A flexible, light-tight tube that folds like an accordion. It connects the lens to the camera body and lets you change the distance between them. Bellows have been used on cameras since the 19th century and are still standard on large-format view cameras. There, the flexible bellows allow camera movements such as tilt and swing, which control the plane of focus.
For close-up and macro photography, a bellows unit can be placed between the lens and the camera. It works like an extension tube but can be adjusted smoothly and can give greater magnification.
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