So, my current telephoto lens for my T1i is a Vivitar Series 1 70-210mm lens. Fun fact #1 - It was $20. Fun fact #2 - It's a Pentax-K mount, and I currently use an adapter. Fun fact #3 - It does an awful job with reflective/brightly lit surfaces. When a surface is lit from behind, even with fairly diffused lighting, there is horrendous purple fringing, as show in the photo below. Sorry about how out-of-focus it is, my hands weren't all that steady and the focus screen on my T1i is having some issues.
(click for link)
It also lacks autofocus, which isn't a big deal, except that I'd like to use it for sports, where I can't always focus fast enough.
I've done a bit of reading, and decided that I might spring for the Canon 70-200mm f/4L
I've decided this based on reading about how poor the EF 75-300mm
is, and by wanting to go with an EF mount lens, as I'll probably try to go FF with my next camera purchase, though that likely won't be for a while. According to Amazon, the 70-200 f4/L is only ~$60 more than the 70-300 f/4-5.6 IS USM, which is worth it to me for the difference in image quality.
Unfortunately, I'm not really in the know about 3rd-party lenses (Sigma, Tamron, et. al.), and since this is a pretty big decision, I'd like to get a bit more input first.
If others think my choice is appropriate, how much do you think I'd regret not paying for the IS version. Obviously I was a bit shaky on the above shot, though I really should have grabbed my monopod, but to save $600, I think I could manage to carry my monopod or tripod with me more often.
I'll try and test the best options before I buy, but I'd like to narrow the field a bit first.
I'll be able to report how this lens handles on a film camera soon; just need to finish up my first roll of film there and get it developed.
EDIT - As noted by JAE, I got my Canon lenses confused. I've fixed that in my post but wanted to give some context for his response, as it was quite handy.