Mirrorless is a good starting point because it avoids mirror slap, but many mirrorless cameras still make noticeable noise from the mechanical shutter. If quiet operation is a priority, look for a camera that offers an electronic shutter or silent shooting mode. That can be nearly silent, though it may introduce rolling-shutter distortion if subjects are moving.

The most reliable way to judge shutter noise is to try the camera in person. Visit a camera store or seller and listen to different models yourself; that’s much more useful than relying on review videos, where audio recording and editing can hide the real sound level. Store staff may also be able to suggest especially quiet models.

So in practice: prioritize mirrorless bodies, check whether they have an electronic shutter/silent mode, and if possible test them in person before buying.