Century 0VS-16TC-MXL (VS-16TC-MXL & VS16TCMXL) 1.6X Tele-Converter & 16x Manual / For Canon XL2 with 16X Manual Lens & for JVC GY-DV5000U with Canon YH16x7
Add the 1.6X Tele-Converter to the front of your zoom lens to shift its focal range in the telephoto direction.
The perfect tool when it's inconvenient & dangerous & or even impossible to move as close to the subject as you'd like.
There is no appreciable light loss.
Note that the Tele-Converter offers partial zooming & vignetting will occur at mid-range through full wide angle.