I am hoping to get a wide angle lens next spring/summer, and I think I'd prefer a prime lens (although I'm open to suggestion). I have the Canon 40mm pancake now and I love it, but I'd like something wider since I have crop sensor bodies and I don't get the full effect of 40mm. Not a lot of $$ to spare - so not an L lens for me - but I would like something that will work well in low light. This will be used for landscape only and I want as little barrel distortion as possible, as I don't have software to correct it. I'm hoping to stay under, say, a $650 budget? Is that reasonable? I've bought rental lenses before and had no problem so used is fine (and will help keep it affordable for me). I have a mix of Canon and Sigma lenses now and I've been very happy with Sigma - so non-Canon is fine too. What do you suggest? I think a 28mm translates to approx. a 44mm on my 50D and 60D bodies- do you think that would be wide enough to let me take broader landscapes and not have much distortion? Many thanks in advance for any opinions!