A teleconverter is a lens accessory that fits between a camera body and its lens to increase the effective focal length, typically by 1.4x, 1.7x, or 2x. This allows photographers to achieve greater magnification and bring distant subjects closer without changing their primary lens.
Teleconverters are commonly used in wildlife, sports, and action photography, where extra reach is essential. While they increase focal length, teleconverters can slightly reduce light transmission and may affect autofocus performance, so understanding their use is important for maintaining image quality and achieving sharp, well-exposed photographs.