There are many places where one could find used and refurbished Canon lenses for sale. The best places to look for used Canon lenses would be on Amazon.
No, a Canon lens cannot be used on a Nikon camera because they have different lens mounts and are not compatible with each other.
A Canon L Lens is in the line of SLR photography lenses made by Canon. L lenses are Canon's top lenses and according to Canon's Lens Work III Book L is for luxury. They are used on cameras for better zoom and image quality.
A 58mm lens hood is used with a Canon camera to reduce lens flare and improve image quality by blocking stray light from entering the lens.
Canon has long been a respected name in the camera and photocopy business. The Canon EF 100-400mm is a telephoto lens that can be used online from Amazon and eBay.
I have used a 80 - 200 F3.5 Tamron zoom on my Canon A1 almost exclusively for 35mm with great results. It's not a Canon lens as you specified, but I thought that might help anyway.
Canon telephoto lenses are a basic standard type of lens that magnifies the subject buy a certain percentage. Different lens are used in different settings- sunny, farther subjects, and in the snow.
EF and EF-S lenses can be used on 400d. There is a lot of lenses out there.
A Canon teleconverter is used to extend the reach of your camera's zoom lens. The Canon teleconverter will let one zoom out a bit farther to get a closer picture of his subject. It's also used for saving money because a Canon teleconverter is a little cheaper than getting a brand new, more powerful zoom lens.
No, Canon lenses cannot be used on Nikon cameras because they have different lens mounts and are not compatible with each other.
Yes, they have common E-FS bayonet.
You can use websites such as the online store Amazon or eBay to list your Canon cameras for sale. In addition, you can list your Canon cameras for sale in Craigslist.
The Powershot models will work fine for her and are affordable new, but you might find a good used Canon for sale in your local classified ads, local photo stores, or you might consider older models on clearance or refurbished at Canon's website, ebay or the discount online store, Overstock.com.