Thank you for sending me the site. Still says it is invalid number. I think it may be because I bought through Hong Kong. But I did get a chance to register the camera and its number on the Canon site, so maybe Canon will get back to me. --Joan

I entered my serial number numerous times and each time got an 'invalid serial number'. Has anyone else had this problem?

Thanks Snowbear. I am so glad you responded. You have cut through my confusion very nicely.

I'm debating getting a Nikon d5100 or a Canon T3i. My Dad, who used to shoot architecture professionally using Nikons (pre DSLR) has a lot of old lenses he might give me. He does not have any old Canon lenses. How useful would these old lenses be? How easy are they to use on a Nikon d5100? How is the crop factor effected and how easy is it to guess what the frame of the picture is actually going to be? So I guess I am really asking, all other things being equal, should my choice of a new DSLR be weighed toward the Nikon just because I have access to old lenses?

I've been lurking for a while and it's time to say hello. I'm a total beginner with only a Canon Powershot S50. I am very interested in stock photography so I recently purchased Lightroom 4 and Elements 10. It's all very overwhelming so UH is very helpful.