It used to be that cameras had three or nine focus points, with maybe 30-50 on more top-level professional bodies. Nowadays, cameras have hundreds or even thousands of focus points with nearly limitless ways to combine and arrange them. One of the fundamental choices you will have to make is the size of your focus point, and this excellent video tutorial will help you decide which is right for your work.
Coming to you from David Bergman with Adorama TV, this great video tutorial discusses how to choose the proper focus point size for your work. This can be a tricky balance to achieve at times, especially depending on what you shoot. If you are tracking fast action, a larger focus point can be easier to keep on your subject, but on the other hand, a smaller focus point will make it more likely that you will get the focus exactly where you want it. This can be crucial if you are shooting something like a portrait with a shallow depth of field, where even focusing on the nose instead of the eye can throw the image wildly out of focus. Check out the video above for the full rundown from Bergman.
In the end it becomes interesting for me: The non-use of eye-AF because of the loss of control? I admit I have never used it. But I have heard this argument many times. Sports photographers don't use it because they are faster with their traditional methods and because they decide which subject is in focus and don't want the camera to switch to the next person because they were closer.
I grew up with manual lenses. Then there was autofocus with only one AF point and then a few around it. Focus and recompose, that was the way to do it. Later, I use Nikons, came 3D tracking and the ability to focus and recompose and then let the camera do the tracking of the fast moving objects. It seems to me that this is still the basic method today: focus and recompose when you don't have time to move the focus point in the viewfinder.
However, I have no doubt that mirrorless focusing on the sensor with the help of some clever algorithm is the future. And one day eye AF and tracking will surpass the traditional method. Just not yet.
What I discovered about focus and recompose was that shooting at or near wide open, DoF was razor thin. Recomposing required refocusing. Face/Eye detect + Servo AF practically automagically eliminates this for me. I utilize the two back button setup: one for Face/Eye detect, one for regular AF. I wish there was a way that once you lock on to a subject with regular AF, you could recompose keeping that same point where it was similar to how Face/Eye AF locks on as you recompose. The camera does offer a way to slide that AF point via the touch screen. But, the process would be faster via an algorithm. All these shortcuts just makes getting the shot faster and easier.
I think either Phase One or Hasselblad has that feature. It'll adjust the plane of focus when you focus and recompose.
Focusing and recomposing does not work if the subject is moving towards or away from you with the aperture relatively open. This is where Nikon's 3D tracking is useful (I don't know about other brands). The next step would be to focus and recompose with eye AF tracking or, as a backup, focus on the head or body when the eyes are no longer visible. I assume this already exists or will exist in the near future.
Face/eye detection + Servo AF works well when there is only one person present or the people are standing apart. But when things get crowded (like team sports or dance events), it will have troubles and might jump over to the wrong person. What's your experience with that?
Best focus point? Eye-AF, of course. j/k :)
When Eye-AF isn't working for the shot, I switch to small single point with eye/face AF turned off, this way it doesn't try to focus on the face, which at wide apertures, can totally miss the eyes. I have this saved on the dial memory position 2. The 1 position has the full blown wide area focus, eye and continuous AF. When using single point, by default I have the focus point at the upper 3rd of the frame since that's where the face typically is. If I focus-recompose, I don't have far to adjust and keeps the eyes sharp even at wide apertures.