is exemplary. Running through the focus scale from infinity to close needs a 740-degree turn. 4.2/5.0
Tripod There is a comfortable exit. 3/3.0
Interpupilary distance from 55.6 to 72.5mm 3/6.0
Closest focusing distance 2.90 m. 1/2.0
Eyepieces FOV Apparent field of view of 51.3 deg (according to simple formula) and 48.0 deg (according to tangent formula). 4/20.0
Field of view Measured by us amounted to 5.15 +\- 0.04 degrees and was wider than stated in the specifications. A narrow field of view for this equipment class. 5/8.0
Quality of the interior of the barrels Dark and matt. Black glue near the prisms, gray bottom; screws and rails holding the prisms are matted; microscopic specks of dust inside. 4/5.0
Left: Right:
Bynolyt Hawk 10x42 BCF - Vignetting - Left Bynolyt Hawk 10x42 BCF - Vignetting - Right
OL: 0.5%, OR: 2.1%
Minimally truncated pupils.
Prisms quality Good quality BaK-4. 8/8.0
Antireflection coatings Greenish on the objectives and prisms, green-purple on the eyepieces. Flares intensity very low. 5/5.0
Warranty [years] 25 years 5/6.0
Final result
20th place in the overall ranking of the 10x42 binoculars test.
135.9 / 190 pkt
Econo result 6th place in the econo ranking of the 10x42 binoculars test. 8.8pkt.


  • very solid housing with a hidden ocular bridge,
  • good transmission,
  • negligible astigmatism,
  • low coma,
  • slight chromatic aberration,
  • well-controlled distortion,
  • sharp image in almost whole field of view,
  • excellent whiteness rendition,
  • good quality prisms,
  • practically unnoticeable light fall-off near the field border,
  • long guarantee.

  • narrow field of view,
  • inner flares-prone,
  • truncated pupils, not very welcome in this equipment class,
  • focusing screw could have had less sharp projections edges
  • the objective lenses are closer to 41 mm than to 42 mm.

The mere comparison of the number and significance of pros and cons, and one glance at the final score allow us to speak about this device mostly in superlatives. The product is really well-made although its excellent optical properties were achieved by narrowing the field of view. In the 10x42 class binoculars the 5.1 degrees field of view is a bit too small, especially that the competitors can have even the value of 6.5 degrees here. However, if the field of view is of no particular importance to you, the Bynolyt Hawk 10x42 will be undoubtedly an excellent choice.

At the end there’s just one question left to be answered: does the Bynolyt Hawk 10x42 and the Opticron HR WP 10x42 are exactly the same instruments? They almost for sure come from the same factory. They even look practically the same. One look at their parameters, though, reveals first differences – minimally different weight and eye relief value. It suggest a different eyepieces’ construction although their field of view remains the same. That hypothesis seems to be confirmed by the distortion and field edge blur measurements. Opticron focused on the very sharp field of view, practically up to the edge, but had to pay for it – the distortion is distinct. Bynolyt decided to compromise a bit in both cases. The next difference, very easy to spot, is a different hue of the objectives and eyepieces’ coatings although in both instruments they do an equally good job. The exit pupils also look different – they are truncated in various ways which might suggest a different fixing the prisms. The focusing works a bit differently too. In the Bynolyt it has the range from 2.90 meters to infinity. Opticron, taking care of ornithologists, moved the working range of the bridge so the binoculars have a minimal focus already from 2.7 meters; it might cause some potential problems with focusing for people with sight defects, though. The binoculars are not identical then, they differ in their constructions, the price and they have a different score in our test. We hope we made the choice a bit easier for you.