Motorsports/airshow lens lineup...which would you choose and why?

So just mulling over a potential trade and wondering. If all you shoot is motorsports and airshows what would you choose for a linueup with the cost being ~3000 or less:

Mind you these will be on a 1D MK III:

Sigma 120-300 OS 2.8 + 1.4x TC
Sigma 50-500 OS + Sima 70-200 2.8 OS + 1.4x TC
Canon 70-300L + 400L 5.6 + 1.4x TC
Canon 70-200L 2.8 II + 1.4x & 2.0x TC
Canon 300L F4 + 400L 5.6 + 1.4x TC

or Other.

Hmmm or just order the new "Sports" series 120-300 OS (2013 model).

70-200 f/2.8L IS MKII and the 400/5.6 based on your 'value' of your choices.

fiveohmike wrote in post #15716518
So just mulling over a potential trade and wondering. If all you shoot is motorsports and airshows what would you choose for a linueup with the cost being ~3000 or less:

Mind you these will be on a 1D MK III:

Sigma 120-300 OS 2.8 + 1.4x TC
Sigma 50-500 OS + Sima 70-200 2.8 OS + 1.4x TC
Canon 70-300L + 400L 5.6 + 1.4x TC
Canon 70-200L 2.8 II + 1.4x & 2.0x TC
Canon 300L F4 + 400L 5.6 + 1.4x TC

or Other.

This is what happens when a Sigma 150-500mm optical stabilizer lens is used to capture motorsports and air show images.

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Since for Motorsport you need versatility:
Canon 70-200L 2.8 II + 1.4x & 2.0x TC

But did you think about the Canon 100-400?!
A lot of people use it to shoot Motorsport, I had the cance to try it, and it is an Excellent lens.

NemethR wrote in post #15717197
Since for Motorsport you need versatility:
Canon 70-200L 2.8 II + 1.4x & 2.0x TC

But did you think about the Canon 100-400?!
A lot of people use it to shoot Motorsport, I had the cance to try it, and it is an Excellent lens.

I sold my 100-400L a while back. I just can not get over the push/pull :/

For motorsports (road courses with a lot of opportunities to walk around) I use a 70-300L and 400 5.6L. Used to use my 70-200 2.8 mkII, but I found I was fiddling around with teleconverters too much. Also used to use a Sigma 120-300 2.8 OS, but it's a big lens to lug around in the heat all day, and I don't like using a monopod if I can avoid it.

So- I've tried some of the combo's you're considering, and found that when I combined weight/IQ/cost/conveni​ence standpoints, the 70-300L and 400 5.6L gave me the best options, with only one lens to switch around if needed, in a lightweight package. I also find the lens hoods easy with this combo- the 70-300L is small enough that I just put the hood in position and leave it there for the day, and the 400 5.6L has a hood that pops out itself.

Also note- I've used a non-reporting Kenko 1.4TC with my 7D on the 400 5.6L and had good results with focus on everything but the center focus point. With a 1D MKIII the 1.4TC would be great on the 400 since it's actually designed to focus at f/8.

My choice would be the 70-200 2.8LII with the extenders for the best versatility and quality.

NemethR wrote in post #15717197
Since for Motorsport you need versatility:
Canon 70-200L 2.8 II + 1.4x & 2.0x TC

But did you think about the Canon 100-400?!
A lot of people use it to shoot Motorsport, I had the cance to try it, and it is an Excellent lens.

shadowcat wrote in post #15718452
My choice would be the 70-200 2.8LII with the extenders for the best versatility and quality.

Canon 70-200L 2.8 II + 1.4x & 2.0x TC is the route I've moved onto for it's versatility plus I don't have an unlimited budget for lens. I don't normally shoot air shows but do shoot motor sports and a lot of other types of things.

As it goes for the motor sports side, some of things I like to shoot are under the lights & don't require that much reach so the 70-200L 2.8 II works perfect for that. Usually the times I need the longer reach it's under bright sun and the extenders do pretty well. I do plan to add a 400mm prime to my stable so I can minimize the use of the 2x TC (for if I need 800mm) to bring back some IQ/AF speed when I need 400+. Ultimately I'd like to have my 70-200 and add the yet to be released 200-400 + 1.4x, but that new lens will cost as much as all my already quite expensive gear put together.

If your going to be mainly shooting things that require 400+ the Canon 70-200L 2.8 II + 1.4x & 2.0x TC combo might be the best way to go.

I've been debating some of the same issues for a telephoto. The Sigma (I've been looking at the 50-500 OS instead of the 150-500 OS) has better image stabilization which could be helpful at airshows when you want the shutter speed slowed down enough to catch prop blur. I've heard that the 100-400 focuses faster which could be useful as well. However, I've seen enough decent shots from both lenses that I've just about come to the conclusion that neither lens will fail to perform in these situations if you get familiar with it. Right now, I'm leaning towards the 100-400, but haven't made up my mind yet... (Anything on my short list should be a marked improvement from my 70-300 IS at the long end where it gets a little soft.)

I would not consider the 2X TC to be an option. The lose of IQ and contrast are just not worth it. The 1.4X III and 70-200 f/2.8(any of them) is wonderful. No real fall off. However with a 2X on you are leaving a lot on the table. You also are adding more glass that was not designed to be there. When you are at a track while dealing with heat haze it can be made even worse.