I want to know which lenses are available in SLR cameras, and what are the functions and functions of various lenses?

This question is really broad. Oh, hehe.

1. Ultra-wide-angle lens: A lens with a focal length less than 24mm is an ultra-wide-angle lens, and the viewing angle is larger than that of a general wide-angle lens, but the imaging will be barrel-shaped. For example, if you take a photo of a building complex, the roof of the building at the second end of the photo can be clearly seen twisting towards the center. This shot is often used to take pictures of scenery.

2. Wide-angle lens: The focal length of 24mm-50mm is wide-angle, and the focal length of this interval will be used to shoot environmental portraits in addition to shooting landscape themes (that is, portraits blend into the background, maintaining a sense of hierarchy but not blurring the background, thus generating visual impact). This kind of portrait photo taken with wide-angle lens is not easy to master, and composition is much more difficult than general shooting. Most photographers will appear unremarkable when shooting such films, while a few masters will shine brilliantly.

3. The standard lens with medium focal length: about 50mm- 100mm, the imaging of this focal length is between landscape and portrait, both of which can be shot, but they are not very good. Of course, the portrait taken with this fixed-focus lens does not count. This focal length is mostly used to shoot objects, still lives, etc., because the distortion of objects is small.

4. telephoto lens: 100mm-∞, with small and narrow viewing angle, but great depth of field. The longer the focal length, the more obvious the background blur. When the aperture reaches about 4, all the background almost disappears (at least you can't see what it is) except the focused object with a focal length of more than 300 mm. The focal length of 250mm under F2.8 aperture can do the above. This kind of lens is mostly used for portrait shooting within 200mm, removing the theme with strong background and shooting close-ups of people; A lens over 300mm is used to shoot sports games or celestial bodies.

5. Fisheye lens: the focal length is in the ultra-wide angle range, the lens glass protrudes from the mirror body, and the shooting angle reaches 180 or even 360. The image in this lens will have great distortion, which is useful for shooting scenery, and the curved horizon highlights great tension; Or take photos of business 360 for use.

6. Axis-shifting lens: Different from the ordinary lens, the axis of the ordinary lens is always perpendicular to the focal plane of the fuselage, and the axis-shifting lens can change this intersection angle according to different situations. Putting a wide-angle lens will cause distortion of the shooting scene, and the axis-shifting lens just removes this distorted lens. By manual adjustment, the real film will look the same as people do. Even if you shoot buildings, you will ensure that every building is completely perpendicular to the ground without distortion.

7. Macro lens: The focal length of all lenses is the closest, but generally more than 30cm, that is, less than 30cm, which will cause the lens to be out of focus. Macro lens is a lens with the nearest focal length within 3~5cm, which can almost focus on the subject; This kind of lens is characterized by detailed imaging, even a grain of dust will be reflected in the photo. At the same time, for example, use a macro lens with a focal length of about 100mm to shoot portraits, because this lens can produce a degree of blur that other lenses with the same focal length do not have, and macro lenses are mostly used to shoot flowers and insects.

There are about seven lens functions.

In addition, upstairs, it is almost divided into fixed focus and zoom lens.

Upstairs, it is added that the aperture of fixed-focus lens is generally larger than that of zoom lens. Fixed-focus lens has a simple internal structure and fewer lenses, so it will be better than zoom lens (of course, zoom lens of the same level).

The zoom lens is complicated internally, especially the internal zoom lens is more complicated, so the technology required to make the zoom lens into a large aperture is relatively high, so at present, the maximum zoom lens can reach F2.8, and the fixed focus lens can reach F 1.2.

The larger the zoom multiple of the zoom lens, the more convenient it will be to use and can be suitable for various requirements; However, the larger the zoom lens multiple, the more internal lenses, which will affect the imaging quality. You can't have it both ways!

Except for a few L lenses, zoom lenses with magnification greater than 3 times are all large zoom lenses at the expense of imaging quality, such as various sets of heads. This lens has no special lenses such as low scattering, aspheric surface and fluorite, and the imaging quality is greatly reduced. So when choosing a lens, don't choose a lens with a zoom factor greater than 3, except for the L level.

These are some of my feelings, hoping to help the landlord.

Generally, the focal length of 16-200 is used the most, and the focal length of 24-70 is the most. Therefore, 17-55, 24-70L or 17-50 is recommended for the on-hook lens, and 70-200 is recommended for the telephoto lens instead of 18-200.