Learn photography from scratch [basics 13- do you really understand these shots (I)]

Refers to a lens whose focal length is close to the diagonal length of the camera frame. Cameras with different frames have different focal lengths of standard lenses. Although the standard lenses of different frames have different focal lengths, their vision is similar and close to that of human eyes. The standard lens is suitable for people's visual habits and easy to operate. In addition, his imaging quality is also very high.

Their focal length is shorter than the standard lens and their viewing angle is larger than the standard lens. 135 camera, with a focal length of about 30mm and a field of view of about 70 degrees, is called a wide-angle lens. With a focal length of about 22 mm and a viewing angle of about 90 degrees, it is called a super wide-angle lens. The characteristics of wide-angle lens and ultra-wide-angle lens mainly include

(1) large depth of field

(2) Wide viewing angle: it is beneficial to extract a wider range of scenery from close-range shooting, especially indoor shooting.

(3) The depth scene has a strong contraction ratio, which brings a strong sense of perspective.

(4) The image is distorted, especially at the edge of the picture. Close-range shooting should pay attention to the problem of image distortion.

Telephoto and ultra-telephoto lenses have longer focal lengths and smaller viewing angles than standard lenses. For a 135 camera, a telephoto lens with a focal length of about 200mm and a viewing angle of about 12 degrees, a focal length of over 300mm and a viewing angle of less than 8 degrees is called a telephoto lens, and its imaging features mainly include:

(1) The depth of field is small: it is beneficial to capture the image of the combination of reality and reality.

(2) Small field of vision: it can take a large image of the scene from a long distance, and it is not easy to interfere with the subject.

(3) It can reduce the depth ratio of near-big-far-small scenes, make the front and rear scenes compact on the screen, and compress the depth sense of the screen perspective.

(4) Image distortion is reduced, which is a common phenomenon in portrait photography.

The fisheye lens uses the distortion of the lens to obtain a large viewing angle, which is about 180 degrees, so it is named because its huge viewing angle is similar to that of the fisheye lens. The shooting range of fisheye lens is particularly large, which can greatly exaggerate the perspective effect of the scene.

(1) Circular image: also known as "round fisheye lens" and "all-weather language lens". Its viewing angle is greater than 180 degrees, and the maximum image field is smaller than the camera frame, so the horizontal viewing angle is equal to the vertical viewing angle, so the shot picture is round.

(2) Diagonal fisheye lens: The maximum image field is larger than the camera frame, and there will be no dark angle phenomenon, and the viewing angle is usually 180 degrees.

Reflective lens, also known as catadioptric lens, is actually a short and fat super telephoto lens, which is about half shorter than telephoto lens with the same focal length. The high light spot outside the depth of field of this lens often produces a unique circular light spot. Its disadvantage is that there is usually only one aperture, so it is not very convenient to control the depth of field, and it cannot be used for shutter priority automatic exposure.

On the lens, the fixed focal length is called fixed focal length lens, and the variable focal length is called zoom lens.

(1) Manual and automatic:

(2) Zoom range: From the zoom range, the basic types of zoom lenses are 17~35mm super wide-angle zoom lens, 35~70mm standard zoom lens, 70~2 10mm telephoto zoom lens and 200~400mm telephoto zoom lens.

(3) Zoom ratio: From the zoom ratio, there are 2 times, 3 times, 4 times, etc. regardless of manual or autofocus. The greater the zoom magnification, there are advantages that one lens can play several functions, but there are also disadvantages such as large volume line pair, relatively low image quality and relatively small aperture.

(4) Zoom mode: autofocus lens also has two zoom modes: automatic zoom and manual zoom. The so-called automatic zoom means that the camera will automatically expand and contract the lens to complete the zoom as long as the zoom button on the camera is gently pressed during operation. Manual zooming requires the photographer to rotate or push and pull the zoom ring of the lens to complete zooming.

Advantages: One zoom lens can replace several fixed-focus lenses.

Disadvantages: the aperture is usually small, which will lead to image shooting.

Tip: Equipped with a zoom lens. Recommendation: It is suitable to choose lenses with wide angle to medium telephoto, such as 24~ 135mm, 28~ 135mm, 28~200mm and 28~300mm. Among them, 28~ 135mm is the most ideal.