SLR camera lens: What are standard fixed focus and standard zoom? Wide-angle fixed focus and wide-angle zoom? . . . . .

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A standard lens refers to a lens with a focal length close to the human eye's visual angle, usually about 50 mm. For a 550D camera with APS-C format, this 50 mm refers to the equivalent focal length, that is, the physical focal length is about 30 mm. A standard zoom lens is a lens that gives consideration to both wide-angle and medium-long focal length within the standard focal length range. For example, 2470,24105 in Quan Huafu; 1855, 1750 in APS-C frame, etc.

A wide-angle lens is a lens whose viewing angle is larger than the focal length of the human eye. Generally, a lens below 35mm under Quan Huafu is called a wide-angle lens. Less than 24mm is also called super wide-angle lens. Wide-angle zoom lenses are lenses with a focal length mainly below 35mm, such as 1635 and1740 under Quan Huafu; 1022 in APS-C frame, etc.

A telephoto lens, also known as a medium telephoto lens, refers to a lens with a focal length greater than 50 mm, such as fixed focus, such as 85L, 135L and 200L under the rule of Quan Huafu; Zoom 70200, Quan Huafu 100400, etc.

Super telephoto lens is also called super telephoto lens. Quan Huafu usually refers to the focal length greater than 400 mm ... such as 500L, 600L, etc.

Macro lens refers to a lens with relatively high magnification. Usually, the magnification of the macro lens should be at least 1: 2, which means that the size of the object imaged on the negative can reach half of the real size. Most macro lenses can reach the macro of 1: 1, that is, the size of the object imaged on the negative is the same as the real thing. Because of the large magnification, the lens must be shot close to the object and the shooting distance is very close, so this kind of lens is also called macro lens.

Axis-shifting lens refers to a lens whose optical axis can be moved. In the optical principle, a lens can be simply regarded as a convex lens. The optical axis of the convex lens is constant, and parallel rays converge at one point. The shift lens is not. Through special design and use, the optical axis of the axis-shifting lens can be changed, so that non-parallel rays can also converge at one point, while parallel rays cannot converge. There are two main uses. One is architectural photography, which can change the proportional relationship of objects and make the perspective relationship of objects close to what people see. The second one can take some different photos through this special purpose, such as class model photos.

Magnifier can be simply regarded as a convex lens, which enlarges the photo through the optical principle of magnification to increase the focal length of the lens.

A catadioptric lens is a lens that achieves the effect of extending the focal length through the reflection of a mirror and the focusing of a lens group. This kind of lens is basically a super telephoto lens. Compared with the ordinary super telephoto lens, this structure is much simpler in design, much smaller in weight and volume, and much cheaper in price. However, due to the particularity of its optical principle, this kind of lens images in general, usually with only a small aperture.

I answered 900 words, all typed out one by one. Remember to add points, hehe.