1 ACCEPTED SOLUTION
" If you were going to upgrade from the Rebel XSI what would be the next logical jump?"
The next logical choice is the Canon 90D of course. 
The problem with most all the advice you got so far is these guys are just review readers. The same as you. Not many have actually "owned" and used both or all of them. I have or had the entire crop of 150-600mm super zooms. People tend to promote the lens they eventually bought as the best. Nobody wants to think they didn't buy the best.
The best of the crop right now is the Tamron SP 150-600mm f/5-6.3 Di VC USD G2 if you want the best IQ and AF ability. It also has a dock like most of the others. Which lens did I ultimately decide was the best for me? The Sigma 150-600mm f/5-6.3 DG OS HSM Sports Lens. It fits my needs and shooting style best. And, that is what you really need to decide, which one works best for you because all of them are good. The factor of money; cost it high on the list, too. The lens you wish you had won't take a better picture than the lens you have.
Something you haven't thought about and a couple lenses I am high on is the Canon EF 400mm f/5.6L USM Lens. Also, the Canon EF 300mm f/4L IS USM Lens along with the 1.4x tele-con. Yeah, they are primes, not super zooms but they work very well for what you want. A fixed aperture is nice. With the 300 +1.4x you get two FLs, 300mm and 420mm and a faster aperture. WHat's not to like?
Remember on a new 90D that would be (the 300mm + 1.4x) equivalent to nearly 700mm. Yes, I do own and use both of these choices too! BTW, it keeps all your gear all Canon.
" If you were going to upgrade from the Rebel XSI what would be the next logical jump?"
The next logical choice is the Canon 90D of course.
The problem with most all the advice you got so far is these guys are just review readers. The same as you. Not many have actually "owned" and used both or all of them. I have or had the entire crop of 150-600mm super zooms. People tend to promote the lens they eventually bought as the best. Nobody wants to think they didn't buy the best.
The best of the crop right now is the Tamron SP 150-600mm f/5-6.3 Di VC USD G2 if you want the best IQ and AF ability. It also has a dock like most of the others. Which lens did I ultimately decide was the best for me? The Sigma 150-600mm f/5-6.3 DG OS HSM Sports Lens. It fits my needs and shooting style best. And, that is what you really need to decide, which one works best for you because all of them are good. The factor of money; cost it high on the list, too. The lens you wish you had won't take a better picture than the lens you have.
Something you haven't thought about and a couple lenses I am high on is the Canon EF 400mm f/5.6L USM Lens. Also, the Canon EF 300mm f/4L IS USM Lens along with the 1.4x tele-con. Yeah, they are primes, not super zooms but they work very well for what you want. A fixed aperture is nice. With the 300 +1.4x you get two FLs, 300mm and 420mm and a faster aperture. WHat's not to like?
Remember on a new 90D that would be (the 300mm + 1.4x) equivalent to nearly 700mm. Yes, I do own and use both of these choices too! BTW, it keeps all your gear all Canon.
Ernie,
Thanks for the recommendation of the 120-300 2.8! I will definitely take a close look at it soon because that is a VERY versatile range.
I have been to a couple of private high school fields where the lighting is nearly equal to D1 university level lighting but most are very poorly illuminated even in the center 66% of the field with the end zones being far worse. For fields with good lighting or even for a lot of plays on poorly lit fields, a wide variety of glass and bodies will work well and I have seen some quite nice images captured by parents in the stands.
This first image from last Friday night was captured while there was still plenty of natural light and it didn't push the camera or lens capabilities but once full darkness fell the combination of fast glass and a great camera body are in their element where fast focus and decent noise performance at ISO 10,000 or higher in some cases are extremely helpful. I shot a lot of daylight soccer with the Canon 400 5.6 and 1D Mark 2 which did a great job as would many of the "slower" aperture high quality zooms on any decent DSLR but for fast action plays at a dimly lit football game I am sure I would find it extremely frustrating and would have to change my focus to different aspects of the game if shooting with a lens that is wide open at F5.6 or higher. Night soccer on a poorly lit field is the most challenging field sport I have photographed because the very fast and often unpredictable ball movement makes extremely fast AF under low light conditions critical and even the 1DX series don't do nearly as well with slow glass under these conditions. But if it were easy, there wouldn't be any real challenge or fun 🙂
I suspect those high school kids wisely chose to shoot subject matter and scenes that matched with the equipment they had available and wisdom goes further than technology. I have worked with a lot of yearbook kids over the years and working with these HS kids is a big part of the fun of high school sports. They are in large serious and very eager to improve their craft and you really can't ask for more. Just like the athletes they are rightfully proud of what they are accomplishing and they understand how to make the most out of a photographic opportunity unlike a lot of adults. I was in the CO Rockies a few years ago and several people were in a group trying to photograph bighorn sheep which were far too distant for their gear. A woman with this group spotted and got some great photos of a butterfly and some birds while her companions at best captured some poorly detailed and rather fuzzy images of distant large animals. She knew what she was doing.
And those high school kids were shooting with a lot better equipment than I did at their age because the technology has come so far in the past decades that a pretty basic consumer level DSLR can do things that a film SLR user woudn't have dreamed of when I was in high school. I suspect the ultimate future is full wideband capture of the visible light spectrum very much like military signal intercept does now with the radio frequency range where a very wide spectrum is continuously captured and then data analysis and DSP will choose what you want in perfect focus. At that point cameras and photographers as we know them now will be obsolete.
Rodger
