Binoculars review

Olympus 8x42 EXPS I

Olympus 8x42 EXPS I
13 June 2012
The EXPS series consists of three Porro models with the following parameters: 8x42, 10x42 and 12x50. These instruments come with a solid, rubber-covered casing, equipped with BaK-4 prisms fully multi-coated. Additionally UV coatings were used which limit the transmission of harmful rays from that part of the spectrum.

Buyers get objective caps, a joined rainguard, a strap and a case. This pair of binoculars comes with a 25-year producer warranty period.

  • Lornetka Olympus 8x42 EXPS I
  • Lornetka Olympus 8x42 EXPS I
  • Lornetka Olympus 8x42 EXPS I
  • Lornetka Olympus 8x42 EXPS I
Manufacturer data


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Magnification Lens diameter Angular field of view Prisms Eye relief Weight Price
8 42 113.6/1000(6.5o) BaK-4/Porro 18.1 mm 780 g 539 PLN
Results of the review
Real front lens diameter Left:   41.95+/- 0.05 mm
Right:  41.92+/- 0.05 mm
8 / 8.0 pkt
Real magnification 8.69+/- 0.05x 2/3.0
Transmission 87.6+/- 1.5% 15/25.0
Chromatic aberration Not very high in the centre, negligible on the edge. 8/10.0
Astigmatism Stars are noticeably sparkling but still it is a medium level. 5.5/10.0
Distortion The distance of the first curved line from the field centre compared to the field of vision radius: 74% ± 4% 9/10.0
Coma Appears in the distance of 70% from the field of vision centre and is high on the edge. 6/10.0
Blurring at the edge of the FOV The blur occurs in the distance of 81% ± 4% from the field of vision centre. 6/10.0
Darkening at the edge the FOV Slight. 4.1/5.0
Whiteness of the image Good. A hole at 500 nm wavelength but later you have such a surplus of blue light that the overall effect (and white rendering) is flawless. 4.3/5.0
Collimation Perfect. 5/5.0
Internal reflections
Left: Right:
Olympus 8x42 EXPS I - Internal reflections - Left Olympus 8x42 EXPS I - Internal reflections - Right
Very high.
Housing Solid, classic Porro construction. Good quality rubber padding makes this instrument a joy to handle and to look through. Smooth regulation of eyecups. The rubber next to objectives comes off a bit. For such a price it would be difficult to have any objections. 7.7/8.0
Focusing A big, comfortable central wheel (280 degrees). It moves smoothly and is well-damped. A stable bridge – you can’t defocus the instrument just applying pressure on it. A bit of side play. A metal screw on the right eyepiece is just averagely comfortable; it moves the lens. 4/5.0
Tripod There is a comfortable exit. 3/3.0
Interpupilary distance from 58 to 72.1mm 3/6.0
Closest focusing distance 3.1 metres. 1/2.0
Eyepieces FOV Apparent field of view of 54.8 deg (according to simple formula) and 51.2 deg (according to tangent formula). 7/20.0
Field of view Measured by us amounted to 6.31 ± 0.04 degrees and it was a tad narrower than stated in the specifications. A small field for this class of equipment. 4/8.0
Quality of the interior of the barrels Black but slightly shiny inner tubes. Gray and a bit scratched bottom. The glue is sometimes black and sometimes white. Some specks of dust. 2.8/5.0
Left: Right:
Olympus 8x42 EXPS I - Vignetting - Left Olympus 8x42 EXPS I - Vignetting - Right
OL: 1.12%, OR: 1.63%
Prisms quality Good quality BaK-4. 8/8.0
Antireflection coatings Purple-green on objectives and eyepieces. Green on prisms. Medium intensity. 4.5/5.0
Warranty [years] 25 5/6.0
Final result
129.9 / 190 pkt
Econo result 0pkt.


  • solid, compact and stylish casing,
  • good transmission,
  • good whiteness rendering,
  • excellent correction of chromatic aberration,
  • very low distortion,
  • slight brightness loss on the edge of the field,
  • good quality of prisms and coatings,
  • long guarantee period.

  • narrow field of view,
  • definitely too light areas near exit pupils,
  • a bit too narrow maximum IPD,
  • inner tubes should have been blackened better.

The list of pros and cons looks exactly like that of the 10x42 model which was assessed during our big test of 10x42 class instruments. Also the final result in the test was similar – small wonder our summary will have the same overtone. Once again we would like to point out a very good price/quality ratio, offered by the Olympus - this pair of binoculars is relatively cheap but very well-made at the same time and with good optical properties. In fact many of its flaws are perfectly forgivable at this price point. One thing that we regret is the fact that it features such a narrow field of view. When you deal with binoculars having 10 times magnification ratio, you should expect a field of around 6.3 degrees. When it comes to the 8 x magnification (although the Olympus is closer to 9x than to 8x) a 7-degree wide field seems to be the bare minimum, especially when such competitors as the Nikon Action EX 8x40 can impress with a field reaching as much as 8.2 degrees.

It’s worth consulting also the transmission graph because it shows clearly what you gain when you use Porro devices which light loss on prisms is limited to the minimum.

The graph is perhaps not ideal but it leaves roof prism binoculars from the same price segment far behind. What’s more, only few roof prism instruments with a price tag two or three times higher than that of the Olympus can provide a comparable or better result. The maximum transmission reaching almost 95% is really a good achievement and if you add to that the surplus of blue light, where the transmission can get near 90%, you get a performance beyond reproach.

The transmission graph allows us to assess the effectiveness of UV coatings Olympus so boasts about – they are really efficient because the waves shorter than 400 nm are almost completely blocked off.

Olympus EXPS I 8x42 and Delta Optical Titanium 8x42

One glance at the photo above shows one more thing – the Olympus, being hardly among lightweight instruments, features a short, compact casing so it makes an impression of a handy and solid device. A long warranty period, given by a renowned manufacturer present on the marked for almost half a century, confirms that impression.

To sum up this pair of binoculars is highly recommendable providing that you don’t bother yourself with the narrow field of view of the Olympus and a bit overstated magnification.