Canon 7dmk2 AF Question

I thought Servo AF and iTR came together, but I was wrong. I've never had any 7D Mark II, but now I've updated my knowledge of this.

It turns out iTR is not at all a different focus method. It's a supplement to the AF point selection method, where you can set the camera to try to find a face/faces in the picture and use the AF point covering that face.
If you combine iTR with One Shot AF you get one face, focus on that and that's it. If you combine it with Servo AF, you'll continuously follow the face, as long as it's possible, with the camera's AF points.
iTR can work in conjunction with the larger AF point selection methods, zones and all points, so there is something to choose from.

The AF method called face+tracking, shown by Teamspeed below, where does it come from? Can't find it in the manual for neither the 7D Mark II nor the 5D Mark IV? Is it some other camera?

apersson850 wrote in post #19514676
They come together, of course. There will be no tracking unless you are in AI Servo mode, so of course they are related. You can augment Servo AF with iTR - that's probably the best way to describe it.

Face Detect/iTR is a completely different focus method and is independent from One Shot and AI Servo AF modes. It seems logical that once you engage that method, it auto employs AI Servo. I haven't used it in a long time due to its inaccuracies, but may try this evening.

It wouldn't make sense that the AF method says face/object TRACKING if it wasn't constantly keeping focus on an object, which is counter to One Shot, which implies zero tracking.

Wilt has a 7D2 (or did), so it is an easy thing to attempt on that, I don't have one any longer, but do have the 5D4, which has similar functionality.

snegron wrote in post #19511386
Is there a way to lock on to an AF point using just the shutter release button, or maybe with the AF ON button?

I know that the AF of the 7dmk2 is very different than the AF of my R6, but I'm wondering if there's a way to lock the AF on a specific target (like a subject's eye), then move/recompose while still keeping that point in focus no matter where it moves (like the R6 does)?

For example, lets say I'm taking a picture of my kid standing next to a large church in the background. My kid is positioned to the lower left side of the image, the church is behind my kid to the rear/right of the image.

With my R6 all I would do is focus on one of the eyes, slightly press on the shutter release button (or the AF ON button) and reposition my frame. The AF stays locked on my kid's face no matter where I move the camera as long as I'm slightly pressing the shutter release button. I want to do this with the 7dmk2.

Same would apply for sports. I'd like to lock on to one football player's face while he moves anywhere on my screen, regardless of how many other players are in the scene.

You are actually asking for two different things...

snegron wrote in post #19511386
... For example, lets say I'm taking a picture of my kid standing next to a large church in the background. My kid is positioned to the lower left side of the image, the church is behind my kid to the rear/right of the image...

This is a "focus and recompose" technique with stationary subjects.

snegron wrote in post #19511386
...Same would apply for sports. I'd like to lock on to one football player's face while he moves anywhere on my screen, regardless of how many other players are in the scene....

While this is face or eye detection and tracking.

There are ways to accomplish both with 7D Mark II, although some may not be as easy as with your R6.

For "focus and recompose", one way is to simply set the camera to One Shot focus mode. Optionally, turn on the Focus Confirmation beep if you wish. This only works in One Shot mode. This mode achieves focus, then "locks" for a short time, as long as you half-press the shutter release button. I am not certain how long the AF remains locked... I'm thinking about 15 seconds, but you should check the manual or confirm with some tests. However, you cannot use One Shot mode with moving subjects like in your second example. If the subject moves after One Shot has locked AF, the focus will be lost. (There's also a possible problem using One Shot with zooms, which I'll address below.)

Another method is to go into the menu to the Button Customization feature and change the shutter release from "AF" to "Meter". This removes autofocus from the shutter release button. Now only your thumb pressing the AF On button on the back will cause the AF to work. This is called Back Button Focusing and it allows you to start and stop AF whenever you like. So to focus and recompose as in your first example, all you do is achieve focus, then lift off the button so the focus remains set, recompose and take your shot without touching the AF On button again.

This second method... Back Button Focus... allows you to leave the camera set to AI Servo focus mode all the time. Normally you can't use this mode while doing focus and recompose technique because AI Servo never stops focusing, as long as the shutter button is half pressed. However, since you have changed that and now AF is only controlled by the AF On button, you can simply start and stop AI Servo any time you like. Many sports and wildlife shooters use BBF and AI Servo because you will be "ready for anything", simply by controlling the AF with your thumb. It takes a little practice, but soon becomes second nature (I've been using BBF for about 20 years).

Your second scenario, where you're trying to track a moving subject, is another matter and where AI Servo is essential. However, the 7DII cannot track the subject for you, the way the AF system of the newer mirrorless cameras can. It's up to you to maintain the AF point right where you want the camera and lens to focus. Maintain pressure on the AF On button to keep AF actively updating itself. Sorry, there's no getting around this with a DSLR (a couple models have limited subject recognition and tracking when using Live View mode... but the 7DII isn't one of them).

One reason for this is that while the 7DII has a lot of AF points (65), it is nowhere near as many as the mirrorless cameras. They have hundreds or even thousands of AF points covering most of the image area with virtually no spaces between them. The 7DII, on the other hand, has the AF points concentrated in that center oval and there are spaces between them.

I've shot sports for many years using BBF and AI Servo. When I'm in practice and shooting a familiar event, I rarely miss focus on more than 5% of my shots... sometimes even far less than that. It's not uncommon for me to take 1500, 2500 or more shots at an event. With events I know well, I rarely have more than one or two dozen missed. Those "misses" are usually my fault... not the camera or lens'. But it takes practice and some work to keep the AF right where you want it.

A side benefit of using BBF and AI Servo is that it will automatically "correct" the focus of many (most?) zoom lenses. A lot of today's zooms are "varifocal" designs. This means they don't maintain focus when the focal length is adjusted. Any time the lens is "zoomed", focus must be re-acquired. If you are using BBF and AI Servo that happens instantaneously. But if you are using One Shot (with or without BBF), you must remember to re-focus after any changes to the lens' focal length. You have to consciously lift off the shutter release and/or AF On button, then reapply pressure. It's much easier to just use BBF and leave the camera set to AI Servo all the time.

You might conduct some tests with any zooms you use, to see if they are varifocal or not (parfocal). Be sure to test them at close, middle and farther distances. For example, ALL Canon EF 70-200mm lenses are semi-varifocal. They maintain focus on more distant subjects, but will not maintain it when shooting closer to the lens' minimum focus distance. Parfocal zooms are much more complex, require more calibration and end up costing a lot more. ("Cine" zooms are often fully parfocal... but compare the cost of those! For example, a Canon EF 70-200mm f/4 will set you back $1499 and is close but not perfectly parfocal. In comparison a fully parfocal Canon CN-E 70-200mm T4.4 lens costs at least $5000!)

And the CN-E 70-200 mm lens doesn't fill the full sensor on a full frame still camera, since it's designed for Super 35 sensors.