Originally posted by dcshooter You are on crack if you are planning on trying to carry on the 600mm. Not only is it incredibly heavy, meaning lugging it around the airport won't be fun, but its case won't fit under a seat or in one of the newer narrower overhead bins, typically 21x14x9. The thing is enormous. You could get away with putting it uncased in an overhead bin, but would you really want a $6k piece of kit bouncing around up there?
The reason I'm selling the lens is that it is no fun to use. It is a beast and you need a beast of a tripod. It is really not suited for the opportunistic wildlife photography I do (sometimes). The lens is difficult to use due to its weight and size. You need very good technique to achieve sharp images. I use the highest ISO I can get away with even in sunshine (I've seen wildlife photographer Frans Lanting saying he does the same) so that the shutterspeed is high enough to minimized vibration induced unsharpness; better with a "noisy" sharp image than a noisefree fuzzy image..
I only recommend this lens if you are:
1. Shooting in wildlife hotspots where you are fairly certain to encounter your intended subject.
2. Shooting from a blind.
ie this lens is best for planned shots.
The only "extended" trekking with the lens I've done was to the fox den I came over a few years ago (see avatar!). It was 1/2 hour walk along a trail. I had about 10 trips. 50% hitrate of seeing the fox puppies.
I'm going to replace the 600mm with the 150-450 lens