single lens belt pouch

I work in a horticulture department and generally use two lens, my Tam 16-300 and 90 macro. I am often swapping them off documenting plants, flowers, and insects. I have a large carry everything bag, but I don't like hauling that around the nursery, so I would like to find a simple belt bag that will hold either of the lenses when not in use, allowing a quick swap as needed. I have looked at B & H and Adorama, but there are just too many items to go through. Any suggestions?

wev when i did carry 2 lenses i just hooked the lens bag/string onto my BR strap and let it sit under my arm, or attach it to a quick release clip and loop it thru my belt strap.

I tried that but it banged around too much. I just ran across a nice lowpro that will do nicely and cheap.