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.
- 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.
- Is the image sharp enough?
Make sure that the lettering on a sign or the thin branches on trees are crystal clear. Also, make sure that the lights at night and the stars are not blurred and the shapes are not distorted. 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.
- Does it seem as though the colours are running together? How about discoloration?
When you look at a white object, a rainbow-type ring appears. Called chromatic aberration, the image quality usually decreases, and occurs with binoculars with larger apertures and higher magnification. Also, because of the coating and different lenses used for the binoculars, the colours may change. Point the binoculars at a white image and check to see how white the image is. In order to prevent discoloration, Canon has adopted the UD lens (15X50 IS AW, 18X50 IS AW, 10x32 IS, 12x32 IS and 14x32 IS) from the EF lens series, which is known for its superior optical technology. In addition, with the "super spectra" coating, we guarantee bright and clear images.
- Is the entire image clear?
There are more binoculars with a wide field of view to meet the demands of consumers. However, there are cases where the binoculars were "forced" to have a wider field of view, which causes the image quality around the edge of the lens to decrease. When this happens, most of the time it is caused by curvature of the field. Point the binoculars at a wall, focus on something simple, and check if you can see clearly all round. If the curvature of the field is large, the edges will be blurred. It is not recommended to purchase such binoculars. To greatly decrease the curvature of the field, Canon uses a field-flattener lens and an aspherical lens. With Canon binoculars, you will have beautiful image quality all round.
When looking through the binoculars, there are times when the perpendicular lines of windows of a building or bricks seem warped around the edge of the lens. This is called distortion. When the distortion is great, not only will the entire object seem distorted, but when you move the binoculars, it will seem as if the object were flowing, making it very hard to see. Canon uses high-precision aspherical lenses to correct the distortion.