Relatively clear morning air with decent light gave me a chance to finally put the RF 100-500mm with 1.4X extender to the test on some familiar targets. As expected, the combo was sharp, with slightly fuzzy edges on the finest details.
The good part was that images didn’t smack of cooked sharpness the way the bare lens images do. The bad part was that the extender didn’t enhance detail that much, and AF hunted even on some contrasty subjects in good light. It actually looks as though the RF 600mm f11, with a tiny bit less reach, resolves a smidgen more fine detail than the zoom/TC combo.
Having given the zoom a more than fair try on all sorts of subject matter in all levels of light, I set out in the afternoon with the RF 100-400mm with the extender in the bag. With or without TC, it’s every bit as sharp in the center as the larger zoom. The kicker is that, looking at some archives, the sharpest of all is the RF 800mm on the R6, with less relative reach than the 100-500mm/TC combo!
The 100-400mm focuses much faster and didn’t hunt or miss a single shot this afternoon. With extender, it missed critical focus on several shots, but only in low-light canopy situations where I would have been more likely to shoot with the lens alone under normal shooting circumstances.
So . . . with pluses that I don’t really need, like better across-the-frame sharpness, better build quality, and a red ring around the end; and with minuses like slow AF, weight, and miserable handling in comparison with the lighter zoom, its days are numbered.
For sure this time. If I needed any more disincentive, walking around with the extender attached and the lens (cross-body) zoomed out to at least 300mm was more than enough this morning. Attaching or removing the extender while standing in the field is close to impossible. And looking at IQ with the extender attached, I suspect its “compatibility” was the preference of the marketing department rather than the intention of the designers.
Good light helps sometimes!