Canon 70-300 IS USM Vs Sigma 100-300

[rob13]

I'm looking to buy a telephoto lens for UK motorsport this month, in prep for the start of the superbikes season and for my trip to Oulton next month.

I've got a budget of about £400-450 so its pretty tight for a telephoto. I appreciate that new, the 100-300 is above my budget but has anyone seen 2nd hand ones changing hands for about the £450 mark?

I know the Sigma is generally regarded as the better option but has anyone got any shots taken with the Canon 70-300? I'm using a 40d body.

[micloi]

You can get the 100-300 non-dg used within your budget and I would suggest it over the Canon as it is sharper at 300mm, faster (f4) and takes the 1.4xTC with very little use of IQ making it a nice 420mm lens. You won't have IS but at 300mm with an f4 you won't miss it IMHO.

[mipevo6]

My 70-300 always gets used for wildlife, but quite a few examples on my flickr page

my flickr page (http://www.flickr.com/photos/mipevo6/)

or check out the 70-300 flickr group...

here (http://www.flickr.com/groups/canon70300is/)

Can't comment on the sigma...

[Robbo]

I have just got the canon lens, if you look here http://www.slrgear.com/reviews/showproduct.php/product/253/cat/11

you can see how good the lens is and especially for the price. has USM and IS and between 70-250 is very sharp, and only a lil bit softer at 300mm