Which Lens Should I Take?

[bogino]

Not an Professional photographer but an "avid" one.  Have a decent collection of lenses for my Canon T1i.  Just thouyght I'd seek an opinion here:

Traveling to Central America next month and plan to spend a good deal of time in the rainforest shooting (with a camera that is...) wildlife.  I have 2 400mm lenses which are as follows:

Sigma 120-400mm f/4.5-5.6 DG OS HSM
                   and
Canon EF 400mm f/5.6L USM

One obviously has soom zoom while the other is fixed focal.  I envision using these for pictures of monkey's in trees...birds..cats...etc.  I'm curious from those of you that are experts on these as to which of these 2 lenses I should take with me and why?  Thanks for your input.

[Bob Atkins]

As always...."It depends".

For example what other lenses do you have that cover the range up to 400mm? You're probably going to want 100,, 200 and 300mm at some times.

Will you be using a tripod? While I'm pretty sure the Canon 400/5.6L is sharper at 400mm than the sigma zoom, it's not stabilized so if you are hand-holding it the images may not be as sharp if your shutter speed drops much below 1/400s.

You also have the two lenses to compare, so you can tell how much image quality you're loosing by using the Sigma zoom. Is the Sigma quality at 400mm good enough for you?

Just looking at it from a theoretical point oif view I'd say that you'd probably get more "keeper" shots with the optically stabilized Sigma zoom, but you might get higher technical quality (but fewer) images from the Canon prime (assuming you have it on a tripod and/or shoot at 1/500s and faster).

If I could take only one of those lenses, I'd probably go for the Sigma because of the versatility. On the other hand if I also had something like a Canon EF 70-300/4-5.6 IS USM  lens with me, I'd take the Canon 400/5.6L

[bogino]

I don't have a 200mm or 300mm lens.  Besides the 2 400mm lenses I referenced I have an EF 85mm 1:18 and a EF 100mm 1:2.8 USM Macro.  My plan was to take the 100mm Macro with me for close up (bugs--plants--flowers etc.) rather than the 85mm.

Also taking my EF 18-135mm IS to use as a more "all purpose" lens.

I don't envision using a tripod with the 400mm when taking pictures of moving animals (monkeys...if I'm lucky a cat such as a puma or jaguar..parrots..).  I'll only have a split few moments to try and capture those so it seems from your comments like the Sigma might offer better versatility. 

Also--got any recommendations on a good "wide angle" type lens?  I don't have any wide angle at this time.  I'll be in Costa Rica and Colombia.  Thx.