How to adjust the picture ratio of photographic SLR

When editing in image processing software, cutting means cutting according to the ratio of 1: 1, not stretching;

Some SLR cameras have a camera mode of 1: 1. Although this function is very small, some manufacturers distinguish different levels of cameras to widen the price gap on this issue.

In fact, it is easy to understand the picture editing software, 1: 1.