The following assumes that you have a basic understanding of aperture and how it affects shutter speed and depth-of-field. If you’d like a quick refresher, the following links should help:
Or use a search engine – there are lots of good explanations out there.
My recommendation is that you set your camera to F4, and then adjust your ISO to give you an acceptable shutter speed (I prefer 1/1000th or faster, though I’ll accept a bit lower if necessary).
If you know a bit about how the pros shoot, that may be a surprising recommendation. Most pros use big and expensive F2.8 lenses. So, why F4? Well, I think it’s the best compromise aperture, and will give you the highest percentage of good shots, especially if you’re starting out. In most cases…
To understand that â€œusuallyâ€, it’s useful (or at least I think it’s useful – you are welcome to post a comment telling me that I’m deluded) to discuss what a smaller aperture would do.
2.8 Gives us…
A smaller aperture will definitely give you a nicer background. But it’s not going to turn those parents on the sidelines into a slightly mottled background, it’s going to turn them into slightly blurrier parents, with an emphasis on â€œslightlyâ€. Blurrier is better, but I’m not sure you’re going to notice a the difference.
Less depth of field
The same thing that gave us a blurrier background gives us less depth-of-field on our subject. To take an example, my 40D @ 200mm and F4 gives a depth of field of about 5′, front and back. Step up to F2.8, and that reduces to about 4′. That doesn’t sound like a big difference, but it’s 1′ less margin for error in your autofocus system, and 1′ less range where two players can be. And I suspect that the calculated depths-of-field are a bit too big, since sharpness is so important in sports shots. I know I have shots at F4 where I wish for a bit more depth-of-field, and F2.8 makes it worse.
Worse lens performance
My 70-200mm F2.8 L lens is pretty darn sharp at F2.8. But it’s sharper at F4, and that’s for a lens that is explicitly designed to be very sharp wide open. Most lenses are better one stop down from the widest aperture.
So, I’m suggesting F4, yet I spent the money and deal with the weight of the F2.8 over the F4 variant of the same lens. Why?
It’s simple. Light. My daughter’s lacrosse team plays in the evening, and they also play on some pretty gloomy weekends, and that means I don’t consistently have the light that I want. If I don’t, my options are to bump up the ISO (more noise), reduce the shutter speed (blurry players), or shift to F2.8. That’s when the F2.8 really earns its keep.
If you shoot indoors or under stadium lights, you have my condolences. I’ll talk about indoor/night shooting in the future.
What if my lens only goes to F4?
If you only have a lens that goes to F4, I recommend trying both F4 and F5.6 and seeing what you think. If you have (for example) a Canon 70-200mm F4L, I think you’ll be happy with the F4 performance. But if your lens isn’t good enough, you may be looking at a lens upgrade, I’ll talk about that in a future post…