Telescopes with larger optical diameters collect more light, which leads to an increase in brightness and image resolution compared to smaller instruments. The difference between various types of fibreboards, such as HDF and MDF, is mainly the thickness, yet also how impact-resistant they are. Higher magnification bins tend to have a more distant minimum close focus than lower powered instrument. At IKEA we believe that sourced in responsible way, wood is a key change driver for climate mitigation.

The aluminium body feels really solid and well made and unlike quite a few other giant binoculars, these are fully water and fogproof, which not only protects them, but is also another indication of their build quality. What is more, there was absolutely no free play or movement in either eyepiece which was great and shows just how well they are made. Their very popular SkyMaster series is aimed at the more budget conscious user (for example see my review of the Celestron SkyMaster 25x70 Binoculars), whilst the Echelon series that are put together by hand in the USA using high end Japanese optics is focused more on quality: material quality, build quality and the image quality. Another quite important difference between these high end Celestron Echelon binoculars and the entry level Skymaster's is that the body on these has been fully sealed and they are described as being waterproof, whilst the Skymaster's are not. I would describe theses as having a really long eye-relief, making them an ideal choice should you wear glasses whilst using your binoculars.Coatings help maximize the amount of light transmitted through each glass surface of a binocular, so as much light as possible reaches the observer's eyes to provide a bright and sharp image.

The distance, measured in millimeters, between the observer's eye and the eyepiece lens in which the entire field of view remains visible. Registered Office of Faktum Ltd: Sweden House, 5 Upper Montagu Street, London W1H 2AG United Kingdom. All Echelon series bins, including this model use a individual focus system which essentially means that you need to focus each eyepiece individually by setting the diopter, which simply means turning the eyepiece.I have used a Celestron adapter in the past that came with the SkyMaster, which was ok, but because it plastic, it did have a tendency to twist a little under the increased weight of a giant binocular. If you happen to wear eyeglasses and wish to observe with them on, eye relief becomes very important. The large 70-mm objective lenses of these Echelon binoculars are treated with Celestron's proprietary XLT full multi-coatings for superior image quality, while the BaK-4 glass prisms deliver maximum light transmission. But where I really see them being ideal is for those who want them easy at hand or mounted on a tripod at a place where you have a great view of a distant hill or out to the ocean or lake and you like puffin, seal or whale watching or watching sailing or ships.

IPX-7 Water Protection: The International Electrotechnical Commision, or IEC, classifies and rates the degree of protection provided against the intrusion of water into a system that would suffer from damage were that to happen.The APM ED APO 10 x 50 binoculars is classed as offering IPX-7 protection, which means it will resist 30 min in up to 1m depth of water. Thereby they are also very suitable for an every day life in a kitchen with minor splash from the sink or moisture from the dishwasher.