William Optics 7x50 ED
WO 7x50 ED was equipped with huge prisms made of BaK-4 glass and a very solid casing. As a result this pair of binoculars is heavy and quite big. The instrument also features an individual focusing system.
| Magnification | Lens diameter | Angular field of view | Prisms | Eye relief | Weight | Price |
|---|---|---|---|---|---|---|
| 7 | 50 | 132/1000(7.5o) | BaK-4/Porro | 23 mm | 1600 g | 1299 PLN |
| Real front lens diameter |
Left: 50+/-
0.05 mm Right: 50+/- 0.05 mm |
8 / 8.0 pkt | ||||
|---|---|---|---|---|---|---|
| Real magnification | 6.85+/- 0.2x | 3/3.0 | ||||
| Transmission | 91.5+/- 4% | 19/25.0 | ||||
| Chromatic aberration | Low in the centre and medium at the edge. For ED glass it could have been lower. | 6.9/10.0 | ||||
| Astigmatism | Negligible. Almost point-like star images. | 8.4/10.0 | ||||
| Distortion | The distance of the first curved line from the field centre compared to the field of view radius: 58% +\- 3% | 6.5/10.0 | ||||
| Coma | Appears quite late, near ¾ of the field of vision, and is low on the edge. | 7.9/10.0 | ||||
| Blurring at the edge of the FOV | The blur occurs in the distance of 95% +\- 3% from the field of vision centre. | 9/10.0 | ||||
| Darkening at the edge the FOV | Negligible. | 4.7/5.0 | ||||
| Whiteness of the image | Very natural. | 4.3/5.0 | ||||
| Collimation | Perfect. | 5/5.0 | ||||
| Internal reflections |
|
3.7/5.0 | ||||
| Housing | Very solid and heavy. Comfortable to hold in big hands but certainly not an instrument for women. The eyecups are not especially comfortable and the rubber sticks out a bit. Objective caps fixed on thin straps. | 6.9/8.0 | ||||
| Focusing | Individual. Practically perfect. | 5/5.0 | ||||
| Tripod | There is a comfortable exit. | 3/3.0 | ||||
| Interpupilary distance | from 55.8 to 74.2mm | 5/6.0 | ||||
| Closest focusing distance | 4.2 meters which is a good result for Porro binoculars with an individual focusing system. | 1/2.0 | ||||
| Eyepieces FOV | Apparent field of view of 50.9 deg (according to simple formula) and 48.0 deg (according to tangent formula). | 4/20.0 | ||||
| Field of view | Measured by us amounted to 7.43 +\- 0.03 degrees and it was only by 0.07 degrees narrower than stated in the specifications. A quite wide field for such a class of equipment. | 6/8.0 | ||||
| Quality of the interior of the barrels | Inner tubes dark and mat from the inside. A bit of rust on the bottom and some white glue. Clean. | 3.9/5.0 | ||||
| Vignetting |
OR: 2.0% - elements in the pupil’s field . |
5/8.0 | ||||
| Prisms quality | High quality prisms BaK-4. | 8/8.0 | ||||
| Antireflection coatings | High quality coatings on all air- to-glass surfaces. Medium intensity. | 4.5/5.0 | ||||
| Warranty [years] | 1 | 1/6.0 | ||||
| Final result | 73.5% | 139.7 / 190 pkt | ||||
| Econo result | No econo rank in this test. | 0pkt. |
Summary
 |
Quite noticeable similarity to the Fujinon FMTR-SX 7x50 is indeed the first thing that sticks out. Outwardly these two pairs of binoculars differ only in colour and inscriptions on casings. Both instruments are heavy, big, equipped with huge Porro prisms and not less impressive eyepieces with individual focusing.
The mechanical workmanship is, by and large, perfect. The casing is made of strengthened aluminum with good quality rubber padding. Big eyepieces are comfortable to look through; it seems you can sit on the instrument and still it will be left unscathed. One thing you can carp about are these rubber objective caps, attached on thin straps – their life expectancy is not long. If you are not scared of significant dimensions and weight of the WO 7x50 ED you will take a liking to it for sure. Optics is definitely one of its more important strengths. Here in almost all categories the binoculars fared very well, even perfectly well. We deal here with negligible astigmatism, very low coma, very slight brightness loss near the edge of the field and low chromatic aberration. When it comes to the latter, we expected it to be even lower. ED glass obligates to a good performance, after all.
Noticeable central vignetting, on the level of 2%, can be called a minor slip-up – it can be seen when you look at exit pupils. An excellent image quality should be praised, though - good sharpness level, kept throughout the whole field of view, good control of geometric deformations and good whiteness rendering contribute to it.
What can be written in the summary? Perhaps that the best WO 7x50 ED recommendation is its final score. It shows unanimously that the lens, tested here by us, not only resembles Fujinons FMTR-SX outwardly but its optical and mechanical properties are similar as well. What’s the most important thing the WO 7x50 ED costs almost two times less than the Fujinons. I suppose that fact can replace the whole commentary.
