Canon 10 x 30 IS Technology Guide - Page 12

Q7 How Can I Tell the Difference in Image Quality? The ideal binoculars are ones that make you forget you are looking through binoculars. If you purchase a pair with a wide field of view, and the image quality is superior (enough that there isn't much difference from looking with the naked eye), you will have many enjoyable hours of use. Some people have the misconception that because they only concentrate on the middle of the lens, even if the outer part is blurred, it really will not matter. Normally, the retina projects aberration-free images, so when you view blurred images, the brain tries to disregard them. If you consciously try to reject the blurred images for a long period of time, there is a chance that you will become very tired and even sick. It is very hard to determine the image quality with just a spec sheet. The easiest and surest way is to actually look through the binoculars. Please keep the following points in mind when purchasing binoculars. 1) Do you see only one image or two? Binoculars use two lenses parallel to each other. However, if alignment during manufacture is not perfect, or owing to shock during transport, the lenses may become just a bit off. If that happens, you will see two images. Even if you get the binoculars fixed, the lenses will tend to slip with just a slight jolt. Such binoculars are not recommended. 2) Is the image sharp enough? Make sure that the lettering on a sign or the thin branches on trees are crystal clear (See comparative photos "Resolving Power" on page 7). Also, make sure that the lights at night and the stars are not blurred and the shapes are not distorted (photo a). It may be difficult to know how clear the image is by looking through only one pair of binoculars. Try looking through several, and you will be able to tell the difference. 12