Indoor sports can be a nightmare to shoot. Most of the time, the gyms have poor lighting that causes havoc with your camera, resulting in dark, blurry images. However, I have some tips that will help you achieve good, quality results.
1. Shoot "Fast Glass".
If you can, shoot with "fast glass". Most consumers have a "crop" sensor camera. If you don't know what a crop sensor camera is, the chance that your camera is just that, is very high. In a nutshell, a crop sensor is a smaller sensor than the 35 mm full-frame sensor. In the film days, as slide of film was 35 mm. Most professional cameras have a 35 mm digital sensor. A cropped sensor is simply a smaller, more affordable sensor. The problem with a cropped sensor is that the sensor can catch less light than a larger one. Since gym lighting is often times poor, you need as much light to hit the sensor as possible. As the sensor is smaller on a cropped sensor, that means we need to use lenses that are "fast". If you can use a lens with an aperture of 2.8, or less (such as 1.8, 1.4, or even 1.2), it will allow so much more light onto the sensor. As these lenses are fast, they are also expensive. However, you can achieve good results with the following lenses. Click on the link to see them.
Canon 85mm 1.8--This gives you a focal length of 136 mm, and let's in twice the amount of light that your typical "kit" lens you bought with your camera. It focuses fairly quickly and would be great for sports such as swimming, volleyball, gymnastics and basketball. For Nikon shooters, try the Nikon 85 mm 1.8.
2. Boost your ISO.
Since your need to let the most light in, you will be shooting wide open at your widest aperture (2.8, 1.8, etc). You'll be trying to freeze the action too, resulting in a faster shutter speed of at least 1/800th of a second. That combination will still give you poor results at ISO 100, so consider boosting your ISO as high as you can before your images become grainy from digital noise. I often shoot at ISO 6400 on my cameras, as that gives me a fast enough exposure triangle to get the shot I want.
3. Set your Autofocus to Continuous.
Set your camera's autofocus system to AiServo on Canon, or AF-C on Nikons and Sonys. This will allow your autofocus to continually focus and refocus, so as the athletes move, the focus keeps up with them. The more expensive your camera, the better the autofocus motor will be. I also suggest that you plan your shot. Don't just be a "spray and pray" shooter who holds the shutter speed down and takes a ton of shots, praying they turn out. Think through your shot. Where is the best light in the gym, what players do I want to take a photo off, where do they tend to be positioned? In the above photo, I knew this player to be a 3 point shooter, so I waited until he was in the spot I wanted and could get the shot.
4. Shoot in Manual Mode to take full control of your camera.
Take a look at the dial on your camera. Have you ever wondered what the "M" mode was? Do you use the "Sports icon", or shoot in Aperture mode? You should give Manual mode a try. Why? Because by shooting in manual, you can set the exposure triangle to the values you want. Often times, cameras will limit you as to how high, for example, the ISO will go when in certain shooting modes. Perhaps the shutter speed will tap out at a slower shutter speed than you want. Try manual, as it lets you set your aperture to let the most light in (think lower number, like f2.8), set your shutter speed to freeze the action (think 1/800th or faster), and set the ISO to compensate for the other two parameters (think ISO 6400 for a poorly lit locale). Shooting in Manual may sound scary, but in truth, with a little practice, it allows so much flexibility in shooting.
5. Add flash, carefully!
This last suggestion needs care to try. Do not do this without asking coaches, referees, and administrators if it's ok. But, take basketball for example. If you put one flash halfway up the bleachers on the baseline and angled it towards the opposite 3 point line, and another flash in the opposite corner shooting back towards the first, and elevated them to fire above the highest action, you can gain enough extra light to shoot at a lower ISO, thus giving you better image quality. This takes some practice with off camera flash shooting as well as some specialized equipment, but if done properly ( I suggest you try it, with a coaches permission, during a practice or scrimmage to be certain it doesn't distract the players in an actual game).
I hope these simple suggestions help you get the shots you want. Feel free to email to ask questions or clarify any information. Happy shooting!