Boog,
Just wanted to chime in and perhaps share my experience with some of the 70-200 lenses available on the market at this very moment:
1. If money is not an issue and budget is accomodative, I would suggest to look long and hard at Canon 70-200 F2.8 II L lens as it is no doubt the best 70-200 EF mount L quality lens money can by at the moment.
2. for folks on limited budget or not using the lens enough to justify the option #1, or not needing F4 aperture ever (say, studio shooters - Tony Corbell) - Canon 70-200 F4 L might be the right lens. ( Personally, I do not like the bokeh of the lens but that is just me).
3. For folks that would like to have _ALL_ the functionality of the Canon 70-200 F2.8 II L lens but cannot afford or justify paying premium dollars for it, I would recommend to see if the Tamron 70-200 F2.8 VC USD fits their requirements.
I am personaly in the category #3 ( I cannot afford the best of the best so have to be smart about spending my money

). I used the Tamron lens extensively over last 1.5 years and so far very happy with IQ, AF quality, bokeh characteristics of the lens. The lens never let me down in low light conditions, locked swiftly (almost as fast as the Canon competitors) on fast moving subject and in difficult conditions ( say, focusing through the wire mesh on the fast moving subject about 20 meters away behind the mesh). I bought the lens brand new ( open box deal) from an Authorised Tamron reseller in Melbourne with full 24 month warranty included for A$950.00 - that's approx. US$750.00 . Speaking from my experience with the lens: The lens is sharp, very sharp up to 160mm FL and then just sharp there after

at 200mm not as sharp as Canon F2.8 but difference is really minor. I would hazard the statement that at @135mm Tamron is even better than Canon F2.8 at the same focal length. and did I mentioned reliable AF performance?

Happy to share some of the photos I have taken with the Tamron lens. Send me a message if interested.
Dustin Abbot owns the Tamron lens and used it professionally. I am sure he will be happy to address your query regarding the qualities of the lens.
And finally, few words about the Sigma 70-200 EX DG OS USM:
well, the lens is not up to speed with the other 3 options... across the board.. That said Lindsay Adler previously used the lens extensively and produced stunning award winning images with the lens. I would personally avoid purchasing the Sigma 70-200 EX DG OS USM lens as I had _major_ AF and reliability issue with my copy. I had to return ther lens in 2 weeks time as my experience with it was unbearable. It did not cut the mustard for me. at all..
boogaloo said:
Hi folks
Looking for the benefit of your wisdom. I'm fairly sure I read a while ago that Sigma were planning to update their current 70-200 f2.8 lens, and I believe Canon are also working one a new one. I do a fair bit of sports photography (very amateurish) and currently use either my 130mm portrait lens or my 70-300L when doing action shots.
I'd absolutely love the 70-200L IS f2.8 canon but it's an enormous amount of money for me to spend. I also think I read somewhere that this lens is due to be updated fairly soon and would be gutted if I dropped the cash then it was refreshed.
I hear decent things about the Sigma 70-200 EX DG OS USM but again I am fairly sure I read that they're releasing a new version of this.
I know Tamron also do a similar lens but know less about that.
Bad time to buy a 70-200mm if I can wait 6 months? What would you do I my position? All views very welcome.
Boog