Result maybe in less digital appearance of some pictures.
Part of what Michat refers to as a "digital appearance" might be the lack of foreground - middleground - background separation in pretty much the entire "Clíodhna - the witch of Gleann an Phéine" teaser, due to closed aperture/large f-stop number. For example, at 0:21 a guy is walking away from a line of trees. The interesting thing is the guy, so he should be in focus, and the background trees should be out of focus. Or at 0:58, where there's a guy in the foreground really close to the camera, a girl speaking in the middle, and trees in the back, all of which pretty much fully in focus. In a professional video production, at least one of these would be out-of-focus to draw your attention to the important part of the scene.
To get this effect, obviously you either need somewhat expensive equipment, namely something like a 200mm f/1.8 lens, or do a ton of post-processing, probably using sophisticated aka. expensive video software. I understand that neither of which might be feasible.