Microphones can usually be oriented in order to point to a sound source we need to record. Dynamic microphones do not have a far reach, and thus are usually limited to the sound right in the front of the capsule. This is called a cardioid pattern.
Condenser microphones can usually choose among a few patterns.
Cardioid is the most used figure. On stage, it is a must, as it excludes the noise coming from the public and the reflections of the hall. We can imagine like a beam coming out from the microphone and picking up everything it finds in its traiectory. Some not so common variations include the hypercardioid and supercardioid figures, which have a variable sensitivity also in the rear of the microphone.
The cardioid pattern is the most sensitive to the proximity effect - i.e. as you get closer to the sound source, the basses are enhanced.
The figure of eight picks the sound equally in the front and the rear of the microphone. It is typical in condenser microphones and the only option in ribbon ones. Thus, the rear must be screened if it is unwanted. The sides are excluded from the recording, using this figure.
The omni pattern is omnidirectional and can pick up everything in the hall. In this case, there is nothe proximity effect. We can easily capture ambient sound.