How does a SLR camera take a picture of 16:9?

Mainstream SLR cameras, such as Nikon Canon, all have a picture ratio of 3:2, so they can't take photos with a ratio of 16:9. Sony doesn't know, but the default picture ratio must be 3:2. For a 4\3 system like Olympus, the picture ratio is basically around 4:3, and there is no 16:9.

Therefore, it is difficult to estimate the ratio of 16:9 directly on the SLR. If this ratio is really needed, it will have to be reduced later.