The optical characteristics of lenses are composed of () factors.

The optical characteristics of lens refer to the physical properties formed by its optical structure, which are composed of three factors: focal length, field of view angle and relative aperture.

The optical characteristics of lens refer to the physical properties formed by its optical structure, which are composed of three factors: focal length, field of view angle and relative aperture. Any kind of optical lens can be distinguished by the technical parameters of these three optical characteristics. Focusing is the process of forming a clear image on the imaging device by adjusting the distance between lens groups. The depth of field is the area formed by those objects that can be seen clearly at the focus, which is called the depth of field. That is, when the lens is focused on the subject, the scenes before and after the subject can also be clearly imaged. This depth range is called depth of field.

Physical characteristics of light

1. In geometrical optics, light travels in a straight line. Both the straight "light beam" and the "light" of the sun illustrate this point.

2. In wave optics, light propagates in the form of waves. Light is like water waves on the water. Different wavelengths of light show different colors.

3. The speed of light is extremely fast. It is 3.0× 10 /s/s in vacuum, and the speed is slow in air. In the medium with large refractive index, such as water or glass, the propagation speed is slow.

4. In quantum optics, the energy of light is quantized, which constitutes the quantum (elementary particle) of light. We call it "light quantum" for short, so it can cause chemical changes of film emulsion and other substances.

Properties of light

Light can be regarded as a photon with certain energy and momentum. Its propagation mode can be regarded as a shear wave that vibrates periodically in the direction perpendicular to light. Due to the establishment of the concept of wave, terms such as wavelength, vibration frequency, vibration period, light speed, amplitude, phase, refraction, reflection, interference, polarization and so on have appeared accordingly.