Here’s a tip for recording dialog that those of a more visual stripe may find both surprising and useful.
A common mistake of a lot of first time film makers is to create these stunning images, focusing very little time and effort on audio. Me personally I have always believed audio is as just important, if not more important that the visual. Meaning if you have bad audio that sounds like crap you will not watch the film, but on the other hand if you have dope audio and a sucky image the film can still be engaging. The key is knowing what mics to use under what circumstances.
These mics are used in outdoor recording situations they usually work good in very open spaces. They are very directional and usually have a super cardioid pattern. They do not work well for interior, due to the fact they will capture a lot of the rooms reverberation. Here is one that is not expensive and works very well in the field.
Rode NTG 2
All around good dialog mics.
These are the best mics for capturing dialog these are used in a lot of hollywood films and are a industry trade secret.
Sennheiser MKH 50
It may be time to revise the common advice that a lapel and shotgun are the right first investments for film and video shooters. You can not go wrong if you pick up either one of these mics.