Whenever I drive on non-Interstate Western U.S. highways I always have the longest lens that I have with me attached to a ready camera which I can grab for a wildlife shot without having to take a camera out of a bag or case or change lenses. My rationale for this is that I will normally have time to switch lenses for subjects requiring a shorter lens but will seldom have the time to switch lenses if an animal comes into view. This system has enabled me to get some nice wildlife shots which I would have otherwise missed.

I was driving in Yosemite National Park about noon today and found a lovely meadow with a pond that was backed up by the beautiful mountains surrounding the Valley. The mountains were reflected in the pond and it was a superbly photogenic sight. AND I DID HAVE TIME TO SWITCH LENSES...

I removed the 70-200mm f/4L IS lens from my 40D and replaced it with a 12-24mm f/4 Tokina. I walked out on a path into the meadow and found that the 12-24mm on my 40D and 24-70L on my 30D were the perfect focal length combination. UNTIL...

A mother black bear lead her two playful cubs out into the meadow. I don't disturb wild animals to get their picture and i certainly would not disturb a mother bear and her cubs to get close enough to use a 24-70mm lens...

By the time I hurried back to my vehicle to retrieve my tele lens; momma bear and the cubs had wandered off. If I had my usual combination of telephoto zoom and mid-range zoom out in the meadow - I would now have some neat images.

Opportunity + preparation = great images. I hear you about being prepared for almost everything but you can't always do it. When Linda and I were on our way home from the Rottie National in Colorado, I had my camera with the 17-55 F2.8IS next to me and Linda had the 200 F2.8L in a case in her lap. When we stopped for photos, she'd come with me and I felt I had 90% of what I needed for scenics or wildlife. Oh, and I had the 1.4X Canon Teleconverter in my pocket (which I never used).

At shows, I travel with my gear in a Pelican 1510 case but when I'm by myself, everything is in a backpack so I can just strap it on and go. I've still missed some situations that would have been nice but mostly, those have happened when I didn't have any camera gear at all.

Sorry you missed momma and cubs but if you're prepared, you'll get them next time. The good news is, there almost always IS a next time .

Jim

OK - So did you get the shot? Of the meadow with the wide angle? Was it as good as you had pictured it in your mind? So you missed the bears, but if you let the bears make you miss the landscape shot, then that is a real loss. Perhaps having the bears as a tiny point of interest in the landscape shot would have been the way to go.