The indoor sports photographer typically faces one of the biggest challenges in the photography world.
Basketball, volleyball, soccer, gymnastics, wrestling ... The lighting at these events, at best, is usually dim. And spectrum-starved. The photographer is often confined to one location while the participants move around - a lot. And they usually don't move slowly.
An indoor sports lens needs to have a very wide aperture to enable a shutter speed fast enough to adequately stop the action. And yes, "adequate" in these situations often involves a compromise. A fixed focal length (or prime) lens is often a good choice as these lenses get the widest apertures.
Of course, the disadvantage of the fixed focal length lens is that you can't properly frame the fast-moving athlete as they go from near to far or far to near. The results from a prime lens in this scenario often require resolution-destructive cropping when the subject is too far away - or creative framing when the subject is too close.
When it comes to indoor sports, the biggest problem with zoom lenses is that they feature a max aperture no wider than f/2.8. And f/2.8 is usually what I consider the absolute minimum aperture opening for a successful indoor sports shoot.
In dimly lit arenas, even a max aperture of f/2.8 may require the use of ISO settings so high that an unacceptable amount of noise in your images is the result. Especially with an APS-C/1.6x FOVCF DSLR camera. I shoot indoor soccer in one venue where f/2 on a full frame body is not adequate.
You need to select the lens and position that works best for the particular situation - or carry a couple of cameras with different focal length lenses mounted.
Autofocus performance is a big differentiator between lenses when action sports are the subject. While most lenses can capture a distant subject running perpendicular from you across a court (a constant focus distance), it takes a good lens to be able to focus-track a fast-approaching or departing subject at close distances or with tight framing. Economy lenses will not typically be up to this challenge.
I will separate the recommended zoom lenses (first) from the primes (next). The lens models will be listed in focal length descending order.
The Best Canon Indoor Sports Zoom Lenses - My Recommendations
The Ultimate Indoor Action Sports Zoom Lens
The 70-200 f/2.8 L II IS Lens is arguably the best zoom lens available in any focal length range, but the 70-200mm range works well for many indoor sports purposes. This lens has very impressive image quality and very fast/accurate AF. It is very well-built and ready for the demands of professional use. This is my first choice for an indoor action zoom lens.
Pro-Quality Lens, Very Good Image Quality, Wide f/2.8 Aperture, Fast AF
If you can't afford the 70-200 f/2.8 L IS II, the 70-200 f/2.8 L is the next-best choice for an indoor sports lens in this focal length range. The IS II is a newer lens model with better image quality and image stabilization, but the non-IS lens performs very well in an indoor venue. It is a high quality lens.
Excellent Image Quality, Nicely Built, Wide f/2.8 Aperture, Great Autofocus Speed & Accuracy
For the closer action or the big picture, the 24-70 L II is an awesome choice. This lens can keep up with close/fast action and delivers image quality that is sure to please. It is a great choice for indoor sports photography.
Excellent Image Quality, Wide f/2.8 Aperture, Fast AF
This APS-C format-only lens will work well for close action or to capture the venue environment. This is not an L-lens, but the image quality it delivers is on par with those lenses bearing the red ring. Ring USM-driven AF is fast and accurate. Image stabilization, though not always helpful for photographing sports, is there when you need it.
The Best Canon Indoor Sports Prime Lenses - My Recommendations
Incredible Sports Lens
When your indoor needs call for the most focal length available, this is the lens to get. The price tag of this lens will set you back, but the image quality and performance it delivers will set your performance apart.
Also an Incredible Sports Lens
The 300 L IS II is every bit as good as the 400 L IS II in all regards, but in a wider focal length - one that I find myself using more frequently for indoor action. You can expect impressive images from this lens with have an equally-well-performing camera behind it - when you do your part correctly of course.
Ultimate Low Light Sports Lens
With the longest focal length available in an f/2 aperture, the 200 f/2 IS lens rocks indoor sports action. This lens will stop action in 1/2 as much light as an f/2.8 lens and will create a stronger background blur than a 200mm f/2.8 lens, better eliminating the distracting backgrounds common at indoor sports events. AF performance, image quality and build quality are as you dream they could be. As with Canon's other large, wide aperture primes, this is not an economy lens model - but it makes a great deal of economic sense for serious shooters.
Great Image Quality, L Lens Quality, Good Value
If is not an f/2 lens and it does not have a zoom focal length range, but the 200 f/2.8 L II has the price, size and weight advantage. This is a high quality lens that will get the job done vry well.
Wide f/2 Aperture, L Lens Build Quality & Performance, Good value
If the 200mm f/2 IS lens is out of your price range and you need/want the f/2 aperture, this is the lens to get. If you don't need a still-wider focal length of course - though you might want to make 135mm work just to be able to use this lens. The 135 f/2 L lens is nicely sized, focuses fast, has very nice image quality - and has a wide-as-it-gets-at-135mm f/2 aperture that will stop action and blur the background. And it has a good-for-what-you-get price.
Very Good Value, Fast AF, Wide Aperture
This 100 f/2 is not at the same level of elite-ness as the 135 f/2, but it is a really good value. For a very reasonable price, you get decent image quality, a wide f/2 aperture and Ring USM AF.
Very Good Value, Fast AF, Wide Aperture
The Canon 85 f/1.8 is practically an equal to the 100 f/2, including image quality and AF performance. The 85mm focal length is obviously slightly wider and the aperture is slightly wider. The 85 is also slightly less expensive.
Incredible f/1.2 Aperture, Great Build Quality, Excellent Image Quality
This lens is of a much higher grade than the smaller, lighter and far less expensive 85 f/1.8 - except in AF speed. The 85 f/1.2 L II is not slow, but it does not focus as fast as many of Canon's other Ring USM-driven lenses. And often focus speed is critical for indoor sports. So, you might want to rent this lens to see if it will keep up with your subjects before making a longer term investment. If it can keep up, this lens will deliver incredible images. The ultra-wide f/1.2 aperture will stop action in light levels that other lenses only dream of.
Sigma's Best Lens Ever?
I find fewer indoor sports events requiring wide angle lenses, but there are some. Such as shooting basketball from under the backboard. This is the best performing Sigma lens I've used as I write these recommendations. The ultra-wide f/1.4 aperture makes stopping low light action easy in normal venues.
Ultra-Wide Aperture, Excellent AF, Great Build Quality
While this lens is getting some age to it, it is still a good choice for most 35mm uses. You get Canon L lens build and performance qualities in a modestly wide angle focal length. This Sigma 35 f/1.4 is a sharper lens at wide open apertures, but it is hard to beat Canon's Ring USM AF system.
Ultra-Wide Aperture, Excellent Image Quality, Excellent AF, Excellent Build Quality
The 24mm focal length is going to be used primarily for close action, but is also wide enough to take in the big picture at an indoor event. There is no wider focal length lens available in an aperture wider than f/2.8 - 2 stops narrower than f/1.4. This is a great lens overall - including great image quality.
The list above is not an exhaustive list of lenses that can be used for indoor sports photography, but they are my top choices. Also visit the Canon Lenses page for other recommendations, including recommendations for Canon outdoor sports lenses.