I conducted a number of tests in JPEG format, shooting subjects around my home (utility poles, trees, etc.) at 400mm (f/4.5), 560mm, and 800mm.
The photos show greater micro-contrast and sharpness when using the 400mm f/4.5 lens on its own; however, by applying a bit of extra contrast and sharpness in Lightroom to the images shot with the teleconverter, I’m able to recover that slight edge I get with the 400mm lens alone.
In short: the 560mm and 800mm configurations are truly excellent—they just need a little bit of "life" brought back into them! 😅 But what about action, sports, or birds in flight?
My tests comparing the 560mm setup to the 400mm lens showed an advantage in terms of autofocus performance and the number of successful shots. I’ll have to see how that plays out over time...
I haven’t tried making comparisons using compressed RAW files; perhaps it’s the teleconverters that are stripping away the sharpness otherwise applied by the camera body when shooting in JPEG?
