Classification and performance of lenses

Type and performance of lens 1 Ultra-wide-angle lens: A lens with a focal length less than 24mm is an ultra-wide-angle lens with a larger viewing angle than a general wide-angle lens, but there will be some barrel distortion in imaging. For example, if you take a photo of a building complex, you can clearly see that the roof of the building at the end of the photo is twisted towards the center, which is often used to shoot scenery. 2. Wide-angle lens: 24mm-50mm This focal plane is wide-angle. The focal length of this interval is not only used to shoot the landscape theme, but also used to shoot the environmental portrait (that is, the portrait blends into the background, retaining the layering but not blurring the background, thus creating a visual impact). This kind of portrait photo taken with wide-angle lens is not easy to master, and the composition is much more difficult than ordinary shooting. Most photographers will look unremarkable when shooting this film. The films of a few masters shine brilliantly. 3. Standard lens with medium focal length: about 50 mm-100mm-∞ This focal length is between landscape and portrait, both of which can be shot directly, but they are not very good. Of course, it does not include portraits shot with this focal length fixed-focus lens, which is mostly used to shoot goods, still lives and so on. 4. telephoto lens: 100. But there is a great depth of field, and the longer the focal length, the more obvious the background blur. When the aperture reaches about 4, except for the focused object with a focal length of more than 300mm, all the background almost disappears (at least you can't see clearly what it is), and the focal length of 250mm under the aperture of F2.8 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. 6. Shift-axis lens: Different from the ordinary lens, the axis of the ordinary lens is always vertical to the focal plane of the fuselage, and the shift-axis lens can change this intersection angle according to different situations, which will cause the distortion of the shooting scene. The shift-axis lens is to remove this distorted lens, and make the real film the same as the human eye through manual adjustment, even if shooting buildings, it will ensure that every building is completely vertical to the ground. No distortion 7. Macro lens: The focal length of the lens is the closest, but it is generally above 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 is not available in other equal focal lengths. Macro lenses are mostly used to shoot flowers, plants and insects. There are about the above seven lens functions, and the lens is also divided into fixed focus.