With numerous anecdotal claims of gear underperformance to my credit, one might wonder if my findings are fact or fancy (see justification).
When the recent Sony 100-400mm GM acquisition, a secondhand, appeared to be not up to snuff, I decided to compare it to a couple of other options of comparable relative reach. Crops of the photos are posted below at 200%.
First shot is the GM zoom with a 2X teleconverter attached on the a7 IV, the longest relative reach at about 934mm:
Next is the Sony 200-600mm on the a7 IV, just the lens, relative reach about 700mm:
And, going a bit to the extreme, last shot is the humble RF 100-400mm on the R7, relative reach about 748mm:
To me, the interesting part is that the consumer-level RF 100-400mm shows more detail without a teleconverter than the pro-level FE 100-400mm GM lens can with a teleconverter!
The problem with the lens seems to be more pronounced at longer distances, hardly noticeable at near. One could reasonably assert that I’m being nitpicky, too. But without going back into my files for examples, I know the Sony lens is capable of better sharpness. At least one user on a popular forum reported a similar issue.
The lens was dropped off this afternoon at Sony service center where yet another offputting policy of a gear manufacturer was declared: despite the lens being out of warranty, if it is found to be a lens that was not sold originally here in postage-stamp land, the (exorbitant) labor rate for repair will be doubled!
Yeah, I know. Lesson learned. Big time.