Lens size, depth of field, focusing
Posted 15 June 2007 - 02:56 AM
Posted 15 June 2007 - 10:11 AM
A 12mm lens, with a CoC figure of .0010", focused at 3', stopped down to f/5.6, will have a range of acceptable focus from 1' 7" to Infinity -- is that good enough for you?
The short answer is that with a wide-angle lens stopped down, focusing is generally easier -- but it's hard to shoot an entire movie that way.
You should worry about focus -- it's part of the filmmaker's tools and cinematic grammer. Avoiding it is just being lazy unless you have a good reason, like creating deep-focus compositions with important information happening far and near, for symbolic effect.
Otherwise, you get into the problem that consumer DV has, where almost everything is in focus due to the small target area. It's a bit unattractive. Focus is a form of information delivery, so if everything is in focus, then everything competes with everything else for attention.
Just use a Depth of Field chart to see the range of focus for different combinations of focal length, f-stop, etc.
Posted 16 June 2007 - 09:18 AM
Posted 16 June 2007 - 10:20 AM
If you are going to get close, it's good to just see how close you can get before you hit minimum focus on the lens, memorize that shot size, so that when you walk up to something tight, you turn the focus ring until it bumps at the minimum focus end and frame the shot knowing how close you're allowed to get.