Binoculars review
Eschenbach sektor D compact 10x42 B
The Sektor D series of the German Eschenbach company consists of roof prism instruments with the following parameters: 8x32, 10x42 and 8x56. These are all-purpose binoculars - the smallest for tourists, the medium for ornithologists and daylight hunting, the biggest for astronomers and hunters.
The binoculars from this series are equipped with high quality BaK-4 glass in the Schmidt-Peschan prisms and all their air-to-glass surfaces are covered by antireflection multilayer coatings. Additionally, the binoculars are waterproof and nitrogen-filled.
| Magnification | Lens diameter | Angular field of view | Prisms | Eye relief | Weight | Price |
|---|---|---|---|---|---|---|
| 10x | 42mm | 105/1000(6o) | BaK-4/roof | ? mm | 820g | 1099PLN |
Results of the review
| Real front lens diameter |
Left: 41.75+/-
0.07mm Right: 41.83+/- 0.07mm |
7/8.0 | ||||
|---|---|---|---|---|---|---|
| Real magnification | 10+/- 0.2x | 3/3.0 | ||||
| Transmission | 91+/- 3% | 13/15.0 | ||||
| Chromatic aberration | Medium in the middle, high at the edge. | 4.2/10.0 | ||||
| Astigmatism | Slight. | 7.3/10.0 | ||||
| Distortion | The distance of the first curved line from the field centre compared to the field of vision radius: 37% +\- 3% | 3.5/10.0 | ||||
| Coma | Appears near 3/4 of the field of view but is low even at the very edge. | 8.3/10.0 | ||||
| Blurring at the edge of the FOV | The blur occurs in the distance of 80% +\- 2% from the field of view centre. | 5/10.0 | ||||
| Darkening at the edge the FOV | Noticeable but not very bothersome. | 3.5/5.0 | ||||
| Whiteness of the image | Light blue hue. | 3.8/5.0 | ||||
| Collimation | Perfect. | 5/5.0 | ||||
| Internal reflections |
|
2.7/5.0 | ||||
| Housing | Solid and compact. Nitrogen-filled and waterproof. Comfortable to hold and to look through. No shortcomings in fact. | 7.2/8.0 | ||||
| Focusing | Central is smooth, the screw is comfortable. Nothing bends under pressure, the eyepieces don’t move laterally. An uncomfortable and very difficult to move focus ring on the right eyepiece. | 4.3/5.0 | ||||
| Tripod | There is an exit with moderately difficult access. | 2.5/3.0 | ||||
| Interpupilary distance | from 58.9 to 73.9mm | 4/6.0 | ||||
| Closest focusing distance | 2.90 m. | 1/2.0 | ||||
| Eyepieces FOV | Apparent field of view of 60.2 degrees. | 7/10.0 | ||||
| Field of view | Measured by us amounted to 6.02 +\- 0.02 degrees and, within the margin of error, was in perfect accordance with that in the specifications. It could have been a tad bigger though. | 5/8.0 | ||||
| Quality of the interior of the barrels | Inner tubes and bottoms gray and moderately matt. Remains of glue and splinters obscuring the field of view. Single specks of dust on the prisms. | 3.2/5.0 | ||||
| Vignetting |
OP: 4.9% |
5/8.0 | ||||
| Prisms quality | Good quality BaK-4. | 8/8.0 | ||||
| Antireflection coatings | Greenish MC on all air-to-glass surfaces. Medium intensity. | 4.5/5.0 | ||||
| Warranty [years] | 5 | 3.5/6.0 | ||||
| Final result | 40th place in the overall ranking of the 10x42 binoculars test. | 121.5/170
71.5% |
||||
| Econo result | 18th place in the overall ranking of the 10x42 binoculars test. | 4.7pkt. |
Summary
Pros:
- good transmission,
- very low coma,
- slight astigmatism,
- solid, compact and handy casing,
- good quality of prisms which don’t cause any light fall-off near the edge of the field,
- good quality of antireflection coatings on all air-to-glass surfaces,
- good whiteness rendition.
Cons:
- very distinct chromatic aberration at the edge of the field,
- visible image deformations at the edge of the field,
- flares and false pupils,
- uncomfortable focus ring on the right eyepiece,
- it could have been darker and cleaner inside the inner barrels.
The assessment of this set of binoculars can be only positive. Its score was good, especially taking into account the price. The binoculars owes it to good optical properties because in the most important categories (coma, chromatic aberration in the centre, astigmatism, blur, transmission, light fall-off, whiteness) the results are on the average and very good borderline.
In this price segment slips-up are difficult to avoid. Here you can count among them significant chromatic aberration and noticeable distortion at the edge of the six-degree field. We also didn’t like the significant effort you have to put into focusing on the right eyepiece (what would happen in winter, with the temperature of ,say, –20 degrees C?) visible flares and false pupils and average blackening and cleanliness inside the inner tubes.
