I use the T2i, and I primarily use the 18-135 lens, which is fantastic. Never used the 75-300 but from what I've heard it's a great lens.
Only thing I'd look out for is not being able to take any close up shots if you go for the 75-300. What I mean is that with the 50mm fixed lens and the 75-300 mm the lowest zoom you can get to is 50mm without being able to change the zoom. With the 50mm you already have to stand fairly far back to take a photo with your whole subject in the frame, and that would only be worse with the 75-300. That makes taking photos in tight spaces a real pain.
If having that 300mm of zoom isn't vital for you I'd def consider the 18-135, very versatile. Good for everything and takes great photos.
As far as the fish eye goes, I'm not too versed with them. Sorry.
Im going to be taking pics of cars and parts mostly so I think that lens will be good for me. I'll look at the zoom lens later in the year if I think I need it for racing pics. Thanks for your recommendations and advice guys.
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