I'm about to be politically incorrect on several levels so be fair warned. Looks like Chaman has dropped some of his best poop and departed. Pity he didn't take cthahn and a couple others with him. tresap23, here's yesterday's version of this discussion in case you seriously "just can't put it down..." http://www.uglyhedgehog.com/t-452767-1.html. I don't care what anyone says, my old friend sharpshooter may have just shot his sharpest shot.

The biggest hole in Chaman's argument, which otherwise seems pretty sound if you happen to shoot like him and happen to agree with it, which I don't, is that if you tie yourself in a knot with no wiggle room, you'll just hang quicker. Often, we say "bif" like it's one word and means that everything we call "bif" is the same. Let me suggest to you the obvious - all birds fly at varying speeds over varying terrain and in varying light from each other and from themselves in certain situations. To presume that one knows exactly where to set shutter speed in all situations is not a good thing so setting a ridiculously high shutter speed to make sure you get the shot you want can make the difference in getting the shot or not. It obviously depends on what's important. I did note that he said, to paraphrase, when you need to use auto iso, do it. Of course, not doing so means that you may miss your shot and you may not know in advance that you're going to miss it. To presume that you will automatically get thousands more opportunities is also fraught with faulty logic. I can go weeks without seeing a bird where I am and have no vague notion where on this great big globe I might go to get a particular shot of a particular bird, how long I may have to stay there or where else I may have to go for that shot and, and I'm kinda a homebody partially because I have a big medicine box I'm tethered to, well, that and a slew of doctors, plus nice warm food and a soft pillow.

As is graphically suggested below, a lumbering Heron is no match for a Chickadee when it comes to speed and distance traveled and the difference is all but incalculable for an dumb ol' hobbyist like me who hasn't and isn't going to spend a single minute reading about sensors. "I buys my ticket and takes my chances." If Canon, Nikon, et al, can't figure out how a sensor works without me, they're in a bad place. Not normally a nitpicker, I have to say that different birds at different times in different situations present different challenges and nobody, repeat NOBODY, can calculate all the aspects of the exposure triangle and hope to come away with enough shots of a particular situation to make the effort really satisfying. A Heron may fly faster than a Chickadee but man alive, to scale they are at opposite extremes when it comes to what's required to get a shot of each as a bif. You can pan with a Heron but you often can't even see an in-flight Chickadee in its chosen cover environment through your viewfinder, let alone track one, change your settings on the fly, and come away with what you want which, of course, covers Shaman's exception of "when you need to." As sharpshooter said, to come in here and say "NEVER" about anything does all us poor ol' dumb hobbyists such a disservice, especially when your images posted for our viewing pleasure don't seem to show that you have really tested your theory in practice.

Whether the added shots below are quality shots or not is certainly debatable and I wouldn't insist either way. They're probably not some of my best shots but they are nonetheless pretty satisfying to me, a late arrival to shooting bif at 79. The Heron shot is fairly obvious, nice day, frontlit sun, steady background, predictable behavior, and no need to rush. I used a Sony a6000 with an adapter and a Canon 400mm f/5.6L plus a Canon 1.4x II. The Chickadee shot isn't so obvious. It was done under a thick leafy canopy on a bright thinly overcast day with a tree in the distant background, shooting north so no direct light but the light coming through the sparse Locust tree's leaves did offer something a little shy of a perfect background situation. The Chickadees were shot with a Sony a6000, adapted Canon EF70-200mm f/2.8L IS II. Not knowing how fast a shutter speed I needed to catch a fast moving little bird with jerky motions I set 1/4000 (max for the a6000), f/8 to get dof for either side of the birds, and auto iso with a max of 6400 set. I first hooked up a "lightning/motion detector/trigger and even with the sensor aimed at the bird flying in a perpendicular flight pattern with the camera aimed five feet after the sensor, the camera fired too late to catch the bird. The Chickadee shots were still underexposed at that and required that I adjust the Raw exposure and use Topaz DeNoise to calm them down some. I figure that short of catching a bullet piercing a water balloon or a plane hitting the sound barrier there's not much trickier than shooting a Chickadee and still the hit rate isn't good pulling everything out the a6000 had, burst at 11fps. You certainly aren't going to be adjusting any settings on the fly and there may not be all that many chances unless you want to keep coming back or you can "arrange" the situation.

Sorry - I've shown these shots a few times lately and I don't mean to be boring but they demonstrate several points in this discussion as they have in others. I'm not fishing for complimentary comments. What isn't realized by many in this, and other discussions in uhh similar to this, when all the technical stuff starts flying, many of us can be seen nursing a bad case of glazed over eyes, me included. Of course, "it takes all kinds" and is the nature of the beast in forums, but some of you guys who dig all the technical stuff and like bantering about it aren't really contributing that much that's useful to the novice's understanding of anything and it appears that you sure aren't contributing very much to each other's enlightenment when all you do is contradict and argue with each other.

That is not always true, this is closer to being correct for digital photographers:
"In photography, exposure is the amount of light per unit area (the image plane illuminance times
the exposure time) reaching a photographic film or electronic image sensor,
as determined by shutter speed, lens aperture and scene luminance."
http://en.wikipedia.org/wiki/Exposure_(photography)

Once you have chosen shutter and aperture, the only way to optimise exposure
is by modifying the scene luminance with stuff like ND filters or lights.

Lots of lovely advice here, and a great read for those of us who like to see pedants trying to win each other over, by sheer force of their (questionable) logic.

As one of the few people here who actually owns a 7D Mkii, my advice is simple. It's a fine piece of equipment, with a reason for every single function on that dial. After all, Canon stuck so much good stuff in that body, they wouldn't have also added something that wasn't useful, occasionally... The logic of economics would preclude such a step.

You have a camera easily capable of over 200,000 shutter movements... Go waste/practice/play with a few hundred of those, while adjusting the Auto ISO settings. Try and bracket each shot with another setting or two, and then compare them. I believe you may find a valid reason or two (based on your own experience and the feedback presented by other 7D Mkii users), to use that Auto ISO setting. It's also quite possible that you'll find, after this experiment, that those are fairly rare occasions.

Doesn't matter. What is important is that you asked a reasonable question, received some good advice, and then tried out some scenarios for yourself, and also discovered what works for you and why. Armed with this knowledge and actual experience, and hopefully a degree of confidence in your camera, the next time that special scenario arrives for you, you will be able to use the function most useful for the job.

Congratulations, you will be composing art, at the point that the shutter falls.