What does aps-c cutting mean?

Aps-c cutting is a conversion cutting coefficient based on Quan Huafu.

The most intuitive explanation is that a lens with the same focal length will get different picture sizes on aps-c and Quan Huafu. aps-c with the same focal length is smaller than that in Quan Huafu, and the picture in Quan Huafu is wider. This size difference is the cutting factor.

The clipping factor is the ratio of the camera frame to the reference frame. Generally, this term applies to digital SLR cameras, and accordingly, 35mm Quan Huafu film is taken as the benchmark.

Cutting coefficient:

The purpose is to try to help photographers who use SLR cameras understand the performance of their existing lenses on emerging digital SLR cameras with sensor sizes less than 35mm. Taking the focal length multiple of 1.5 as an example, a photographer may say that a 50mm lens behaves like a lens with a focal length multiplied by 1.5 on his digital SLR.

What he means by this is that the camera gets the same angle of view as the 75mm lens on the film full-frame camera that photographers are more familiar with. Of course, the actual focal length of a photographic lens is determined by its optical structure and will not change with the sensor format placed behind the lens.

Most digital slrs (especially entry-level ones) on the market use the nominal APS-C sensor, which is smaller than the standard 24x36 mm (35mm) film frame. For example, the sensor size used by many consumer digital SLR cameras is 15x23 mm.

Therefore, the image data collected by the sensor is smaller than the 35mm frame area, which is equivalent to cutting off the corners of the 24x36 mm film Quan Huafu. Due to the above cutting, the effective viewing angle decreases proportionally from the smaller sensor size to the Quan Huafu (reference system).