Is 70-200 really the best option?
 

OK, after extensive research and donning my sheep costume, I now have (APS-C Crop factor in brackets)

Sigma 30mm F/1.4 (48mm)
Tokina 11-16 F/2.8 (17.7 - 25.6)
Canon 17-55 F/2.8 (27.2 - 88)

Last piece of the puzzle.

70-200 (112-320) leaves a gap between 88 to 112 (your going to tell me thats what my legs are for)

From what I can glean, ideally you want the 70-200 F/2.8 or F/4 WITH Image Stabilisation.

Are there any other lenses that make sense in this bracket?

You could always get a 24-70 2.8 Sigma or 28-75 2.8 tamron.

I would go with the 70-200 2.8, you could also put the Canon 2x extender for 640mm.

Are you considering the Image Stabilisation 2.8?

That seems quite a lot of overlap?

How about:-

Sigma 50-150 F2.8 (80-240)

or

Tokina 50-135 F2.8 (80-216)

James-The 70-200 2.8 just seems a HUGE amount of cash to spend. The thrifty Scotsman in me is insisting I consider the cheaper alternatives!

I own a Sigma APO 70-200mm F2.8 EX DG MACRO HSM, which I compared to the Canon 70-200 2.8 IS & 70-200 4.0 for a day before purchase.
Here is my take...
The Sigma is a little soft at f2.8, but then again so is the Canon.
The Sigma is also a little softer on the wallet than the canon.
The Sigma is a touch more stealth than the Canon... At some venues people see the white Canon L glass and refuse pro entry, or charge extra rates for bringing in pro gear.
More than 80% of the time I use a large zoom like this, it is mounted to a tripod or mono-pod where I would normally turn off IS. So in my case the Sigma made more sense than the Canon. The quality of all three lenses stopped down to f5.6 is comparable, and they all produce a good image. In the end though, the f4.0 was just too slow for what I do, and the Canon f2.8 was too expensive considering I would not need IS. So the Sigma was the right choice for me.

Buying Tip...

No matter which lens you choose, always test multiple examples of the same lens,
and choose the best example for purchase.

Good Luck!

Sorry, I misunderstood your question. I thought you were going to get a 70-200 and you wanted to fill that gap in between.

David, do you have any movie samples available to view from the sigma. Also have you tried a extender with this lens?

Sigma APO 70-200mm F2.8 EX DG MACRO HSM - £650
Canon EF 70-200mm f/2.8L USM - £1,049
Canon EF 70-200mm f/2.8L IS USM - £1,544

Looks tempting.

Ok, seen some stills from the sigma and the look very comparable to the canon.

Link: Flickr: The SIGMA APO 70-200mm f 2.8 EX DG HSM (Macro) Pool

Looks like version 2 of the lens is the one to go with. Also viewed some still shots with the x2 tele converter, they look ok. Would love to see some video with this.

I'm going to test one tomorrow.

James

Those are good alternatives for the crop factor of the 7D. I have the pre-Macro version of the Sigma 70-200/2.8, and it's very good. I've used the APO 2X TC on it for stills, but I would not recommend it.

Either one should be also cheaper than the Sigma 70-200/2.8 and much lighter/smaller too.

As for the difference btwn 55mm and 70mm. Can you really tell the difference?

I used to shoot with the 50mm and 70-200mm on 1.3x and 1.6x crop factor bodies, and no, I never noticed the difference. That short-telephoto range between 50mm and 70mm isn't very useful to me anyways - I nearly always used the 70-200mm at 135mm (which is why I later sold that lens for a 135/2L).

After testing the Sigma & Canon today I finally went with the Canon EF 70-200mm f/2.8L IS USM.

The Sigma was optically good but I thought the zoom and focus rings felt tight compared to the Canon. The feeling of the Sigma body coating also makes my teeth go, if you know what I mean.

The Sigma seemed faster on Ai. But as using mostly for video this did not seem a problem.

The IS is fantastic setting '2' does a great job when panning. I stood in the wind at 200mm and it handled it very well.

Tested a couple of copies they seemed identical. Also tested the x2 extender and for video looks great. Using on the 5Dmk2.

Initial tests look great, very happy but a little lighter in the wallet.

I suggest the 1.4 extender instead of the 2x. The 2x is really intended for Canon supertele primes. I have both of these TCs

THe canon 70-200 f4 IS is Canon's sharpest zoom