Let me start off by asking a few questions. What kind of budget do you have for audio? Which camera are you using?
Yes, a wired lav mic will give you the best results assuming that the subject is fairly stationary. Lav mics need power to operate, either phantom power (which your camera does not supply) or a power supply with a battery compartment. Not all power supplies have this compartment; some only convert phantom power to the necessary voltage for the mic.
Tram TR-50
http://www.trewaudio.com/store/product.php?productid=383&cat=45&page=1
Sony ECM-77
http://www.trewaudio.com/store/product.php?productid=786&cat=122&page=1
Both of these mics are available with battery powered supplies for under $400. You will get high quality sound with these mics.
Next you have to get the mic signals into the camera, which means you'll need a special XLR to 1/8" adapter, such as the one found here:
http://www.trewaudio.com/store/product.php?productid=146&cat=31&page=1
The next big question is: how much control does your camera allow over the audio levels? You need to be able to adjust the levels at the camera.
Hope this helps.
Rodney
Freelance Sound Technician/Mixer
