This is pretty straight forward. If a bird is in open sky, you want as many focus points as you have to get that bird in focus.

If the bird is in branches, you don't want the camera to pick a branch, so you limit the focus points. Often to just one.

I choose the number of focus points based on the conditions. Basically, I don't want the camera choosing the focus point if there is a good chance it will choose wrong.

Basically, camera focus is a lot like Murphy's Law where if something can go wrong, it will. With focus points, if the camera can pick the wrong focus point, it will.

I understand this. When doing Wildlife, Birds in Flight with my Nikon Cameras, I tend to shoot with Group Autofocus. In Group AF there are 4 Focus points surrounding a Center AF point, you do not see the Center point but it is there. I also have MY Nikon Cameras set to Erratic on the Upper Selection which helps to tracking and on the Lower Selection I have it set to Quick Response which helps when You have a Bird flying in and out of Trees. Both features work great. As far as Sony goes, I sold it for what I paid and bought a Z9. The A1 was and is a great Camera, I used it to do a few Michigan Football games and Basketball which Sony excelled above my D5 and D500. With my D850 the difference was pretty much negligible. I really like my Z9 and it performed very well at Our U of M Spring game as well as my Birds in Flight plus Wildlife.

Example Images

Each example image, below provided as attached files in the replies below, shows the original crop from the camera, with a 1:1 crop of the details. The images all follow / demonstrate most (or all) 8 of the ideas above. The merged images have been resized to 2048px on the long side, but the 1:1 crop shows the actual details. The images are processed in Lightroom and the merged examples are created in PSE10 from the export files from LR. The square crops are 800x800 of the 1:1 processed details. You'll have to launch the attachment (or download) and zoom to the 100% zoom to see the same level of detail.

1. Panning Technique

The F-86 Sabre shown below was tracked with BBF until the plane reached the almost closed position when I then began capturing frames. The use of the 1.4x extender reduced the maximum aperture of this configuration to f/8. Experience has show the extended lens is a bit sharper around f/11. For the low(er) light on this cloudy day, I picked the slowest shutter I could use to free this fast moving subject (1/800) and balanced the ISO to the aperture. I captured probably 5 to 8 images as the plane passed, picking and keeping only the best of the group.

2. Focus Peeking

The Sony mirrorless a7II provides an invaluable tool for using manual focus lenses: the 10x focus peeking zoom in the Electronic View Finder (EVF). The manual focus / non electronic lens doesn't report the aperture to the camera. I'll guess this example was from an aperture around f/5.6. The shooting technique was to focus specifically on the blossoms and then shoot a burst of 3- to 5-images, allowing for any movement due to the slight breeze. Typically, I focus and shoot and then repeat by refocusing. Over the 10 to 20ish images that might result, usually there will be one if not several that are better focused than the rest. Again, I just find the best one and delete the rest.

3. Testing your lenses

The second of the two images below shows a technique for testing the 'corner sharpness' of your lenses. The first image of the security light shows an extract the 1:1 pixel level sharpness at an aperture between f/5.6 and f/8. The manual focus / non electronic lens doesn't report the aperture to the camera. I likely focused at the base of this multi-story bay window, in the foreground of the image. The extract of the security light shows some of the details of the image.

The second image shows a technique for 'testing the corner sharpness'. Note how the camera is held diagonally. You can do this for landscapes too, having the natural horizon pass through the frame's corner rather than the left- and right-sides of the frame. This technique then gives you 'details' in the corners to access the corner sharpness of the lens for each available aperture. Shoot the same image over and over after different apertures until you can confirm the sharpest results in the corners, when 'corner sharpness' is a desired result in your image. I know from experience this lens (FD 24mm f/1.4L) will need to be at f/11 or smaller to have the sharpest corners along with the point of focus. For this image, the corners are not relevant for this composition.

4. Single AF point on the animal's eye

I came away with probably 30 individual frames of this snowy egret. The bird moved slightly over about a 15-minute period as well as the sun / light changed slightly just before sunset. For Canon EOS bodies, using a single AF point will yields the sharpest results along all the other aspects of good shooting technique. I placed that single AF point the bird's eyes. The camera was in BBF. I would place the AF point, hold the BBF, release 2- to 3-frames. I rest my arms for a minute or two and then repeat the process, sometimes also moving the AF point by a position or two and / or change between landscape and portrait orientation to give composition options larger within the resulting images.

5. Single AF point on the statue's eye

Whether an animal or human or statue, a good composition technique is to always place the sharpest focus on the nearest eye of the subject. At f/2.2, the depth of field of this lens is rather narrow. The goal of the composition was to isolate this statue from the details of the background wall.

Thank you for this. I'm slowly working through all these ideas. I may start a new thread with my specific struggle.

I'm starting to think that I might just be expecting too much from my equipment (also some user error on the Nikon AF modes). In my last shoot I had over 3500 shots and my hit rate was under 20%. Most of those shots were not burst but roughly composed single shots so it was pretty painful to go through the raws. Thankfully I'm freelance and can submit however many shots I want so I appreciate this tutorial.

I know, Right? I believe that if we really sat down and thought about everything that we have today at our fingertips, we would surely scratch our heads and ask "How did they do yesterday what we look upon as something that we now take for granted? I believe that there exists true Artisans and True Engineers from yesterday that would surely put us in the backseat. With the "New Advents" in Photography they have made it so easy that a Monkey can do it. I enjoy the editing of Images that were once inconceivable of producing, to now making them appear as if they came SOOC. In a strange way I just do not appreciate the ways of some Photographers that take a shot and say "Well I do have 4-6 stops of making this a Photograph". In other words, I wish that it was more difficult to produce a acceptable Image, than one who pushes a "Slider" to show their work. I despise Lazy, yet I respect those who work to get all of the settings right to produce an Image that everyone likes. Digital has made people more dumb to the Basics of Photography. Let's really consider the process in which has had what I have stated. In the Film days, people had to beware of their Camera settings. Fast Forward to Today's World, they can rattle 40 exposures and hopefully one gets close. Digital has made Photography to not be so stringent on the basics. And, one day in the next 5-10 years, people will probably talking to their LR or Photoshop, directions on how they want the Photos to appear. It is unfortunate that we live in the "I want it now" World. Photographers do not exist anymore as they have learned through Computational ways to construct an Image. I know how to use The Adobe Creative Cloud to edit my images, but I do not want some Clown that does not know the first thing about Photography to be able to be a "So-called Creator".

Maybe so. But I just don't see us going back to the way it was. Topaz has opened the AI Pandora's Box. And we are only a couple years into this. Where does AI go next? I suspect that AI will be able to fix all the lens faults and make them seem like perfect lenses. Of course, the expensive lenses will still have the advantages of faster focus speed and wider apertures. But SW is going make most everything else a don't care. Eventually, they will be able to fix all the various lens distortions. And next after that, all that will be done in the camera.