My New Lens Doesn't Focus...
Stepped up from the kit lens, eh? Decided to get the fancy glass that all the internet forums rave about? Maybe you've ditched the old DSLR that you had for 5 years and bought the top of the range new one that has the quintuple processor and in-built beer engine. And you've gone out to take pictures at the soccer with the new fast lens under the lights and about half of them are slightly out of focus?
It's a conspiracy! It's an outrage! It's all the fault of George Bush! Of course it is. George Bush and the makers of the lens and the scientists over the years that have formulated the laws of optics. All in cahoots.
The rotters have fixed it so that f:8 has more depth of field at a focal length of 55 mm than at a focal length of 300mm. Then they have sneaked in the optical law that says that f:8 has more depth of field than f:1.2 anyway, no matter what the focal length. And they have arranged for soccer games to be held under lights rather than out in bright sunlight...forcing you to use those wider-open lenses....Appalling.
Worse - the manufacturers have put more resolution into the new sensors and screens so you can see when it is out of focus - never had that problem peering into the old 1-inch screen. It is almost as if they are taunting us.
Well, there is only one thing to do. Fight back. Go all old-school on them. Raise the ISO until you start to get coloured sparkles, then back it off a touch. Use your telephoto lens to focus manually on the grass where the action is going to be. Leave the lens focussed manually right there. Set the aperture at f:8. Set the shutter speed at 1/250 of a second if there is enough light to do it. Or 1/125 if not. When the players run over the grass bit that is in focus press the shutter button.
That'll teach 'em.