免费a一级毛卡免费观看2020在线观看Whether you want to view the distant vistas or track elusive wildlife, there are hundreds of optics available, from爉icroscopes and rifle scopes爐o thermal and night visual aids. Understanding the different types of optics and their respective features is crucial when making a buying decision.
Shopping for binoculars燾an be quite confusing, as many come in similar-looking designs. You need to understand specs, such as magnification and objective lens diameter, to narrow down to the best one for your needs.
Full-size binoculars come with magnifications of 8 x 42 or 10 x 50. They capture more light and provide a wide field of view, making them ideal for wildlife viewing and boat use. Midsize binoculars usually have magnifications of 7 x 35 or 10 x 32. They strike a great balance between above-average light transmission and moderate size, making them an optimal choice for both sports and wildlife viewing. Common magnification specs of compact binoculars are 8 x 25 and 10 x 25. They're the smallest and lightest binoculars, thus the perfect choice when you're on the go. With?a href="https://www.jianfei80.com/c/buy/Monoculars/ci/1025/N/4083163871">monoculars, you get half a pair of binoculars, for viewing with a single eye, and they're more portable, compact, and lighter. What's more, if you have stronger eyesight in one eye, these could be more practical.
Since they come in a range of sizes and shapes, it's often daunting to shop for telescopes and astronomy爂ear. However, the most important specification of a telescope is the diameter of its light-gathering lenses, also known as the aperture. The aperture is usually expressed in millimeters or inches. For precise sky gazing, go for a telescope with at least 70mm (or 2.8 inches) aperture. Telescopes come in three broad categories: reflectors, refractors, and catadioptrics.
These use concave mirrors to gather and focus light. They have reliable apertures that offer sharp images with good contrast, for all kinds of celestial objects.
Refractors have the typical design of telescopes: a long tube with large lenses on the front and a smaller eyepiece on the back. The front lenses focus the light to form images, while the eyepiece acts as a magnifying glass that enlarges the images. Because of their large aperture, these telescopes are ideal for avid planetary observers.
With catadioptric telescopes, you get the best of both worlds. They employ both mirrors and lenses to form and enlarge images. Even better, you get a large aperture for precise star gazing, even with their compact size.
When shopping for rifle scopes and爏potting scopes, it's important to consider the magnification power. Some scopes have a fixed magnification of 20x, 25x, or 30x, while those with zoom eyepieces have variable magnification that's adjustable by hand within a set range, for instance, a 18x to 36x magnification.燗nother important factor to consider is the size of the objective lens. The larger the lens, the more the light transmitted to your eyes, which means brighter and clearer images.