The "FUJINON TELECONVERTER XF1.4X TC WR" is a high-performance teleconverter capable of multiplying the focal length of mounted lenses* (* Compatible lens (As of October 21, 2015) XF50-140mmF2.8 R LM OIS WR) by 1.4x. Although the aperture becomes one f-stop higher when mounted, the teleconverter features an excellent optical design with a construction of 7 elements in 3 groups to maintain the optical performance of the original lens. Also, 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. This makes it possible to be used with confidence outdoors when used with the weather and dust-resistant FUJIFILM X-T1 camera body and XF50-140mmF2.8 R LM OIS WR lens.
High image quality design which maintains the optical performance of the original lens
Construction of 7 elements in 3 groups maintains the optical performance of the original lens. By using the optimal image quality parameters for the overall characteristics of the original lens and 1.4x teleconverter, an excellent imaging performance with great aberration suppression can be achieved even when the focal length is multiplied by 1.4x. The camera displays and records information reflecting the change in aperture and focal length when the teleconverter is mounted.
The camera’s autofocus performance is unaffected by the addition of the teleconverter
An AF speed equivalent to that of the lens by itself is still achieved when the teleconverter is mounted. Thanks to mirrorless cameras’ “Live View” Contrast Detection autofocus, shooting at minimum aperture values is still possible despite the f-stop being increased by mounting the teleconverter. Also, accurate focusing at super-telephoto focal lengths with shallow depth of field is possible thanks to the AF performed by the image sensor.
Weather and dust-resistant and -10°C low-temperature operation
Using the teleconverter with a weather-resistant camera and lens, such as the "FUJIFILM X-T1" premium mirrorless camera and the "FUJINON LENS XF50-140mmF2.8 R LM OIS WR", does not affect the weather resistance of the system.
High-grade subtle appearance
The teleconverter’s high grade metal exterior has been designed with the X system in mind. When attached to a compatible FUJINON lens, the two products appear as one single lens.
A firmware update is required for the camera body as well as the "XF50-140mm F2.8 R LM OIS WR" lens in order to provide full compatibility. This firmware is planned to be available on October 29th 2015. Please note that when updating firmware, make sure to update the camera firmware before updating the lens. Please refer to the following website for information on how to confirm your firmware version and its update methods.
Fujifilm Firmware Website