Dynamic microphones function by having a membrane stretched across a frame with a metal coil over it. The membrane vibrates and the coil sends the signal into your preamp. A condenser microphone has a (roughly) similar design except that it is a charged microphone that has power going into it. It doesn't need a preamp a lot of the time. A ribbon microphone is similar in concept to a cartiod microphone (the generic name for dynamic and condenser mics) except instead of a coil over the membrane you have a fine ribbon. Ribbon microphones are outrageously expensive and are super sensitive. I don't suggest a ribbon microphone.
If you want the utmost sensitivity (on a reasonable level) you should go with a dynamic microphone. You will however need a preamp and some sort of software to edit the audio. Condenser mics can cut out some of that middle equipment, but the sound quality can sometimes be less that what you are wanting.
microphones
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