Forget Vivitar. Buy the Canon lens. There is no such thing as a good, long, cheap zoom lens. The best you can hope for is a decent, not-quite-long-enough, affordable lens. If you want a longer lens, look for a used Sigma 400/5.6 APO. I know of one in mint condition which just sold for $300. All the long (300mm+) zooms are soft at the long end wide open, which is where you will be using the lens for wildlife 99% of the time. Oh, and whatever lens you have, it won't be long enough (or fast enough)!

If you shoot print film and rarely enlarge past 4x6, and your standards aren't too high, then almost any of the long telephoto zooms (100-400 and thereabouts) will probably be good enough to give you images that you will be happy (or at least not unhappy) with. print stickers | sticker printing | printing services | business printing