@Freezer@mastodon.social You've not lost any sharpness by the look of it. I had a Canon 1.4 that I used with a 70-200 and it was pretty decent at the long end (where I really needed it).
@tk @Freezer@mastodon.social I used to photograph a lot of aviation back in England and at my local airfield and 200mm wasn't always enough for smaller subjects. The Canon TC was optically very good and didn't hurt quality either.