Features of telephoto lens

A telephoto lens refers to a photographic lens that is longer than the focal length of a standard lens. Long focal length lenses are divided into two types: ordinary telephoto lenses and super telephoto lenses. The focal length of an ordinary telephoto lens is close to that of a standard lens, while the focal length of a super telephoto lens is much larger than that of a standard lens. Take a 135 camera as an example. A photographic lens with a focal length ranging from 85 mm to 300 mm is a normal telephoto lens, and a lens above 300 mm is a super telephoto lens.

Long focal length lenses can be divided into general telephoto lenses, inverted telephoto lenses and reflective telephoto lenses according to their different optical group structures.

Refers to a photographic objective lens with a focal length longer than the standard size. In film photography, the horizontal angle of view is 23-24, and the corresponding focal length is about twice the diagonal length of the frame as the standard lens. The focal length of a 35mm film photography standard lens is equivalent to 50 mm, and anything longer than 50 mm is a long focal length lens; a 16 mm film photography standard lens has a focal length equivalent to 25 mm, and anything longer than 25 mm is a long focal length Lens. For feature film photography, a 75mm or 100mm long focal length objective lens is used to take close-up or large close-up shots. Because the camera is far away from the subject, it can avoid the actor's nervousness and facilitate lighting and lighting. A photographic objective lens with a particularly long focal length (such as 400, 800, 1000 mm or even longer) is called a "telescope lens", which can capture a certain detail of a distant object into a close-up lens, resulting in a screen effect of moving the distant object closer. However, the pictures taken by him lack a sense of space, depth and tou-view relationship. In science and education films, the telescope lens can be used to capture wild animals in a hidden distance to avoid disturbing the animals and make the picture appear natural and true.

The third is poor parallax. This lens has the characteristics of significantly compressing the depth of space and exaggerating the background.

The second is the short depth of field. Therefore, the subject in a chaotic environment can be highlighted. But it brings certain difficulties to precise focusing. If the focusing is slightly inaccurate during shooting, the subject will be blurred.

One is the small viewing angle. Therefore, the space range of the shot scene is also small. At the same shooting distance, the shot image is larger than the standard lens, which is suitable for shooting the details of distant scenes and shooting subjects that are not easily accessible.