Whoa, first off, congrats on the R1! That is an absolute beast of a camera and you are gonna love it for sports. Since you are heading to a soccer tournament in Chicago, you definitely need reach. Soccer fields are big and your kids will look like ants if you use a 24-70mm lens! I totally get the confusion with the numbers. Basically, the first numbers are your focal length (zoom) and the f-number is the aperture (how much light it lets in). For professional sports, you want a low f-number like f2.8 because it makes your subject pop and handles those cloudy Chicago days like a champ. Since you want one lens to stay on the body and you have a $3,500 budget, here is what i recommend based on my years shooting youth sports:

• Canon RF 70-200mm f/2.8L IS USM is the gold standard. It is super fast, incredibly sharp, and the f2.8 is amazing for getting that blurry background look everyone loves. You can usually find these for around $2,500 to $2,700, which leaves you plenty of cash for extra batteries or a fast memory card.
• If you feel like your kids are usually on the far side of the field, check out the Canon RF 100-500mm f/4.5-7.1L IS USM. It gives you way more zoom for those distant shots. It isnt f2.8, so it wont be as good in low light, but for outdoor day games, the extra reach is fantastic!
• Pro tip: Look for Refurbished or Open Box deals at big retailers. You can often save $300 on a basically new lens and stay way under your budget. I would go with the 70-200mm f2.8 tho. Its a legendary lens for a reason and fits the R1 like a glove.

I'm a bit late to this but i had a really rough time when i first started shooting soccer. I thought i could save some cash with a cheaper zoom, but honestly it was a total disaster. Every shot was blurry because i didn't understand the f-number thing... unfortunately i missed my sons first goal because the lens was just too slow to keep up with the action. I was so disappointed after spending all that money on the camera body. Basically that f2.8 number is what you're paying for. It lets in way more light so the camera can take pictures fast enough to freeze the running. I eventually gave up on the cheap stuff and got the Canon RF 70-200mm f/2.8L IS USM. It fits your budget and it is basically the only lens you'll need for those games. It really sucks to spend that much on one lens but trust me, i wasted more than that by buying the wrong things first. Just get the pro glass from the start and you wont have to deal with the headache of grainy photos or missed focus.

ngl i am super jealous, the r1 is a beast and you are gonna be so satisfied with the results. i have been using the rf system for a few years now and the way the lenses talk to the camera is just incredible for tracking kids running around. before you spend that $3500 though, i gotta ask a few things to narrow it down...

• are these games outdoors during the day or at night under stadium lights?
• how big are the fields usually? the lighting situation is huge for picking the right glass. tbh you should just stick with the canon brand. if you go with any of their professional zooms from the red-ring line, you really cant go wrong. just look for the white ones since they are basically the industry standard for soccer. they are built like tanks and the autofocus speed will blow your mind compared to a phone or a cheaper camera.

> i just want one professional zoom lens that stays on the camera so i dont have to swap things. Just catching up on this thread. Honestly, staying with one lens is the safest bet for reliability so you dont miss any shots while fumbling with a gear bag. I have been very satisfied with that simple setup for years and it works well for most field sports. Before you spend the money tho, are you usually allowed right on the sidelines or are you stuck further back in the bleachers? Also, are these games mostly during the day or are you dealing with those dim stadium lights in the evening? Knowing the light situation is huge for picking the right f-number.