Bob, thanks for your comments and ideas… I think I have found a solution that will work for me. I was loathe to pay almost $400 for a battery grip from Canon for my 5DIV, and ended up purchasing a GREEN EXTREME BATTERY GRIP Model GXBGE20 from ADORAMA for about $70. It works well and I have seen no loss of functionality through it's use. Tried to buy a replacement battery tray from ADORAMA - no dice, no, nope, no way, nyet - so I purchased another battery grip complete from ADORAMA for $70 to get an extra tray. Of course, just a few weeks later, they were selling the exact same grip for $39 - hah! Around the same time, I was able to purchase a RUGGARD DSLR PARKA (PAC-LB) for about $30 from ADORAMA as well. It appears that the PARKA will fit my 70-200 2.8 + Extender as well as the 16-35 f:4.0 This item is advertised as a "Cold and rain protector". This product looks like it will do the job I'm wanting to do. So now, I have a "parka" to keep the camera and it's 2 batteries warm(ish) and a spare tray with 2 more batteries to hold in an inside pocket for switching out when needed. All of the batteries will be secured in their respective trays with scotch tape (removable, of course) making handling safe and worry free. AANNDD…I've got a spare battery grip if I need it (or don't). I'll take additional steps to protect against salt water and salt spray when going ashore in the Zodiak. I also like the idea of a longer "wake time" for the camera to allow the electronics to help keep the camera warm(er) Well, I thought some contributors might be interested in these musings. Oh, and I do do business with B&H, also. Wm700293
