The EF 24-105mm f/4L IS USM is probably the favorite "working" zoom lens (general purpose lens that you can just leave on the camera for most shooting needs.)
The EF 75-300mm is an entry level lens -- it's intended to be an affordable lens, but all the other zooms that cover a similar range to the 75-300 outperform it. (There's an EF 70-300mm f/4-5.6 IS USM which is much better and several "L" series lenses which are even better still.)
Canon's best glass is their "L" series line. The lenses have the suffix "L" written after the focal length (or focal length range if it's a variable focal ratio lens). They also have a red stripe around the front of the glass which makes them easy to recognize.
There are also lower cost options than the 24-105mm "L" series lens... such as the EF 28-135mm f/3.5-5.6 IS USM, but I"ve always felt that the 24-105 L glass is a great deal. Considering it's high end quality, it's actually one of the most affordable high-end lenses in the line-up (most L series lenses are over $1000 and while the 24-105 lists for $999 you can commonly find "white box" versions of it for around $650. A "white box" lens usually means the store had a full-frame camera with kit lens... such as a 5D III with 24-105mm lens (the "kit" lens when you buy a 5D III with lens) but the buyer didn't the want the lens and the store didn't have a "body only" version of the camera in stock. So they remove the lens, sell the camera to the customer, and then sell the lens (which is technically "new" even though it's not in retail packaging) and you get a new lens for about 1/3rd off the "new" price.
Tim Campbell
5D III, 5D IV, 60Da
