I currently shoot with a Canon 450D and i am looking to purchase a wide angle zoom to use when taking landscape photographs along with the odd interior picture fir a friends holiday let website.
sjh
Hi there sjh and welcome to the Q&A Forum,
There are several options to choose from, limited only by your pocketbook.
I suggest you take a look at the Lens Rental site listed below. I've found it very helpful in learning about available lenses. I actually rented a lens from them and plan to rent more; some of the lenses I'm interested in aren't available locally. Beside, lenses can be very expensive and I prefer to rent first to see if I really like it. It's less costly than buying a lens and possibly having to pay a restocking fee it I don't.
http://www.lensrentals.com/category/wide-angle/for-canonAs you probably know, the XSi has a focal lens multiplier of 1.6, so keep that in mind when deciding which lens will best meet your need.
Related reading: focal length multiplier
http://www.digicamhelp.com/camera-logs/dslr-dilemma/focal-length-multiplier/
