The XF 2x TC WR Teleconverter from Fujifilm is high-performance teleconverter designed for use with their XF 50-140mm f/2.8 R LM OIS WR and XF 100-400mm f/4.5-5.6 R LM OIS WR lenses, where it will multiply the focal length by two. This is done while retaining all communications between the body and lens including metering, autofocus and image stabilisation, as well as the transmission of EXIF data. 9 elements in 5 groups maintain the optical performance of the original lens. It features a weather resistant design to match the rest of the Fujifilm system, with a sealed construction that reduces the chances of dust, water, or even the cold from affecting performance. Note that your aperture becomes two f-stops higher when the teleconverter is mounted, and the camera displays and records information reflecting the change in aperture and focal length. Compatible Lenses: XF 50-140 f/2.8 R LM OIS WR XF 100-400mm f/4.5-5.6 R LM OIS WR