The difference between full width and half width

The difference between a full angle and a half angle is that:

1, full amplitude has stronger signal-to-noise ratio quality. The signal-to-noise ratio (SNR) technology of sensor is one of the two important cores of digital imaging, and the other is the analog-to-digital conversion (A/D technology) technology of sensor, in which the number of pixels per inch is the key to affect the SNR, that is, the total number of pixels per unit area of sensor. Quan Huafu has lower pixels per inch, larger area of a single pixel, higher sensitivity of a single pixel, and less noise when the photoelectric signal of the sensor is converted, so the image quality is better. It is manifested in two aspects: first, the picture texture under low feeling is better; Second, the imaging ability under high sensitivity is better, and the latter is particularly prominent;

2. The lens has different perspectives. The imaging angle of the same lens is different with different sensor sizes. In digital photography, there is the concept of equivalent focal length (please go to Baidu separately and don't repeat it). When using lenses with the same focal length, the focal length coefficient of Quan Huafu is 1, and the focal length coefficient of half frame is 1.5 (Canon is 1.6). At the same shooting distance, Quan Huafu has a wider viewing angle and a half frame.

3. The depth of field effect is different. Because of the equivalent focal length, when shooting a picture with the same content, the shooting distance of half a frame is longer, which will lead to the change of depth of field (commonly known as blur ability). For example, for a lens with an aperture of F 1.8, the depth of field effect on the Quan Huafu fuselage is F 1.8, while the depth of field effect on the half-frame fuselage is F2.7 (the equivalent depth of field effect coefficient is approximately equal to the equivalent focal length coefficient, but it affects the luminous flux). Some lenses with so-called large aperture (the standard is F2.8 or above) can't actually achieve the effect of large aperture on a half-frame fuselage. The actual blur ability of the lens marked with F2.8 aperture is about equal to F 4.2 in a half frame.

4. The imaging quality caused by the lens focal length difference is different. Any lens has an optimal shooting distance (lenses with different focal lengths have different optimal shooting distances). At the best shooting distance (including the best aperture state, any lens also has the best aperture, and the SLR lens is usually at F5.6 or F8, but it is not absolute), the lens can reflect the highest resolution and the quality of the diffusion circle. Because of the equivalent focal length, the shooting distance of the same picture must be farther, except for the blur ability. That is to say, the farther away from the standard point of the best shooting distance (including farther distance and closer distance), the higher the decline of lens resolution.