A feature you will usually see on professional camcorders, but never on consumer ones, is XLR. There are a number of different types of XLR but the most common one on camcorders, XLR3 (also known as â€˜balanced audio'), is a special three-pronged plug used to attach pro-grade sound equipment. You will pay a significant premium for this feature, however. For example, Sony's HVR-V1E costs around Â£2,500 inc VAT but its consumer equivalent, the HDR-FX7E, is about Â£300 cheaper - with the main difference being XLR3 connections.
Aside from being a big, sturdy connector, XLR3 has one other, very important feature. Its third wire is used to cancel out any hum picked up on the cable. This means you can have long cables without ruining the signal. If you make video for a living, this is a major reason to buy a professional camcorder model rather than a consumer one. However, you can add the feature to any camcorder with minijack microphone inputs using an adapter such as Beachtek's DXA-4, which is only Â£175 - much less than the premium usually charged for a camcorder with XLR built in. If you are aiming for professional results, XLR is a must. But it adds to the cost of your microphones and wiring as well as just the camcorder.