Cheap Microphones - An Explanation.

If you anticipate moving into semi-pro or drama videomaking then you should be looking at something like the Rode NTG3 or the Sennheiser k6 series. In the past Rode, although known for good value studio microphones, hasn't had a good reputation for video mics. Its chinese-made NTG1 and NTG2 were not at all good however the NTG3 seems to have broken the mould and is getting good reviews for a £500 shotgun microphone.
http://uk.rodemic.com/microphone.php?product=NTG-3

The Sennheiser range consists of a base unit (the K6) and a selection of capsules which are fitted onto the K6 depending on what type of characteristics you want. This has the advantage that you don't spend as much on a range of microphones as you would buying a non-modular set of mics.The most common capsule is the ME66 shotgun. Sennheiser mics are known for their clarity and nice tonal qualities.
http://www.sennheiser.co.uk/uk/icm.n...microphones_k6

If you're just going to have your microphone attached to your camcorder and only want it to replace the in-built mics for general shooting, then a shotgun is probably a bit too directional for this purpose. You need a "cardiod" or "hypercardiod" microphone. These accept sound from the front and (to some extent) more from the sides than a shotgun. With a narrow pattern (shotgun) mic, anyone off the axis will sound strange as some of the vocal frequencies are filtered out and others remain. It means that the camera has to be pointed directly at the sound-source. Not always possible, or what you want.

The two decent (but not cheap) budget hypercardiods which I recommend are both modular systems. This means that you can change the capsule to another one, depending on your needs. One system is the K6 from Sennheiser. The other, which I prefer, is the "Blueline" series from AKG which is very good indeed and a reasonable price.

http://www.akg.com/site/powerslave,i...nguage,EN.html