Telephoto lenses... any good alternatives to Canon?

I currently have a 75-300mm USM IS canon lens that I use for telephoto stuff (birds usually) but i have decided I need more zoom than that. I need about 400-500mm i think. I know the other brands such as Sigma make zoom lenses too, but what is the quality like? I just cant afford to spend thousands of dollars on an L Lens.... But i would really like to get some decent sharp close-ups.

Thanks!

The only alternativce to Canon's big primes come from Sigma..
There zooms are also real competitors,. in some cases (ie the 300mm zooms) outshining anything that Canon makes in that focal range (in a zoom)

Also there is the Tamon 200-500mm,. but we hear very little about it,. no idea of the quality either compared to Canon or Sigma.

But.. as soon as you go into the 400mm - 500mm range,. you are going to spend over $1K no matter what., so why not look at the Canon 400mm f/5.6 prime. That is a real birding lens.

I agree with CDS, even such bargain super zooms as the Sigma 50-500mm (Bigma) cost about $900~. The 100-400mm Canon runs $1400~.

You may be able to use a Sigma 135-400mm or a 170-500mm Both are sub $600 lenses. However, I'm not sure of the optical sharpness for either, but they may fit your budget needs. I'm sure they must be as sharp as the 75-300 IS at the 300mm end. But you will give up IS.

I'm pretty stoked with the Tamron 200-500mm. If you do a search on the forums here you will find the odd review. Plus the feedback at FM has been good as well.

Plenty of fans of the Bigma about the place as well.

you can get a sigma 50-500 for around 720$ used or ~$800 new.
Lot less than $1k and gets sharper as you get closer to 500mm. I have owned 2 and own 1 now.

still not stoppin me from gettin a 300 2.8 IS and 1.4tc

Yupe, i got my Bigma used and i love it.

I can't say much about the Tamron 200-500 as I've not had a chance to try one out but I am hearing that the people using it are happy. Pricing isn't very good on it over here though. The Sigma 50-500EX-DG is quite a good lens (my personal choice) and of very good optical quality (very close to the 100-400L for IQ) and build. It does take some practice to get the most out of it, but thats the same for most things.

If you want a prime it's very hard to go past the EF400 5.6 that CDS talked of, it's a very sharp and one of the faster focusing lenses about. Very popular for birding, little more than the Sigma/Tamron zoom but not a huge price tag on it. Only catch with all of this range of lenses is they eat up light, feed them well and they should reward you nicely.