The two thin hinges that span the barrels on the Carson RD 8x42 binocular look to be made from an some sort of metal ally, but most importantly they look and feel very robust and thus should keep the two barrels in perfect alignment, unless you were extremely rough on them! So whilst this is not ideal, for most users, I don't seeing it being more than a minor point that I needed to bring to your attention. Dielectrically treated prisms can have a reflectivity of more than 99%, which surpasses aluminium and silver treated ones by a long way. Coating Comparisons

These Carson binoculars use roof prisms made from BaK-4 glass to correct image gets inverted as it passes through the system. This is because many will boast that they are Fully Coated or Multi-Coated, however this only means that either all lens surfaces have been single coated or only some of the lens surfaces have been multi coated. Carson Optical sent me a couple of the models within the RD-Series to take a look at and so to start with, I decided to review the most popular 8x42 configuration. No information is given by Carson Optics as to the arrangement of the lenses within the eye-piece, so other than to say that I measured diameter to be 23mm diameter, which I have to highlight as being fairly large for a 42mm binocular: So whilst I could see a better and brighter image in my alpha, they were very close to the mid range benchmark in all but very low light conditions.This cookie, set by YouTube, registers a unique ID to store data on what videos from YouTube the user has seen.

This is is a few millimeters less than some, but I feel still offers the lenses and adequate amount of protection, keeping out of the way of light falling rain, dust and from being scratched when placing the instrument down on the barrel ends without the lens covers attached, which you shouldn't do anyway. Prisms So as you can clearly see with the comparison table below, these Carson binoculars do well within their price range,although it would have been even better if they could have managed to have added phase correction coatings to the prism which would just raise the image definition just that little bit more and take them up above the crowd in this price range. The Carson XM Series Binoculars also feature a rubberized armor coating and the body is nitrogen purged and O-ring sealed making them waterproof and fogproof. Most models have plenty of eye relief with twist down eyecups making them ideal for eyeglass wearers. The twist-up eye-cups on this instrument are about as comfortable as most others out there, so not too much to expand on here. The dimensions of the Carson RD-842, with the eye-cups twisted in and the hinge fully open is as you can see from the table above very regular for a 42mm binocular.

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Carson don't state the 'official' IPD range on these, but I measured it to be from a minimum of 5.8cm up to 7.7cm which is fairly typical for a 42mm roof prism binocular.

These three features as well as the low geared mechanism (takes just over two turns to go from Min. to Max. focal distance) means that I found it super easy to very accurately focus in on an object even when I tested them with gloves on. This can be an important point to keep in mind if you plan on going out in winter.The level of blurring right at the edge of the view was minimal and no more or less than what I would expect to find at this level. Considering that these do not have ED glass lenses which are supposed to reduce the aberrations that cause color fringing, I was impressed to see just how little fringing that I could see through this Carson binocular. The twist-up eye-cups turn just a little too easily for my liking. So whilst twisting them up is no problem, they do have a tendency to twist down again if you don't have them fully extended.