Both movies are about young photographers obtaining cursed/haunted cameras. Shutter is more creative with its plot whereas SLR uses more CGI.
They have a similar theme and videos/photos as an important plot element...I would say more but it would be a spoiler, watch them both and you'll understand. ;)
Banjong Pisanthanakun and Parkpoom Wongpoom directed both films. Both films also have a twist ending.
