Hi Geoff - Thank you for sharing your thoughts about the Extender. I'm still mulling the idea over. The online documentation says it is compatible with 100-400 lens that I would use it with but my lens is 4.5/5.6 so I may have problems on dreary days or less lighted situations. About the time I think I have pretty much what I need (or want), something else becomes interesting. Guess that is the nature of this photography beast! <chuckle>
Cheers!