Out with the RF 100-500mm again, this time under optimal lighting and well-lit canopy, I had a chance to try the 1.4X on some of my critter friends. The first thing I noticed was IS jitters like I’ve not seen before. It mostly stopped after a few shots, but performance of the lens paired with the TC was absolutely abysmal, so much that I wondered if I’d gotten a second bad copy of the lens.
Then I happened to notice that auto ISO was in five digits for about half of the shots! Running some of the “better” shots through Topaz Denoise didn’t help with details at all—because they just weren’t there in the first place!
The bare lens was good again, especially after some help from Topaz; but brittle sharpness in some of the feather details makes it look as though it’s cooked into the raw files, same as Sony did with their 100-400mm GM (my unsubstantiated observation). On most birds I’ve photographed so far with all three, the EF 100-400mm II and RF 100-400mm both do feathers more to my liking than the 100-500mm. Again, note that I didn’t say “better than.”
With every certainty, both of the 100-400mm lenses are much better with a 1.4X extender attached than what I saw today—again, under light as good as the lens will ever get. The amazingly high ISO is a whole ‘nother thing.
One more niggle with the lens/TC combo, on top of the awkward handling and moving about with the setup: it is easy to forget when the lens is in the 300mm position. Twice today I shot at 420mm before realizing I needed to zoom to 700mm.
Hoping for similar light again tomorrow afternoon, in which case I’ll head out with the RF 100-400mm and extender to do a direct comparison while today’s results are still fresh in my mind. The RF 100-500mm is a very capable lens on its own, yes, but anyone with either or both of the other two shouldn’t be looking to ditch them in hopes of better results.