Mini Review of the Nikon “7x50 IF HP WP Tropical” binocular

By Rafael Chamón Cobos

Created: Oct.2006

Updated: Jan.2008

Updated: Feb.2010

Nikon 7x50 IF HP WP Tropical

It is a very nice porro binocular of classical marine style, black, leather finished and with individual focusing system. It is waterproof and filled with nitrogen. When holding it, it fits very well my hands. I feel it well balanced and it gives me a pleasant sensation of seizing (I do not have this pleasant sensation with rubber coated binoculars). Weight is 1,360g.

Mechanically it is outstanding. The axle and the eyepieces rotate smooth but firmly, not loose nor hard. Eyepieces settings range from +2 to -4 dioptries in steps of 0.5. Eyecups are made of rigid plastic and they are designed to easily rotate around the eyepieces, so avoiding an accidental dragging of the eyepieces themselves. These plastic eyecups are fully detachable from eyepieces (not of rolldown nor screwing type), allowing the use of spectacles when looking through the bino. But I do not recommend to detach them frequently. Two rubber accessories are included to be optionally mounted on the main plastic eyecups. They are intended to eliminate disturbing lateral light or rain on the eyes. For general use I find them annoying rather than helpful.

According to me, this model is optically excellent. The field of view is 7.3º, average in 7x50 binoculars. Sharpness is excellent in the middle of the field and very good near the edges, so I can swivel the eyes to reach the outer zones without appreciable loss of sharpness. In a comparison with my Carl Zeiss Jena Jenoptem 7x50W (that I will use as a reference), I realize that the Nikon is sharper, especially at the edges of the field. However, some chromatic aberration is visible in the outer zones since I see there yellow and violet colors at the edge of bright objects. For general use, in normal conditions I am not conscious of this amount of chromatic aberration, however it is there. Exit pupile is perfectly round and bright, and shows no light leakage in its sourrundings. Image contrast is very good. I could not appreciate ghost images nor flare when I tried to get them by looking at bright light sources and their sourrundings. However, this model is somewaht old and hasn’t got a multicoated anti-reflection treatment, being the reflections of lenses dark blue. In a comparison wiht the Zeiss, which is multicoated, I can hardly recognize a very slightly better contrast in the Zeiss. The overall transmitted color is neutral or slightly warm, same as the Zeiss. I cannot appreciate “kidney bean effect”. I mean that the field illumination does not change if I put my eyes slightly off the normal viewing position. However, it seems to me that the Zeiss is a little better in this respect: the illumination of the visual field is a little more stable. Eye relief is 15mm according to specifications, and I also measured this figure, being approximately 10mm from eye lens to the plane of eyecup’s rim and 5mm from this plane to the exit pupile. Generally speaking, the vision is comfortable. In respect to this, the rigid plastic eyecups are useful, because due to their great diameter of 43mm, they fully fit my eye sockets and the bino rests well on my face, so hand vibrations are reduced.

Bearing strap and case are very good. Case is rigid and robust, finished in artificial black leather, easy to open and close. It allows to allocate the bino without changing the interpupillary distance.

As summary I would say that this bino is a good competitor to Fujinon 7x50 FMT-SX or William Optics 7x50. In my oppinion its only weak point is that lenses are single coated, so the instrument has not the benefit of modern multicoating. I do not recommend it if you want to keep your spectacles when looking through it.

I paid 423 euros for it (new). This is about 540 US dollars. This price is between those of the mentioned Fujinon and William Optics binoculars, and is about the half of the price of the superior Nikon 7x50 Prostar (which is called 7x50 IF SP WP in Europe).

The differences between both Nikon models --Tropical and Prostar-- seem to be that in the Prostar lenses are multicoated and the field curvature is better corrected due to the use of an extra lens element placed just behind the prism cluster and just in front of the focal plane of the objective. See following photo taken out of an old Nikon prospect.

Besides this, dimensions and external appearance of both binos are the same (except that the Prostar shows a fine red line around the objectives). It would be interesting to evaluate the better performance of the Prostar against the price difference.

According to several users of 'Cloudy Nights' forum, chromatic aberration is similar in both models and the difference in general performance is very small, if any.

(End of the article)