High performance optics
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, excellent imaging performance with great aberration suppression is still achieved. The aperture becomes an f-stop higher when the teleconverter is mounted, and the camera correctly displays and records information reflecting the change in aperture and focal length. The camera system's optical image stabilization performance is unaffected by the addition of the teleconverter.
The addition of the teleconverter does not affect the autofocus performance of the camera system. An AF speed equivalent to that of the lens by itself is still achieved when the teleconverter is mounted. Accurate focusing at super-telephoto focal lengths with a shallow depth of field is possible due to the AF performed by the image sensor and the Live View feature on Fujifilm X-series mirrorless cameras.
Thanks to the unified design when mounted to a compatible lens, the teleconverter is weather and dust-resistant, and remains operable at temperatures as low as -10°C. Using the teleconverter with a weather-resistant camera, such as the Fujifilm X-T2 or Fujifilm X-Pro2 mirrorless cameras alongside the Fujifilm XF 50-140mm f/2.8 or Fujifilm XF 100-400mm f/4.5-5.6 lens does not affect the weather resistance of the system.
The teleconverter’s high grade metal exterior has been designed with the Fujifilm X-system in mind. When attached to compatible Fujifilm lenses, the two products appear as one single lens.