Push-pull.

A zoom lens design in which the photographer adjusts the focal length by physically lengthening or shortening the length (pushing or pulling) of the barrel in a telescoping fashion.

Such lenses have their focal lengths held in place by friction and so are prone to zoom creep. For this reason two-touch zoom lenses, which aren’t as vulnerable to the problem, are often preferred. Push-pull designs might be better if you need to zoom rapidly though less precisely.

cf. focal length, zoom creep, two touch.

Entry last updated 2002-04-19. Term 980 of 1487.

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