Use an Amex for warranty, and use the best portal you can find (Befrugal for Adorama?). Not worth giving up the extra year of Amex warranty for an extra % here or there. 5% vs 1%/1 MR per $, then maybe worth considering.

People may say "sign up for a new card and get xx,000 miles for your purchase" but that makes no sense unless you couldn't achieve the sign up spend with your regular spend pattern AND you're averse to MS. What's the camera cost? $1000? It costs $12 at most to MS that, so just put large purchases on the best card you have and MS when necessary.