Docter 8x42 ED
The binoculars come with standard parameters for instruments of this class: 8x42 and 10x42. Both devices are roof prism Schmidt-Pechan designs. According to the producer all air-to-glass surfaces were covered by high quality DOCTER®multitop antireflection coatings. The binoculars are also waterproof and nitrogen-filled.
| Magnification | Lens diameter | Angular field of view | Prisms | Eye relief | Weight | Price |
|---|---|---|---|---|---|---|
| 8 | 42 | 115/1000(6.6o) | BaK-4/Porro | 19.5 mm | 670 g | 3700 PLN |
| Real front lens diameter |
Left: 42.07+/-
0.05 mm Right: 42.05+/- 0.05 mm |
8 / 8.0 pkt | ||||
|---|---|---|---|---|---|---|
| Real magnification | 8.09+/- 0.1x | 3/3.0 | ||||
| Transmission | 85.8+/- 1.5% | 13/25.0 | ||||
| Chromatic aberration | Slight in the centre but still noticeable, low on the edge. | 7.3/10.0 | ||||
| Astigmatism | Corrected in a brilliant way. | 9.3/10.0 | ||||
| Distortion | Distance between the first curved line and the centre of the field compared to the field of view radius : 52% ± 3% | 6/10.0 | ||||
| Coma | Appears in about 75% of the field of vision and it is noticeably higher than medium on the very edge. | 6.8/10.0 | ||||
| Blurring at the edge of the FOV | The blur occurs in the distance of 87% +\- 3% from the field of vision centre. | 7/10.0 | ||||
| Darkening at the edge the FOV | Imperceptible. | 4.9/5.0 | ||||
| Whiteness of the image | The hole in the middle of the visible spectrum centre a bit smaller than in the 10x42 model but, overall, the whiteness rendering is good. | 4/5.0 | ||||
| Collimation | Perfect. | 5/5.0 | ||||
| Internal reflections |
|
3.3/5.0 | ||||
| Housing | A very handy, shapely and physically light instrument. Padded with black rubber armour of high quality. Comfortable to hold and to look through. The eyecups with four detention stops. The rubber sticks out a bit. Produced in Germany. | 7.7/8.0 | ||||
| Focusing | A huge and comfortable central wheel which turns through 540 degrees. It moves smoothly and is well-damped. Individual focusing on the right eyepiece, it moves the outer lens. A convenient ring. | 4.6/5.0 | ||||
| Tripod | There is an accessible exit but far from the binoculars’ centre of gravity. | 2.5/3.0 | ||||
| Interpupilary distance | from 55.6 to 74mm | 5/6.0 | ||||
| Closest focusing distance | 1.65 metres | 2/2.0 | ||||
| Eyepieces FOV | Apparent field of view of 51.7 deg (according to simple formula) and 48.6 deg (according to tangent formula). | 4/20.0 | ||||
| Field of view | Measured by us amounted to 6.39 +\- 0.04 degrees and it was a bit narrower than stated in the specifications. The field a bit too narrow for this class of equipment. | 4/8.0 | ||||
| Quality of the interior of the barrels | Inner tubes black but slightly shiny. Grey bottom. Very clean. | 4.2/5.0 | ||||
| Vignetting |
|
4.5/8.0 | ||||
| Prisms quality | Good quality BaK-4. | 8/8.0 | ||||
| Antireflection coatings | Greenish on objectives and prisms. Green-purple on eyepieces. Medium intensity. | 4.5/5.0 | ||||
| Warranty [years] | 30 | 5/6.0 | ||||
| Final result | 70.3% | 133.6 / 190 pkt | ||||
| Econo result | 0pkt. |
Summary
Pros:
- very nifty, relatively light and solid casing at the same time,
- sharp image in the majority of the field of view,
- exceptionally low astigmatism,
- slight coma,
- decently corrected distortion,
- negligible brightness loss on the edge of the field of view,
- correct blackening and cleanliness of the binoculars,
- good quality of prisms,
- exit pupils on a nice, dark background,
- long guarantee period.
Cons:
- narrow field of view,
- noticeably truncated exit pupils,
- significant transmission decrease in the centre of the visible spectrum.
 |
This test can be summarized in a similar way as the test of the 10x42 model. It is evident the designers of these binoculars focused on small dimensions and low weight of the equipment - the Docter looks very nifty and handy. Unfortunately it influences the dimensions of the prisms which make the exit pupils truncated.
In the case of the transmission, which graph is presented below, we can observe similar problems as in the case of the 10x42 model.
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A significant decrease of the transmission for green light, observed here, could be perhaps tolerated in the case of a ~200 Euro roof prism instrument but it befits ill the reputable Docter, with a price tag of almost 1000 Euro. At such a price point we would like to observe transmission values exceeding 90% in the whole visible spectrum.
 Bushnell Elite 8x42, Docter 8x42 ED and Nikon HG 8x42 DCF |
A worse result of the 8x42 model, compared to that of its 10x brother, stemms mainly from the field of view. In the case of the 10x42 equipment good quality eyepieces with an apparent field of view of 60 degrees were used. Here the producer was satisfied with less than 52 degrees so the binoculars boast a not exactly impressing field of view of 6.4 degrees. In the case of a good quality 8x42 model it would be good if the total field of view amounted to at least 7 degrees or more.
To keep the balance we must clearly state that we still deal here with a really good piece of equipment. A pair of binoculars which is able to get over 130 points in our tests cannot be a mediocre device. It is a pity, though, that buying such an interesting and not exactly cheap model, produced by a renowned German manufacturer, you still have to compromise. However if you decide to do so you get a handy, physically light instrument which corrects most of basic optical aberrations in an excellent way; it also comes with a long and reliable guarantee period.
