I'm more inclined to sway towards Canon than Sigma Andy..... snobbery I guess! Like I wouldnt park a KIA on my driveway(or in my road!) when I had one as a company car for a few weeks in 2008!

As its cricket I'm swaying towards, finding examples of of specifically that using this equipment is tricky. Ive found examples using the 100-400 but not the 70-200 2.8 with a x2 tc....

Ian, I only have the one camera at the moment so a prime would be impractical in as much as any play happening towards me i.e. fielding would be missed and when I do decided to (which I'm sure I will!) shoot football, rugby?, motorsport to an extent, and other subjects like days out at the zoo or what not (just general stuff) I would be too limited.

I will consider a prime when I buy myself a 1d of some sort (mk3 or 4) to mount it on, keeping my 550d as a second camera with a 70-200 I expect... but this may be a while!

70-200 IS is a great lens but you'll introduce some compromises using it with a TC.

You not consider a prime? 300 f4 is comparable money wise to a 70-200 2.8.

Also - I wouldn't worry about the aperture or IS outdoors, shouldn't ever have a lack of light. Wider DOF at narrower apertures may be more useful to you in practice.

I'm not a Canon man so forgive me if the information is wrong, after a quick search it doesn't look like the 70-300 is compatible with CANON teleconverters, however it is with the Kenko ones, which do get some alright reviews.

Obviously the highest form of quality would be the 70-200 with the Canon TCs but at what cost? The quality would be speculative, have a read of some reviews and see some sample images (i always search flickr for end user shots with the equipment i want to use, not lab shots etc)

If you need longer than 300mm, you could always look at the Sigma lenses, they do a 150-500 and 50-500, both with OS but again i don't know if the quality of those will be sufficient for you.

Oh, and I don't think the 70-300 is tc compatible...

I need a tele zoom lens, gave my kit one away, 70-300 and need to replace it. I found that 300 wasn't quite enough for cricket to not need lots of cropping due to the boundary distance from the wicket so....

I've been thinking on getting the Canon 100-400 lens but am put off by the push/pull zoom mechanism and the somewhat slow f4.5 - 5.6.

The only other options I would consider are a 70-200 2.8 IS or 70-300 4.5 - 5.6 IS with either a x1.4 or x2.0 tc. Down sides are the slower apertures with a teleconvertor and I've read a fair bit about AF slowing right up and loss of image quality. Plus the extra cost obviously of going down the lens + tc route, especially seeing as the 70-200 is a fair bit dearer to begin with.....

Also going to get a 50mm prime f1.4 and external flash, thinking 480ex as the built in one on the 550d has its limitations for me now!

Any advice / opinions on the tele lens quandary? Want to get this order by Wednesday really...