Hey there, I have a d70 on its way to my house and im looking for a couple other lenses to add besides the kit 18-70 dx. Are sigma lenses decent quality? How about this... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3343&item=3835122196&rd=1#ebayphotohosting Is this lens a joke? Or will it take good photos? Any help would be great.