Definition of extension tube in English:

extension tube

noun

Photography
  • A tube fitted to a camera between the body and lens to shorten the distance of closest focus of an object so that close-up pictures can be taken.

    • ‘If you are using a camera like these, an extension tube or a close-up lens is the ideal tool.’
    • ‘I would also get some extension tubes, you can use these on both of the zoom lenses.’
    • ‘Available options include infrared LED spotlights, backlights, and lenses for cameras from 6 to 75 mm, plus filters and extension tubes.’
    • ‘I have been there when the Puffins are so close that you couldn't even focus on them with a 300 mm F2.8, without using an extension tube.’
    • ‘An extension tube radically reduces that minimum focal distance.’

Pronunciation:

extension tube

/ikˈsten(t)SHən ˌt(y)o͞ob/