Sensitive, precise, requires phantom power — universal workhorse on set for dialogue, ambience, music. Vulnerable to wind; always use windscreen.
On set, you reach for a condenser microphone when precision and richness of detail are paramount. Unlike dynamic microphones, it works with a thin, taut diaphragm that generates electrical voltage changes via a capacitive sensor – hence the name. This makes it highly sensitive to fine nuances: breath sounds in dialogue, the rustling of fabric, the clinking of cutlery. But this very sensitivity is also its downfall – wind becomes a conflagration, handling noise is as loud as thunder.
Practical Reality: Every condenser microphone needs phantom power (usually 48V from the audio box or mixer), without which it remains silent. While this is an extra setup step, it's the standard on a professional set – your sound engineer will give you dirty looks otherwise. Its sensitivity makes it the first choice for close-up dialogue: a good cardioid condenser (positioned at the actor's head height, for example) captures the vocal nuances you need in the edit. It's also your secret weapon for ambient sound and music recording – when an actress sings live. The audio signal prefers to be close and directional, which is why you can't compromise on wind protection. A cheap foam windscreen is often enough, but for real wind or exterior shoots, you'll need a blimp or a furry windjammer – otherwise, your dialogue will sound like a storm over the Atlantic.
Ensure your audio box provides phantom power and the cable run to the microphone is clean – long XLR cables should be taped down or bundled away from the frame. In the edit or during sync, you need clear, clean takes; a condenser offers less room for error than a robust wireless headset. For dialogue, the rule is: proximity over volume. Your sound engineer will be grateful if you position the microphone close enough so that the levels are good – and don't wildly fluctuate between -3dB and -20dB with every word.