There are many different types of microphone in common use. The differences are usually described in two ways: The technology they use (e.g. dynamic, condenser, etc) and their directionality (e.g. omnidirectional, cardioid, etc). In addition, microphones have a number of other characteristics which need to be taken into account.
When choosing a microphone, the first thing you will need to know is what characteristics you need. After that, you can worry about things like size, brand, cost, etc.
Things to Consider
Work through each of these characteristics and determine your needs.
Decide which type of directional pattern best fits your needs. Remember that it's usually better to use a less directional mic in a position close to the sound source, than to be further away using a hypercardioid.
Make sure the mic's frequency response is appropriate for the intended use. As a rule of thumb flat response patterns are best, but in many cases a tailored response will be even better.
The rule of thumb is: Low impedance is better than high impedance.
Remember that the diaphragm works by converting vibrations from sound waves into an electrical signal. Unless the microphone has some sort of protection system, the diapragm can't tell the difference between a desirable sound wave vibration and any other sort of vibration (such as a person tapping the microphone casing). Any sort of vibration at all will become part of the generated audio signal.
If your mic is likely to be subjected to any sort of handling noise or vibration, you will need a mic which will help prevent this noise from being picked up. High quality hand-held mics usually attempt to isolate the diaphragm from vibrations using foam padding, suspension, or some other method. Low quality mics tend to transfer vibrations from the casing right into the diaphragm, resulting in a terrible noise.
Note that lavalier mics don't usually have protection from handling noise, simply because they are too small to incorporate any padding. It is therefore important to make sure they won't be moved or bumped.
Purchasing a Microphone
If you can afford it, it makes sense to buy a range of microphones and use the most appropriate one for each job. If your budget is more limited, think about all the different things you need to use the mic for and try to find something which will do a reasonable job of as many of them as possible.
For vocalists a simple cardioid dynamic mic (such as the Sure SM58) is a good starting point.
For video makers, a useful option is a condenser mic with selectable directionality, so you can change between cardioid and hypercardioid. If you can afford three mics, consider a hand-held dynamic, a shotgun condenser, and a lapel mic.
In the end, sound is quite subjective. You really want a mic which will provide the sound you like. A good idea is to set up a contolled test. Record the same sounds using different mics, keeping all other factors constant.
Make sure you are comparing apples with apples; for example, don't compare a hand-held cardioid and a shotgun in the same position. If you do want to compare these mics, make sure each is placed in its optimum position.
MAONO is an innovative designer and manufacturer of Lavalier, Podcasting, Wireless, Shotgun, Recording microphones and accessories for Smartphone, Camera and PC, etc.