I got the Eyeskey Infinity 8×50 binoculars for testing, which have very rare parameters (8 – magnification, 50 – objective lens diameter in millimeters). The official website claims Flat Field technology, where the manufacturer promises a sharp picture across the entire field:
There are no declared characteristics on the binoculars page. I found the company’s product catalog, there is some information there. In the fall of 2023, I had a chance to look through these binoculars at an exhibition – I liked them, I remembered their small dimensions and wide field of view.
The exit pupil is declared to be 6.3 mm, the field of view is 8.2 degrees, and the eye relief is 17.9 mm. Interesting.
EQUIPMENT
The binoculars are supplied in a cardboard box.
In the box:
-binoculars
-storage bag with logo
-bag strap
-neck strap 42 mm wide
-cloth for wiping optics
-lens caps (installed on the binoculars)
-double eyepiece cap (installed on the binoculars).
HOUSING, MECHANICS
The body is soft rubberized, pleasant to the touch. The binoculars are quite massive, 960 grams with covers. The length of the binoculars with covers is 146 mm, without covers 143 mm. The width of the binoculars is approximately 142 mm, the diameter of the tubes is 58 mm. There are two “ears” on the sides for a neck strap. On the side of the left half there is an inscription “Eyeskey Optics”. Under the bridge on the right half there is a serial number. Ergonomics, of course, are not like the “open bridge”, but it is quite convenient to use the binoculars.
The focusing wheel is 32.5 mm in diameter, rubberized, tight but smooth. Focusing to infinity is counterclockwise. The measured minimum focusing distance is approximately 150 cm. The measured range of the interpupillary distance is 55.6-77.6 mm, the shift of the halves of the binoculars is tight but smooth.
Diopter correction is achieved by turning the ribbed ring on the right eyepiece.
The eyecups are metal on the inside and rubber on the outside, diameter 45.7 mm. There are several positions with fixation (shift by 5.1 mm, 9.5 mm, 11.8 mm).
At the front of the binoculars, under a neat cap, there is a socket for a tripod adapter with a 1/4-inch thread.
OPTICS
The measured aperture is 49.5 mm. The objective lenses are recessed approximately 8 mm relative to the front edge of the binoculars. The objectives and prisms are fully coated, the highlights are green and yellow.
Eye lenses with a diameter of 23.42 mm, concave, green coating. The measured field of view is 59 degrees. The measured eye relief is about 17 mm. It is comfortable to look in glasses with screwed eyecups, the entire field of view is visible.
TEST
The light test showed that there is a distortion of color rendering (slight yellowness). Subjectively, during visual observations, this is not noticeable and there is no obvious yellowness, as with old Soviet binoculars.
By the test with a polarizing filter, the prisms have a phase-correcting coating.
The exit pupils are round. There is a small light leak on the side, but it is located outside the main exit pupil and does not interfere with observations.
The measured magnification is approximately 8.06x.
The binoculars have excellent collimation, and the eyes do not get tired at all during observations.
No channel desynchronization was detected, there are no delays when refocusing in either direction, and constant adjustment of the diopters in the right eyepiece is not required.
The image on the axis is sharp and contrasting. Longitudinal chromatic aberration on the axis is not noticeable. Lateral chromatic aberration is small. Despite the declared Flat Field technology, there is a noticeable curvature of the field, the image is noticeably blurred towards the edge. Straight lines are not curved. Due to the sufficiently large ocular field of view, immersion in the image is good. This is approximately how it is seen through binoculars during the day with the eyes:
With a larger exit pupil, blurring at the edges is more noticeable:
The star test showed that towards the edge of the field of view, when focusing on the center, a bright star is visible as a “parachute”, but when refocusing, it transforms into a “stick” directed towards the center.
SUMMARY
+ compact and with a large aperture
+ good mechanics
+ fully coated
+ comfortable eye relief
+ distortion corrected (straight lines do not bend)
– there is a field curvature
– some distortion of color rendition
I personally liked the Eyeskey Infinity 8×50 binoculars, I would not refuse one as a universal one (ground + astronomical observations). When viewing seascapes, I was captivated and could not tear myself away from the eyepieces. In the night sky, the binoculars also showed themselves well, despite the field curvature, but it would be better, of course, without it…