Recently, the Visionking 5×25 wide-angle binoculars came to my test. With a magnification of only 5x, he has a field of view of as much as 15.8 degrees. I looked at this binoculars for a long time, but everything was overcome by doubt. A binocular with such characteristics cannot also be inexpensive – there is always some catch, especially if it is a binocular with roof prisms. Well, it turned out that way, but more on that later. In the meantime, I propose to get acquainted with the miracle of the Chinese optical industry.
The binoculars come in a plain cardboard box with the manufacturer’s logo, as well as some features, in particular, “Fully Coated Optics”.
Aperture: 25 мм
Prism system: roof
Prism : BAK4
Focusing system: central
Field of view from 1000 meters: 277 m
Real field of view: 15.8
Exit pupil: 5 мм
Fog proof : Yes
Nitrogen filling: Yes
Eye relief: 15 mm
Coating : FMC green
Minimum focusing distance: 3 m
Net Weight: 590g
Includes a bag, shoulder strap, neck strap, lens caps, eyepiece caps, a manual and a cloth for wiping optics. The front gaps are held in place for a tripod.
The binoculars are quite weighty; the measured weight with covers is 560 grams. Ordinary 25 mm binoculars are much lighter and more compact – Visionking 5×25 is much closer to 8×32 binoculars. Close in parameters Veber 5×20 binoculars seem toyish. The case is rubberized with a metal chassis. It is comfortable enough in the hands, does not slip. A drum with a diameter of 29 mm, with a full rotation of almost 360 degrees, champs a bit and, when refocusing, sometimes the focus leaves the right eyepiece.
The optical scheme is unique to roof binoculars. Typically, in these binoculars, the lenses are stationary, focusing is carried out by moving the last primary lens (negative component). In the Visionking binoculars, the objective is two-lens, without a moving negative component – focusing is carried out by moving the entire lens unit. In fact, this is one binocular in the body of another binocular. To ensure the tightness of the binoculars, plane-parallel protective glasses with green coating with a diameter of 38.4 mm are installed in front. The measured working aperture of the lens was 25 mm, which is fully consistent with the declared.
The test with a flashlight showed that there are no antireflection coatings on the outer surface of the lenses and prisms, there is a green coating on the inside of the lens. The lack of coating negatively affects the light transmission, contrast, juiciness of the picture, glare. Sorry.
A huge leak of light into the prism was also detected from the lens side. Moreover, it is so large that it actually becomes the second exit pupil (see below). You can eliminate this leak with several homemade diaphragms-petals – this is shown below on the example of a finger. This should improve contrast.
Eye lenses are large, 24 mm, slightly concave. Coating is on both the external and internal components. The measured eye relief was about 13 mm from the glass surface. You can watch with glasses, if you snuggle hard, but the whole field will not be visible. The measured field of view of the eyepieces is 68.3 degrees. In this version of the binoculars the eyecups do not extend, however there is a similar version with the classic retractable eyecups. Diopter adjustment of the right eyepiece is carried out by rotating the entire eyecup. Some dust is visible in the left eyepiece.
The measured size of the exit pupil was 5.1 mm. Exit pupils are not round, a little “cropped”. In the upper area there is a huge false exit pupil – it was just visible from the side of the lenses. As mentioned above, a false pupil can be eliminated with a pair of apertures in front of the lenses. The measured magnification of the binoculars was exactly 5x for pictures without binoculars and through binoculars.
The clearance test showed low light transmission of the Visionking 5×25 binoculars. To the left, for comparison – Veber Prima 5×20 (declared transmittance of about 85%).
The test on ground objects showed that the image is visible through a haze and slightly darkened glass.
The sharpness of the axis is not bad.
The chromatism on the axis is invisible, it begins to mix with the field curvature.
The wide field of view of the binoculars in conjunction with a small magnification is impressive.
Collimation is good, eyes are not get tired of observations.
The field is not bad to the border between the center and the edge (50%), then strong curvature and astigmatism becomes noticeable.
The distortion is small.
Against bright light, the binoculars work disgustingly.
The star test showed that with a focused center, the star at the edge of the field of view is visible as a wand parallel to the edge of the diaphragm. When refocusing, it turns into a plus sign (+). The measured visual field of view by the distance between the stars was about 15 degrees. Comparison of the Visionking 5×25 binoculars with the Veber 5×20 binoculars showed a total defeat of Visionking in terms of brightness, contrast, image saturation. In fact, the image in 5×25 binoculars turned out to be MUCH dimmer than in 5×20 binoculars (with an approximate light transmission of about 85%). The image quality is approximately the same in a comparable field of view.
+ a large field of view
+ original design
Well, and probably the pluses ended there.
– lack of coating on a some surfaces
– plaque on prisms
-dust inside the eyepieces
– false exit pupils
– low image contrast
– poor sharpness at the edge of the field of view
– right focus the eyepiece “walks” when refocusing
– excess weight and dimensions for binoculars with such parameters
– terrible light transmission
– color distrosion.
Despite the shortcomings, I wanted to buy this binoculars. Just for the collection as a “chinese miracle of technology”, as well as a standard of how you do not need and at the same time do binoculars. However, I add that due to the large field of view, the binoculars were impressive when observing the landscapes. Do I recommend this binocular? No. In my opinion, its only use is daytime observation of landscapes. Of course, you can also look at the stars with him, but by the brightness of the picture he will lose to the similar Porro-binoculars with a smaller aperture. However, if the manufacturer makes this binocular better, at least having applied coating to all surfaces, covered the prisms with a good reflective coating, and even with phase correction, it would have turned out to be sweet. Let it affect the price, but it’s worth it.
When buying binoculars, I recommend writing to the seller so that he is sure to check the collimation of the binoculars before sending, as well as the absence of visible dust when viewing through binoculars.