Chinese military 7x40 OBI0003 Binoculars

In summary, this binocular provides a reasonable performance. Its multi-coating appears to be of average quality. It does not reach the performance of the and is also somewhat behind the when coating and image brightness are considered. Its edge-sharpness is superior to both of them, but this is mostly a result of its narrower field of view. On the plus side there are a couple of excellent mechanical features. If the price of this binocular is reasonable, say below 150 US Dollars, it could well serve as a 'little man's IOR-SA'

The image is covering a conservative angle of 8 degs., yielding about 56 degs. apparent field of view. The brightness is moderate, with a slightly warm (yellowish) color tone. Sharpness is high in the central part and slowly degrading towards the edge, so that about 70% of the field (measured radially from the center) display point-like star images. There is some pincushion distortion visible, the panning is very smooth, making it an excellent binocular for surveillance applications. Under situations which are notoriously causing stray light, such like one hour after sunset, there is low-to-moderate response visible. The image then shows a diffuse white-out around the edge of field, that is not affecting contrast in the central region. In fact, the internal tube finish is somewhat glossy, and there is one side pupil visible, indicating a prism leakage. The latter is of less relevance, however, since with its large exit pupils there is little danger for the eye to catch stray light from these leaks. This glass is showing some ghosting when bright light sources are observed in the night, but the intensity of these ghosts remains moderate. The reticle on the right hand side produces a notorious reflex when the moon is observed. The low light performance is reasonable because of its large sized exit pupils, although the light transmission of this device is less than perfect.

The specification of 7x40 is the classical size for East Block military binoculars, see for example these . The sketch displays an air-spaced doublet objective and an ocular construction using five lens elements in three groups. According to the manual, this binocular is immersible in 1.5m deep water for one hour and operational from -43 to +55 degs. Celsius. The mechanics feels fine, everything is moving smoothly and without play. The eye-relief is generous, but the eye-lens is quite a bit recessed so that the effective distance is much lower than specified. It should still be enough to be used by eye-glass wearer, however, once the soft rubber eye-cups are folded down. The design reminds on the Zeiss Jena Septarem, i.e. the civilian version of the 7x40 NVA DF (without rubber armor), but it is less heavy and apparently has smaller prisms. It is resting comfortably and steadily during hand-held observations.

OBI0003