Talking about the main function of the shading ring
What is the main function of the shading ring? See the following introduction.
(一) Adjust and control the depth of field. This is an important role of the shading ring. Large aperture, small depth of field; small aperture, large depth of field.
(2) Affect the image quality. This is an easily overlooked function of the shading ring. Any lens has the best image quality with a certain aperture, that is, it is least affected by various aberrations. This aperture is commonly known as the best aperture. The exact position of the best aperture can be measured using a special instrument. Generally speaking, the best stop is located at the lens's maximum aperture reduced by about 2 to 3 stops. If the lens is larger or smaller than the optimal visor, the spherical aberration, longitudinal chromatic aberration, coma, curvature of field, and astigmatism of the lens will increase. Therefore, try to use the best aperture when shooting to improve the image quality. The shape of the iris aperture also affects the image quality. The closer the polygon is to a circle, the better the image quality.
(三) Adjust the light intensity. This is the basic function of the shading ring. When the light-shielding ring is adjusted larger, the incoming light intensity increases; when the light-shielding ring is adjusted smaller, the incoming light intensity decreases. It cooperates with the shutter speed to solve the exposure problem.