I have just been given an old canon EOS 500 not digital. with this were 2 lenses one being a canon28-80mm the other is a sigma70-300mm. As I'm looking at getting a SLR camera in the future I was wondering if these are decent lenses and what magnification the larger lense gives. I'm hoping these can save me some money(credit crunch and all that). Forgive the ignorance as I have only obtained the photography bug in the last 2 or so years.