GMGold Black Wooden Picture Frame, Wood, Lot de 1 NOIR, 10x15 cm

Product Information

At 8x Magnification: All binoculars with an 8x magnification and 25mm objective lenses have an Exit Pupil of 3.13 (25/8) and a Twilight Factor of 14.1, which if you compare them to a full size 8x42 binocular, which has an exit pupil of 5.25 and a twilight factor of 18.3, it shows that the increased objective lens diameter of the 8x42 binoculars will gather more light and make it possible for the binoculars to transmit more light to your eyes. This is the main compromise to using a compact over a larger pair of optics, but having said that in reasonably good lighting conditions like during the day, where your eye pupil size is only about 2 to 3mm, this will not be much of a factor, it is just at twilight and under poor light where you can really notice the difference. You must also remember that having a good pair of compacts even in poor light is still much better than having no binoculars at all! At 16x Magnification:When you increase their magnification to 16x their Exit Pupil reduces to 1.56 (25/16) which means that even less light will be getting to your eyes.

They have used BK-7 glass as the prism material. At this price point, BK-7 prisms are quite common, but due to them having a lower refractive index, they have a lower transmittance level and thus the image tends to be less bright and not quite as sharp around the edges as those that are made from BaK-4 glass which is generally the preferred option. Optical Coatings By opening and closing the central hinge, you can set the eyecups to match the distance between your eyes. On these, they go from a minimum of distance of 5.2cm apart, right up to 7.4cm.

inches to cm conversion chart

Save a few minor details like the variable magnification adjustment slider near the right eyepiece, the overall body shape of this Discovery Gator is very typical to that of your typical compact porro prism binocular, which is mostly a good thing as I find this particular shape comfortable to hold in the hands when using the instrument.

Comparing a low cost binocular like these with other binoculars that are far more expensive may seem a little unfair at first, but as long as you keep in mind the price difference, it does throw up a few interesting points and can highlight a few of their relative strengths and weaknesses and show where some of your money goes if you choose a more expensive pair of binoculars. Another downside to them not being fully covered in rubber is that there is more chance of them making a louder sound if something like your watch or more commonly a ring on your finger strikes against them. Rubber armour dampens down the sound and helps to ensure that you don't frighten away easily spooked animals like birds or deer. The binoculars fit comfortably inside and are easy to take out and replace, but without being so loose that they flop about which is good. As you would expect on a low cost compact, these don't come with a vast array of expensive coatings and things like super high quality extra-low dispersion glass, but because they are a porro prism binocular their prisms have total internal reflection and as such they do not need some of the coatings that roof prism's do to achieve the same quality of image. This is one of the main reasons why you often get a better performance from a low cost porro prism binocular than that of a roof prism one in the same price range.To see this in action, you can hold these binoculars up at arm's length and look at the eyepiece lenses, where you can clearly see the circle of light in the eyepieces, this represents the exit pupil. As you increase the magnification you can actually see this circle of light in each eyepiece getting smaller and smaller - see my series of photos below that I took to demonstrate this: At 20x power these are advertised as having an angle of view of 2.6° (45m @ 1000 meters / 135ft @ 1000 yards) which is very narrow and indeed it feels it when looking through them.

At 24x Magnification:When you increased to their maximum level of 24x the Exit Pupil reduces to just over 1 (25/24) which means that not a lot of light that enters the binocular will reach your eyes. Whilst not at the same level as which you get from a high or even mid-to-high level 42mm binocular for example, for a low costing 25mm compact binocular, I thought that the colors produced and the level of contrast you see in the image were pretty good. this is especially true at lower magnifications where I am happy to say they easily compare with the majority of other 8x or 10x compacts that I come across at this sort of price level. These are quite hard parameters to judge and very subjective, but I thought that the contrast of the image produced was good and once you have correctly focussed on an object the image is pin sharp. These EagleView Zooms come with a fairly disappointing 13mm of eye-relief, which may be something to keep in mind if you want to use your optics whilst wearing glasses. Ideally and to be sure that you have enough distance to play with to enable you to see the full field of view without any vignetting when using your glasses most experts recommend that you should look for binoculars that have an eye relief of about 16mm or more. In most cases an eye relief of 14 to 15mm is adequate for most people who wear eyeglasses to be comfortable, so 13mm is a little on the short side. Most non-eyeglass wearers will just use the eyecups in the fully extended position. I measured these to have a length of 10.4cm, a width of 10.2cm (with the hinge open) and a depth of 4.5cm (with the hinge open).

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You should be under no illusions - these are far from being the best binoculars in the world, but having said that these Nikon EagleView Zoom binoculars are far, far cheaper than the top of the range compacts and to be fair to them they are not at all bad and I would say easily outperform their price tag. If you can live with their weak points and are looking for a cheap pair of zoom binoculars then the Nikon EagleView Zoom 8-24x25 CF maybe just for you. Image shake dramatically increases at the higher magnification, which makes it very hard to view fine details, which in many ways can negate any advantage you get from viewing an object at a high magnification.