7d w/400 f2.8 or 5d mrk1 w/600 f/4

[halsmith]

Just got back from yellowstone and want a little more reach over my 3oo f/4.  I currently have a original version 5d.
Should I add a 600 f/4 no IS
or
7d w/ 400 f2.8 no IS
budget will not let me get IS

Also, my thoughts on IS for the larger lens is that 99% of the time I would be on my heavy tripod and IS would not be that helpful.
Please share your thoughts on this

[Bob Atkins]

You need to carefully consider the weight of the 600/4L and 400/2.8L. They are very heavy lenses (I used to have the 600/4L). They require a pretty sturdy tripod and a solid tripod head to get the most out of them. I use a Gitzo 1325 with an Arca Swiss B1 and I'd say that setup would be only just adequate for those lenses. Carrying either one any significant distance (along with the tripod and head) will be a task.

If you go for the 400/2.8L make sure it's the MkII version (with fluorite optics).

Also, note that it may be difficult to get either lens repaired if it fails because Canon no longer support them and when spare parts run out they don't make any more.

I have the 500/4.5L, which is about 1/2 the weight and if I was looking for a long telephoto and couldn't afford the IS lenses, that's the one I'd go for (and I did).

I'd get the lens and then see if you need the 7D (or the Rebel T2i which has the same sensor).

I presume you've tried the 1.4xTC with the 300/4L. I've used that combination quite a lot and it works out very well.