It's National Camera Day and what better way to celebrate that than by launching new cameras. Or so says Canon. Although these two new DSLRs won't be available for purchase until late next month, they have been years in tha making. So what's a few more weeks' wait? The new EOS 6D Mark II and the new EOS Rebel SL2 give budding and slightly advanced photographers almost everything they can want from a serious camera. All except for one now common feature: 4K video recording.