Comments about Tenba Think Tank Lens Drop In, for Changing Teleconverters.:
I use this to swap between my primes (Canon 35, 50, 85) quickly while on a shoot or just drop something in, lens cap, battery, whatever, if i need a free hand. i suggest two of these, this one and the "Large" one for like the Canon 16-35 f2.8L . Oh, sure you can drop in a teleconverter too.
It never completely closes, so in inclement environments, use the rain pouch on the bottom for dust/rain/snow etc. if i had a choice, i'd replace my skins with these, if they were bigger for 70-200 kinda thing.
Nice addition to the ThinkTank system.