XF50-140mm now has a reliable partner to work with: XF1.4X TC WR. There will be more to come in the future that will work with the teleconverter such as XF100-400mm and 1:1 Macro lens.
Generally speaking, designing teleconverter is a very frustrating process because it will be used for multiple of lenses and there are no lenses that are same. Each has its own purpose and philosophy.
The ones that prioritize in image quality are rather easy to work with, but there are also lenses that have their priority in size or quickness. And even when we say "image quality", lenses vary in their performance as some lens works best at tele-end and some try to achieve equal high image quality throughout its range. There are also those that prioritize in sharpness, tonality, or bokeh. Lenses cannot be simply compared one to another.
Teleconverter needs to accept all these unique characteristics of each lens.
So what would make an ideal teleconverter? It should only extend the focal length and affect nothing else, so that the characteristics of the original lens would not be killed.
"The chracteristics of the original lens" also include aberrations. Teleconverter increases the aberration in its nature. It may be more apparent than before.
"It would have been better if the photo had just been cropped". It is true that there are some teleconverter and lens that may not work so well.
So how about XF1.4X TC WR? You are in luck.
Because the original lenses are of quality lenses.
The 4 X-photographers tested the 50-140mm & XF1.4X combo during the WEC, and they all approved.
The teleconverter maintains the sharpness, bokeh, quickness, and all other characteristics of the 50-140mm and only extends the focal length.
Continue to read Episode 12
One lens one story - Episode 12: XF1.4X TC WR Part 2
#1 XF14mmF2.8 R
#2 XF23mmF1.4 R
#3 XF60mmF2.4 R Macro
#4 XF35mmF1.4 R
#5 XF27mmF2.8 Part1
#6 XF27mmF2.8 Part2
#7 XF56mmF1.2 R Part1
#8 XF56mmF1.2 R Part2
#9 XF18mmF2 R
#10 XF18-135mmF3.5-5.6 R LM OIS WR
#11 XF1.4 X TC WR Part1
#12 XF1.4 X TC WR Part2