A common type of photography forum question asks “What lens(es) should I get?” or “What is/are the ‘best’ lens(es)?” It is really impossible to offer the type of answer that the poster is looking for without asking for a lot more detail. Here is a slightly edited version of a reply that I recently offered in response to such a question:

There is not a single “right” answer to most questions like this. Choice of lenses is a very personal thing and factors that affect one’s choice of “best” include: budget, future plans, type(s) of photography, zoom/prime preference, preference for many/few lenses, whether the end product will be electronic sharing or prints, how large the images will be, etc.

Without knowing a lot more about your photography and your preferences, most responses will be along the lines of “here is what I like for my photography” or “no idea, really, but here are some general guidelines that might work.”

With that in mind, here are a few general guidelines:

• For landscape one probably wants wide angle – at least 17mm on a crop body – and doesn’t need large apertures as much since typical work is often done stopped down. Fewer and/or smaller/lighter lenses may be good if one works a lot on foot.
• For sports/action photography one generally may want longer lenses, and larger apertures could be important for low light (e.g. indoors or at night) or permitting slightly faster shutter speeds. Image stabilization could be less important here, and for really long focal lengths primes may be a good choice compared to zooms, but it is hard to generalize.
• For street photography, many prefer to use a small body with a prime or two, though others like to work with a single zoom. Many like wider but not ultra-wide lengths and some like somewhat wider apertures. On the other hand, there is a contingent that likes to use longer lenses and shoot from a distance rather then getting “up close and personal” with the subject.
• For portraits, many like wide aperture primes in the 50mm to 100mm focal length range (on crop bodies), though some also like zooms that cover this range.

Trying to make one or a few lenses cover all or a good part of this range of uses will require some compromises and/or very deep pockets.

For general use, a lot depends on stuff like budget. The 17-55mm f/2.8 IS is a high quality choice for Canon crop bodies; the 18-55mm kit lens is a good starting point if you don’t really know what you want; the IS version of the latter lens is reportedly fairly sharp and is a great value.