When using Fujifilm 1.4X TC WR Teleconverter, you're able to multiply the focal length of compatible lenses by 1.4x. The teleconverter increases the lens' aperture by one f-stop, however its sophisticated optical design constructed of 7 elements in 3 groups maintains the optical performance of the original lens. When used with compatible lenses, the results can be spectacular! Additionally, thanks to the unified design when mounted to a compatible lens, the teleconverter is weather and dust-resistant and operates at temperatures as low as -10°C. You can have confidence when shooting out in the wilderness when you need to get that special shot.