Binoculars review

Alpen Optics Rainier HD ED 10x42

Alpen Optics Rainier HD ED 10x42
16 October 2011
The Rainier series consists of the best and the most expensive pairs of binoculars in the Alpen Optics line-up. Not so long ago it included the following models: 8x32, 10x32, 8x42 and 10x42, all of them featuring Schmidt-Pechan roof prisms made of BaK-4 glass which reflective surface was covered by 60 metallic SHR coatings; it was supposed to minimize the light loss to about 1%. Additionally these prisms are phase correction PXA coated. All air-to-glass surfaces are covered by multilayer UXA coatings which, added to the prisms coatings, are supposed to provide the transmission reaching 90%.

In 2011 the company decided to introduce some changes in the 42 mm class. The 8x42 and 10x42 binoculars gained a new casing and low-dispersion glass in objectives so a new mark - HD ED - appeared on their bodies. Rainier binoculars’ casings are made of magnesium alloys covered by high quality rubber which is supposed to ensure they are fully waterproof; the fact that the instrument is nitrogen-filled makes the elements also fogproof. The A-Lock dioptre locking system allows faster focusing and saving of the chosen parameters. Twisted-up eyecups feature detents. The pair of binoculars is offered in an elegant case, along with an additional leather carrying case and a comfortable, wide strap. Like all the models of Alpen Optics binoculars, also the Rainiers come with lifetime warranty period. The binoculars of this series are produced in Japan.

  • Lornetka Alpen Optics Rainier HD ED 10x42
  • Lornetka Alpen Optics Rainier HD ED 10x42
  • Lornetka Alpen Optics Rainier HD ED 10x42
  • Lornetka Alpen Optics Rainier HD ED 10x42
Manufacturer data


Alpen Optics
web site

Distribution / Sales:

web site

Magnification Lens diameter Angular field of view Prisms Eye relief Weight Price
10 42 114/1000(6.5o) BaK-4/roof 16 mm 835 g 3999 PLN
Results of the review
Real front lens diameter Left:   42+/- 0.05 mm
Right:  42+/- 0.05 mm
8 / 8.0 pkt
Real magnification 10.17+/- 0.05x 3/3.0
Transmission 86.4+/- 1.5% 14/25.0
Chromatic aberration Close to negligible in the centre of the field of view, medium on the edge. 7.5/10.0
Astigmatism Low. 8.5/10.0
Distortion The distance of the first curved line from the field centre compared to the field of view radius: 53% +/- 2% 6/10.0
Coma Appears near about 65% of the field and it is low on the very edge. 7.5/10.0
Blurring at the edge of the FOV The blur occurs in the distance of 80% +/- 5% from the field of view centre. 5.5/10.0
Darkening at the edge the FOV Almost imperceptible. 4.5/5.0
Whiteness of the image Quite flat graph in the range from 500 to 700 nm, with a noticeable hollow for blue colour. 4/5.0
Collimation Perfect. 5/5.0
Internal reflections
Left: Right:
Alpen Optics Rainier HD ED 10x42 - Internal reflections - Left Alpen Optics Rainier HD ED 10x42 - Internal reflections - Right
Very nice and dark area around exit pupils.
Housing Originally designed casing of the open-hinge type. Medium dimensions for this class of equipment. Very comfortable to hold and to look through. Rubberized eyecups with three detent levels. Makes the impression of a very solid instrument. The rubber next objectives sticks out very slightly. 7.8/8.0
Focusing Big, comfortable and ribbed central wheel with the working range of 580 degrees. Individual focusing through click-stop on the central wheel. Nothing moves outside. Perfection. 5/5.0
Tripod There is a comfortable tripod exit but located far from the centre of mass. 2/3.0
Interpupilary distance from 56.6 to 74.8mm 5/6.0
Closest focusing distance 1.6 m 2/2.0
Eyepieces FOV Apparent field of view of 65.2 deg (according to simple formula) and 59.3 deg (according to tangent formula). 14/20.0
Field of view Measured by us amounted to 6.41 +/- 0.04 degrees and it was a tad wider than stated in the specifications. A huge field of view for this class of equipment. 7/8.0
Quality of the interior of the barrels Dark but only partially matt. Slightly shiny walls of inner tubes. A little, gray bottom. A lot of specks of dust on focusing elements. 3.3/5.0
Left: Right:
Alpen Optics Rainier HD ED 10x42 - Vignetting - Left Alpen Optics Rainier HD ED 10x42 - Vignetting - Right
OL: 0.93%, OR: 1.10%
Prisms quality Good quality BaK-4. 8/8.0
Antireflection coatings Pink-orange on objectives, yellow-green-pink on eyepieces and pink on prisms. Low intensity. 5/5.0
Warranty [years] lifetime 6/6.0
Final result
149.9 / 190 pkt
Econo result 0pkt.


  • solid casing,
  • good transmission,
  • very low astigmatism,
  • slight coma,
  • quite well controlled distortion,
  • good whiteness rendering,
  • high quality of coatings and prisms,
  • low flares
  • imperceptible light fall-off on the edge of the field of view,
  • minimum focus already from 1.6 metres,
  • good warranty conditions.

  • noticeable chromatic aberration on the edge of the field of vision.

The best and the most expensive Alpen binoculars from the Rainier series gained our recognition during the 8x32 and 10x42 class binoculars’ tests where they were placed near the top of the ranking. Despite good performance the Alpen Optics company decided to give them a face lift and substituted 42 mm models by new pairs of binoculars, equipped with low-dispersion glass and a quite different outside design. It is against the rule which says that you don’t change horses in midstream, especially that just putting low-dispersion glass inside binoculars is not a remedy solving all problems; it can end up not as good as the producer has planned.

Fortunately for Alpen here everything went fine. The result of the new model is not particularly better than that of the old one but, taking into account the fact that it still remains excellent and the price stays at a roughly the same level (currently you can even buy it cheaper as it is being promoted), it would be difficult to carp about anything.

The transmission graph has changed slighly in comparison to the predecessor and now is slighlty worse with lower level of transmission for green-yellow and blue region of the visible spectrum. However, overall result in this category still remains good and we have no reason to complain here.

Despite using low-dispersion glass we couldn’t notice any significant improvement of the degree of chromatic aberration correction at the very ege of the field of view. If there is an improvement at all, it is slight. Fortunately the overall degree of that aberration is not high anyway and its correction in the center of the field is good.

Perhaps our summary is less than enthusiastic but only because we expected too much. When a company launches a successor of a very good model we count on it being a lot better and in many respects. Here you can’t see any noticeable improvement but, in order to keep the review well-balanced, we must state clearly that the result achieved by the tested instrument still remains splendid. If you add the fact that the successor weighs several dozen grams less and it doesn’t cost more than the older model, there is really no reason to complain because we deal here with a well-done, highly recommendable instrument.