First world problem here. I've had the 70-200 2.8 mk1 for a while now and I'm used to it and understand it's nuances (the few there are), but recently I got a 100-400 mk1 as a hand-me-down from a family member who just upgraded to the mk2. I tried a few shots off my back porch and had pretty good results. After doing some research on it, it seems this 100-400 mk1 is generally good all-around, with the exception of being a little soft wide open at 350mm or longer. I just don't have enough time to fully test it on my crop body and get used to it before my trip. I shoot with a Canon 70D (crop sensor), and I also have a 1.4x mk2 extender I can bring as well. So I pose the question to you - which lens (or both) and/or extender would you take on a trip where you had to carry all your gear all the time? More details below:
I'm taking a 2 week trip to Alaska with the whole family (grandma, siblings, pregnant wife, 2yo son), about 9 days on land, and 4 on a cruise before heading home. I'll be photoing everything - shots around town, typical family snaps, lots of landscapes, and some wildlife (including a river excursion for some eagles). Some shorter hiking, a plane ride to the glaciers, exploring the towns and seeing locals, Denali national park, cruise (shots on the boat, from the deck of the boat, from docks, towns), etc.
I have a 10-18mm for wide, and a 17-55 f/2.8 for my walkaround lens. When I use my 70-200, it's usually at the shorter end - 70mm on a crop body is pretty "zoomed in" already. One concern of mine is the big gap from 55mm to 100mm if I were to only bring the 100-400; however, I'm in Michigan so any kind of landscape photography here is really not over a vast range (flat). As for reach, the 1.4x extender gets me to 280mm on the 70-200, or a whopping 560mm on the 100-400 (but I lose AF on my 70D - annoying but not a deal breaker). Also, the 70-200 is 2 stops faster, which might make a difference (especially if stopping down slightly for sharpness on landscapes), although I'm told this time of year the sun never sets in Alaska, so there may not even be a golden hour or dusk for lower light pics. Having some telephoto range would be nice, possibly for landscapes, but primarily wildlife, and just for fun (e.g. binocular substitute). If I had to pick an order of importance for these two lenses, it would be landscapes first, wildlife second.
I have plenty of space in my pack, so that's not an issue. I just don't know if bringing both lenses would be worth the weight as I'll be carrying all my gear everywhere I go, plus stuff for the wife and kid usually.
Details on my pack and stuff to carry here:
Thanks in advance for any thoughts.