You need a HEX, for carrying the payload of a DSLR and the safety of it, if there is a fault with a prop, motor or ESC on a quad it just falls out of the sky, with a hexacopter it will stay up and be landable,
DJI NAZA is a good choice for a newbie and suits aerial photography use, if you can afford it the DJI A2 is even better, very stable and used by professional aerial photographers.
Size wise, start with something at least a 550mm but depending on camera weight you might need to go up to something bigger like a Tarot 680/690
Motors ?? six of DYS BE2812 880KV should give you the weight/power/payload balance you need but run your proposals through https://www.ecalc.ch/xcoptercalc.php before spending any money.
For a bigger motor I use EMAX MT3515-650
Hope this helps