What is the problem that autofocus is not as clear as manual focus? Is it out of focus?

1, autofocus adopts the principle of phase analysis, and there is an error every time.

2, manual focus 500D should be difficult to operate, there is no split screen, the viewfinder is very dark.

3. At a distance of 2 meters, autofocus uses the center point and focuses on one point. It's good to be right three times out of five.

4. The problem of out-of-focus is almost every shot, and the error is only the size. If the optical path length to the autofocus module is not equal to the optical path length to the negative, it is out of focus. However, manual focusing is also difficult to ensure that the length of the substrate in the optical path is equal to the length of the pentaprism split screen.

If you are very suspicious of the lens, you can borrow it.