Teleconverterequipment
A small adapter between body and lens that multiplies focal length (1.4x or 2x).
A teleconverter adds reach — a 1.4x turns 400mm into 560mm — but costs light (a 1.4x loses 1 stop, a 2x loses 2) and a little sharpness/AF speed. Only some lenses are compatible.
Use this when
- Need more reach for wildlife: 1.4x on a fast tele
Common mistake: Putting a 2x on a slow zoom and ending up too dark to autofocus.