Binoculars review

Steiner Cobra 10x42

Steiner Cobra 10x42
18 August 2014
The Cobra series of binoculars, produced by the German company Steiner, was launched in the middle of 2013. It consists of just two roof prism models: the 8x42 and the 10x42. These devices were categorized as hunting binoculars which is quite surprising because in that category Steiner has already the Ranger Xtreme series, with the 8x42 and the 10x42 models among others. The pricing might explain it a bit: the Rangers are about 200 Euro more expensive than their Cobra equivalents.

The producer boasts of applying special dynamic contrast coatings which increase the contrast during the observations in the forest, allowing you to spot animals against their habitat easier. The binoculars are completely waterproof up to a depth of 3 meters and nitrogen-filled; their working temperatures range from –20 to +80 degrees centigrade. The binoculars come with a 10-year guarantee of the producer.

  • Lornetka Steiner Cobra 10x42
  • Lornetka Steiner Cobra 10x42
  • Lornetka Steiner Cobra 10x42
  • Lornetka Steiner Cobra 10x42
Manufacturer data


web site

Distribution / Sales:

Kaliber sp. z .o.o.
web site

Magnification Lens diameter Angular field of view Prisms Eye relief Weight Price
10 42 100/1000(5.7o) BaK-4/roof ? mm 798 g 1495 PLN
Results of the review
Real front lens diameter Left:   42.18+/- 0.05 mm
Right:  42.2+/- 0.05 mm
8 / 8.0 pkt
Real magnification 10.19+/- 0.05x 3/3.0
Transmission 76.5+/- 1.5% 8/25.0
Chromatic aberration Low in the centre. A bit less than medium on the edge. 6.8/10.0
Astigmatism Slight. 8/10.0
Distortion The distance of the first curved line from the field centre compared to the field of view radius: 47% ± 2% 5/10.0
Coma Appears in a distance of 70% from the field centre and is a bit higher than medium on the very edge. 7/10.0
Blurring at the edge of the FOV The blur occurs in a distance of 69.5% ± 4% from the field of vision centre. 3/10.0
Darkening at the edge the FOV Noticeable but not especially bothersome. 3.8/5.0
Whiteness of the image Average. Over a dozen percent of difference between the red light transmission and the transmission for other colours. 2.8/5.0
Collimation Perfect. 5/5.0
Internal reflections
Left: Right:
Steiner Cobra 10x42 - Internal reflections - Left Steiner Cobra 10x42 - Internal reflections - Right
Noticeable false pupil, but, apart from that, quite dark.
Housing Very original and characteristic but also solid and handy. Comfortable to handle and to look through. The eyecups are rubberized, with 4-stop regulation; additionally they feature folded caps which are supposed to protect against the incidental light. The rubber near objectives doesn’t stick out at all. 8/8.0
Focusing Average size central wheel. Turns smoothly. Running through the whole range needs a turn through an angle of 550 degrees. Individual focusing on the left eyepiece – a big and comfortable ring which moves the rear element. 4.5/5.0
Tripod Averagely difficult to access 2.5/3.0
Interpupilary distance from 56.1 to 74.1mm 5/6.0
Closest focusing distance 1.60 m 2/2.0
Eyepieces FOV Apparent field of view of 58.4 deg (according to simple formula) and 54.0 deg (according to tangent formula). 9.5/20.0
Field of view Measured by us amounted to 5.73 ± 0.04 degrees and it was in full accordance with the specifications. A typical field for this class of equipment. 5/8.0
Quality of the interior of the barrels Black and quite well matted tubes, with nice baffles. Black bottom. Some specks of dust. 4/5.0
Left: Right:
Steiner Cobra 10x42 - Vignetting - Left Steiner Cobra 10x42 - Vignetting - Right
OL: 1.48%, OR: 5.34%
Prisms quality Good quality BaK-4. 8/8.0
Antireflection coatings Noticeably green on objectives, green-purple on eyepieces and green-yellow on prisms. Significant intensity. 4/5.0
Warranty [years] 10 4.5/6.0
Final result
124.4 / 190 pkt
Econo result 0pkt.


  • very solid and tough casing,
  • sensible correction of chromatic aberration,
  • slight astigmatism,
  • good coma correction,
  • appropriate blackening of the tube inside the binoculars,
  • high quality of prisms made of BaK-4 glass,
  • sharp image already from 1.6 metres.

  • too low transmission level in the centre of the visible spectrum and for blue colour,
  • weak image quality on the edge of the field of view,
  • noticeably truncated light exit pupil.

The Steiner Cobra 10x42 would be a very interesting option indeed if not for two serious flaws. The first one is, of course, its transmission – the appropriate graph we present below.

Its artificial limiting in the centre of the visible spectrum and the increase of its red part so brown animals are easier to trace and spot against the greenery of the forest doesn’t convince me at all. Personally I think the binoculars with a flat transmission graph on a level of 92-93% would perform much better, providing a more natural image.

The second problem is the sharpness of the image on the edge of the field of view. The binoculars don’t bowl you over with the size of that field. The best 10x42 class models can provide a field as wide as 6.5-6.8 degrees. The 5.7 degrees, the result of the Steiner, is perhaps not exactly bad because such a field is still comfortable to use, without creating an impression of looking through a narrow tunnel. However, such a limited field of view, especially if compared to the best models, should have been much flatter, with a better sharpness on the edge.

In other categories the binoculars get good or average results, without any serious slip-ups. Taking it into account and remembering its great ruggedness we admit the Steiner was very close to gain our recognition. Unfortunately the flaws we mentioned before force us to describe that product as just average. At that price point you can pick and choose among different rival pairs of binoculars which performances are similar or better.