Binoculars review

Bushnell Discoverer 10x42

Bushnell Discoverer 10x42
1 July 2010
The Bushnell Discoverer is one of more expensive binoculars series of this American manufacturer. It consists of roof prism models with the following parameters: 7x42, 8x42 and 10x42.

In all these binoculars Bak-4 prisms PC-3 phase correction coated were used. Additionally, all air-to glass surfaces were covered by high quality antireflection coatings, including specially designed, efficient XTR coatings. The outer lenses were covered by special Rainguard® layers which allow to remove dampness and dirt more easily.

These binoculars are waterproof and nitrogen-filled; they come with a 30-year-long guarantee and a comfortable eye relief.

  • Lornetka Bushnell Discoverer 10x42
  • Lornetka Bushnell Discoverer 10x42
  • Lornetka Bushnell Discoverer 10x42
  • Lornetka Bushnell Discoverer 10x42
Manufacturer data


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Distribution / Sales:

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Magnification Lens diameter Angular field of view Prisms Eye relief Weight Price
10 42 114/1000(6.5o) BaK-4/roof 17 mm 800 g 2375 PLN
Results of the review
Real front lens diameter Left:   42.03+/- 0.05 mm
Right:  42.05+/- 0.05 mm
8 / 8.0 pkt
Real magnification 9.85+/- 0.15x 3/3.0
Transmission 87+/- 3% 14.5/25.0
Chromatic aberration Low in the centre, average at the edge. 6.9/10.0
Astigmatism Low. 7.5/10.0
Distortion The distance of the first curved line from the field centre compared to the field of view radius: 44% +\- 5% 4.5/10.0
Coma Medium. 4.8/10.0
Blurring at the edge of the FOV The blur occurs in the distance of 88% +\- 4% from the field of view centre. 7.5/10.0
Darkening at the edge the FOV Slight. 3.7/5.0
Whiteness of the image Minimal cream. 4/5.0
Collimation Exemplary. 5/5.0
Internal reflections
Left: Right:
Bushnell Discoverer 10x42 - Internal reflections - Left Bushnell Discoverer 10x42 - Internal reflections - Right
Low but with noticeable false pupil.
Housing Solid, with significant weight but compact and great to hold in your hand. Good quality rubber, regulated eyecups with too much grease. 7.5/8.0
Focusing Comfortable central screw (480 degrees) an individual focus joystick. Nothing moves outside. 4.8/5.0
Tripod Brak. 0/3.0
Interpupilary distance from 57 to 73mm 4/6.0
Closest focusing distance 2.35 m. 1.5/2.0
Eyepieces FOV Apparent field of view of 64.4 deg (according to simple formula) and 58.7 deg (according to tangent formula). 13/20.0
Field of view Measured by us amounted to 6.54 +\- 0.03 degrees and was a bit wider than in the specifications. Wide field of view for this equipment class. 7/8.0
Quality of the interior of the barrels Inner tubes and the bottom black and matt. Minimal specks of dust on the prisms. 4.4/5.0
Left: Right:
Bushnell Discoverer 10x42 - Vignetting - Left Bushnell Discoverer 10x42 - Vignetting - Right
Egg-shaped pupils.
OL: 1.2%, OR: 5.9%.
Prisms quality High quality BaK-4. 8/8.0
Antireflection coatings Orange-purple on the objectives. Purple on the prisms. Green-purple on the eyepieces. 5/5.0
Warranty [years] 30 years. 5/6.0
Final result
22nd place in the overall ranking of the 10x42 binoculars test.
137.2 / 190 pkt
Econo result 36th place in the econo ranking of the 10x42 binoculars test. -1.2pkt.


  • wide field of view,
  • very solid housing,
  • field of view sharp even at the edge,
  • low astigmatism,
  • slight chromatic aberration,
  • high quality of prisms and coatings,
  • good transmission,
  • correct blackening inside the inner tubes,
  • good warranty conditions.

  • egg-shaped pupils,
  • lack of tripod exit,
  • a bit too high distortion.

A next set of binoculars which, along with the Docter and Ecotone SR-4 creates a group of triplets, very similar when it comes to the look, parameters and test results. However, the Discoverer stands out against the others because of the best sharpness at the edge and the wide field of view - the device should be certainly praised for it. On the other hand, though, it also has the most truncated exit pupils which influence the amount of gathered light. It’s a pity – if the exit pupils had the right shape and if the device had a tripod exit, the Discoverer would be one of the hits of our test. Even with these flaws, the product is still worth recommending.

The price of that product might be another problem. In the USA it costs about 350 USD. You can legally import it to Poland buying it in an American shop online for about 1500 PLN, the costs of transport, duty and the VAT tax included. That amount is significantly lower than 2375 PLN – a price suggested by the Polish distributor. With the lower price tag it would be undoubtedly one of our favourites here.