What is "hybrid AF", and how does it compare to other autofocus technologies?

Question

I've heard of some new cameras — particularly mirrorless cameras — with a feature called "hybrid autofocus".

What does this mean, and how does it relate to the traditional approaches of contrast and phase-detect automatic focus?

It seems to be generally touted as an advance (and linked to very fast focusing). What are the specific advantages, and are there any downsides?

Answer 1

Hybrid AutoFocus combines these two AutoFocus Technologies - Contrast and Phase Detection. In Hybrid initially Phase Detection is used, and then Contrast Detection is used. In Hybrid AF, Contrast and Phase Detection complements each other.

Phase Detection

• Advantage => Speed.
• Lacks => Accuracy.

The reason is, in Phase Detection the camera knows which direction to move to get the best focus. So it moves in that direction.

Contrast Detection

• Advantage => Accuracy.
• Lacks => Speed.

The contrast Mechanism, will get the sharpest focus. However, to know if this is the sharpest image, it has to shoot past the sharpest point, and then come back to the sharpest point. This is called as hunting.

Hybrid AF

• Advantage => Speed.
• Advantage => Accuracy.

In Hybrid AF it combines the autofocus. First it uses the Phase Detection to get to the closest possible AutoFocus Quickly. Then it uses contrast detection to fine tune to the best focus. That is why it is claimed to be superior to both.

For a video demo - https://www.youtube.com/watch?v=UfhKtwbqbfc