Celestron 71454 Echelon 20x70 BaK-4 Prism Binoculars, Black

Product Information

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.

The `Visual Instruments` title at http://en.wikipedia.org/wiki/Exit_pupil for example, says exactly what I was trying to say, only in more detail. I didnt give wrong or misguided information! As you can see from the photographs, my preferred setup is to use what is known as a pistol grip tripod head that makes it far easier and faster to aim the bins as it works much more intuitively than a pan handle or standard ball and grip tripod head. I am currently using a Vanguard Pistol Grip Ball Head, which I really like but other photographic brands like Manfroto also make them if you are interested. High powered binoculars designed to excel in poor light or be used at night for Astronomy will always be larger than standard full size binoculars because they need much larger lenses to compensate for the high power and collect as much light as possible. Any binocular like these with objectives larger than 60mm is usually referred to as a "Giant Binocular". At 1650g / 59oz, they are as you can see from the table above a little more than double the weight of most standard sized bins. However they compare well to other giant binoculars and whilst they are heavier than the SkyMaster, remember that these have higher spec features like a full aluminium body, rather than a polycarbonate one that many cheaper bins will use. The eyepieces on this Celestron binocular feel really strong and whilst it is quite difficult to tell, it looks to me that the eyepiece housing is made from metal. This is excellent as this is the most common part of a bin that gets damaged or broken, yet to save costs many out there are made from plastic.Whilst I have already mentioned how well balanced the Celestron 20x70 Echelon binocular is and even with the high power and the fact that it is fairly heavy, it is still possible to use it very effectively with only your hands. However in some situations (like viewing up into the sky) or if you need to look through them for longer periods or if it is imperative that you have a very still image, you are going to want to attach this binocular to a tripod. The higher the magnification, relative to lens diameter, the dimmer the object will appear that you are viewing and the less you will ultimately see. If you are measuring a square or rectangle area, multiply length times width; Length x Width = Area. The way to calculate a rectangular area is by measuring the length and width of your area then multiplying those two numbers together to get the area in feet squared (ft 2). If you have on oddly shaped area, such as an L-shape, split it into square or rectanglualar sections and treat them as two separate areas. Calculate the area of each section then add them together for your total. If your measurements are in different units, say feet and inches, you can first convert those values to feet, then multiply them together to get the square footage of the area. Typically, a larger field of view is considered better, especially in situations where objects are moving (like some objects in the night sky).

If you are collecting timber products please collect at the time bookedi.e. 9am collection would be 9am > 9:45am, this helps us have the product ready for your slot and reduces customer congestion.So for example, all 20x70 binoculars like these produce a shaft of light that is 3.5mm wide (70 ÷ 20 = 3.5) - this shaft of light that exits the ocular lens in known as the exit-pupil. Not much to report here, other than to say that the colors look nice and natural and free of any artificial tinting that I sometimes witness, especially on cheaper optics. Higher magnification bins tend to have a more distant minimum close focus than lower powered instrument. Add to this the individual or fixed focus mechanism that requires them to have a really long depth of view and it is no wonder that they have a very far near focus of 328ft. As they are designed for long distance observation this should never really be a problem, but may be something to keep in mind for some. The 20×80 pair essentially provide more light into your eye and will ultimately enable you to see more (especially in dark conditions) Eye Relief

This tends to let me conclude that for a high powered bin like these, these are pretty good low light performers. Sure a super giant 20x100, would be even better, but you just try and hand hold one of those! No matter whether you are looking for something traditional, something modern or just something completely different, you will find exactly what you are looking for with Frames.co.uk. Also all the glass surfaces that the light bounces off within the porro prism reflect 100% of the light that hits them. This is also not the case with a roof prism and they once again require expensive highly reflective coatings to achieve the same transmission levels. The driver must have assistance to offload unless alternative arrangements made with our transport team

In good light they looked to be about equal, which once again, because my pupils were probably smaller than both the exit pupils, is not surprising. Whilst Celestron are best known for their telescopes, they also produce a number of standard daytime and astronomy binoculars. 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. With all that said about the quality of our picture framing services, you would expect our prices to be through the roof! All Binoculars if held aloft at arms length, looking at the sky/daylight, you will see a small circle of light exiting the eyepiece. That light is known as the Exit Pupil Size. If for example your Mothers eyes measure 5mm dilation at night, then a pair of 7x50 binoculars would give an exit pupil size of 50/7= 7.14mm of light `width` which exceeds the width of your Mothers eyes of 5mm, therefore wasting the light gathering power of the binoculars. Your 25x70 would give an exit pupil size of only 2.8mm. too little light maybe. By trying to match the exit pupil size of the ocular to the eye, you will get better light transmission into the eye, which gives as bright an image, that is possible with the optics in use. In the past I used to have some Helios `Stellar` 20x80. They were heavy, could have been better with a support of some kind (I used a wall?) but they only had an exit pupil size of 4mm and being of high magnification, reduces the field of view, So high maginication magnifies hand-shake, reduces the field of view, so you only see one star at a time instead of the whole constallation, and a darker view?

So, ’20×80′ binoculars give you 20 times the magnification of the object viewed by the naked eye, and achieves this with front lenses that are 80 millimeters in diameter. On some bins you get a large region around the edges of the view that is a little fuzzy. This amount of softening varies, with the best ones having almost none at all. I would say that whilst these are not the best I have ever seen, they sit near the top and the amount of softening that you can see is really not important and honestly only really noticeable if you are actually looking for it. Keeping in mind that my 10x42 benchmark has an exit pupil of 4.2mm (42 ÷ 10) and these have a 3.5mm (70 ÷ 20) exit pupil, it is not surprising that even though it was quite difficult to tell because of the large magnification difference, I did think that my benchmarks were brighter in low light, but the difference was not huge and you do of course get a much more detailed image with these Echelon's. on the other hand, will give you 25 times the magnification of the object viewed by the naked eye, and achieves this with front lenses that are 70 millimeters in diameter.Celestron also include a cleaning cloth, that is fine for emergency use out in the field of for cleaning the body with. But for regular and proper care of your lenses I highly recommend that you invest in a specialist optical cleaning kit. The 20x80s provide a higher eye relief than the 25x70s and are therefore more comfortable. Focus Type Also included are details of the lifetime warranty and what you need to do should they need any servicing or repairs. The Magnification is calculated in comparison to the naked eye (so 20/25x what your eyes can usually see).