Lenses for Safari

I am going to be going on my first safari this september and am looking for advice on what focal lengths are going to be most useful for me.

A majority of my photos are going to be taken early-mid morning and mid-late afternoon and I envisage that I'll mainly be photographing large(ish) mammals but there will no doubt be some birds that I want to capture.

I'm currently using a 350d and have the 17-85 IS (f4-5.6) and 70-200 IS (f4), with the crop factor of the body this essentially gives me coverage of 27-320. In your experiences is this going to be long enough?

Should I be looking to buy a faster / longer lens or a 1.4x TC for the 70-200? Weight is an issue as we'll be using light aircraft to get around and will have a total luggage allowance of 15kgs...

Would a second body be useful? I'm thinking of maybe a 30d?

Are there any tips from seasoned travellers on getting the most out of wildlife photography?

Many Thanks in advance for all your wisdom and advice
Mark

I use the 100-400 the most while on Safari. If I bought anything longer, I couldn't afford to go.

You usually don't need a long telephoto lens to photograph big animals in Africa, but there are lots of small animals and colourful birds, sometimes animals like rhino don't come close to the vehicle and sometimes you want to do intimate face only portraits of large animals. I want to have as long a telephoto lens as possible.

My favorite lens for African wildlife is a Sigma 50-500, but I usually have a private vehicle and use a window-pod mounted on the door. If you are going to be using a group safari vehicle it will probably be best if you can hand hold the lens and should have IS on your long telephoto lens. For this purpose I would recommend the Cannon 200-400 IS. You give up a bit on zoom range compared to the 50-500, but the IS is invaluable if you have to hand hold in anything but mid-day sun light conditions.

Most of the time you do not need a very fast lens, although this is always helpful. I have used my 70-200 f/2.8 when I did walking safaris in dense undergrowth where light is limited, such as chimpanzee or gorilla trekking in Uganda. I would not have been able to get some of my shots on those occasions if I did not have an f/2.8 lens because I would not have had a fast enough shutter speed.

Add on a 400mm 5.6 L ... most effective route IMO given what you have. As ScottE says if you are not self drive then a long IS lens is better and the best all rounder is the 100-400mm IS L. The Sigma 50-500mm is also very confincing in real world safari shooting. I've had all of them.

For my next trip in August I am taking the 70-200mm 4.0 IS L and 400mm L. Also taking a 1.4x for use when needed.