I haven't had a chance to try out the Canon 75-300 f/4-5.6 III USM, but I have the non-USM version which I picked up for ~$100 on ebay a couple months ago, which is optically equivalent. On a cropped body like the 550d, it has a great telephoto range, and is quite good in well lit areas. The USM version should focus a little faster and quieter, but I believe it is a bit heavier as well.

If you are hand-holding, the combination of the slow aperture and the need for a high shutter speed makes it hard to use unless the subject is well lit, however, when you are able to get the shot the results are quite good. There is some chromatic aberration, but for such a low cost that is to be expected, and there are ways to fix that in post-processing. Also, I highly recommend getting a lens hood, which is very helpful in midday sun.

Overall it's a decent lens, and at such a low cost it is a great option if you don't have a lens with a similar focal length.

I haven't had a chance to try out the Canon 75-300 f/4-5.6 III USM, but I have the non-USM version which I picked up for ~$100 on ebay a couple months ago, which is optically equivalent. On a cropped body like the 550d, it has a great telephoto range, and is quite good in well lit areas. The USM version should focus a little faster and quieter, but I believe it is a bit heavier as well.

If you are hand-holding, the combination of the slow aperture and the need for a high shutter speed makes it hard to use unless the subject is well lit, however, when you are able to get the shot the results are quite good. There is some chromatic aberration, but for such a low cost that is to be expected, and there are ways to fix that in post-processing. Also, I highly recommend getting a lens hood, which is very helpful in midday sun.

Overall it's a decent lens, and at such a low cost it is a great option if you don't have a lens with a similar focal length.

I am going to assume for this post that you are referring to the Canon 75-300 f/4-5.6 III USM.

I have the non-USM version which I picked up for ~$100 a couple months ago, which is optically equivalent. On a cropped body like the 550d, it has a great telephoto range, and is quite good in well lit areas.

If you are hand-holding, the combination of the slow aperture and the need for a high shutter speed makes it hard to use unless the subject is well lit, however, when you are able to get the shot the results are quite good. There is some chromatic aberration, but for such a low cost that is to be expected, and there are ways to fix that in post-processing. Also, I highly recommend getting a lens hood, which is very helpful in midday sun.

Overall it's a decent lens, and at such a low cost it is a great option if you don't have a lens with a similar focal length.

I haven't had a chance to try out the Canon 75-300 f/4-5.6 III USM, but I have the non-USM version which I picked up for ~$100 on ebay a couple months ago, which is optically equivalent. On a cropped body like the 550d, it has a great telephoto range, and is quite good in well lit areas. The USM version should focus a little faster and quieter, but I believe it is a bit heavier as well.

If you are hand-holding, the combination of the slow aperture and the need for a high shutter speed makes it hard to use unless the subject is well lit, however, when you are able to get the shot the results are quite good. There is some chromatic aberration, but for such a low cost that is to be expected, and there are ways to fix that in post-processing. Also, I highly recommend getting a lens hood, which is very helpful in midday sun.

Overall it's a decent lens, and at such a low cost it is a great option if you don't have a lens with a similar focal length.