Upload & Sell: Off
Thanks for the feedback folks.
@trenchmonkey: If I understand the concept of the donut, it fits btw the lens and the body. I was under the impression that Lenscoat covers wrap around the barrel. No?
@abqnmusa: I grant your point re the vulnerability when changing lenses. Absent controlled tests, we can't be sure whether this donut thing actually adds some measure of protection. And it would do nothing to address the dust sucking of a push/pull lens like the 100-400. Neverthless, I'm sufficiently paranoid about dust that I'll probably spring for it.
@diverhank: Thanks for that insight. Have been in really dusty conditions in East Africa and went through a lot of gyrations to keep the dust at bay.
@StillFingerz: Looking forward to your field report.
@John Caldwell: You may be right John; there's so much of that these days (ASISOAP, that is). Still, I wonder if the donut might give some added, albeit marginal protection. I guess I'm cheap enough to post the question and paranoid enough about dust to buy something that may be useless.
Again, thanks all for your f/b.