There are couple of options to view raw footage already, but i think you should check out one of the most intresting solution.

I don't know if this viewer was already spotted on this forum (quick search revealed nothing). AFAIK it is made by couple of independent software engeneers and by this moment it is free.
I think this player is hugely underestimated (its initial group on "russian facebook" has only 50 members, don't know about actual facebook), full list of its features is compelling. Here is a couple of them:

This is GPU-based software designed to perform postproduction in real-time or faster
Now you can ingest your CinemaDNG footage from SSD, do all image processing on NVIDIA GPU and play 4K video smoothly on monitor in realtime
No delay: you can check quality with full-size resolution right after shooting the scene
Realtime denoising on GPU is default feature
Playback of folders with sequences of DNG/CinemaDNG files
Fast and efficient cutting and trimming of your footage before color grading
Realtime color grading with 3D LUT

So this is great for fast preview of you footage on set even with an average laptop with proper cuda card.
It is not an advertising, i just feel sorrow for these guys who became feedback on their product just from couple of comments in social network.

By the way, for those who are afraid of "vague" programs and websites, there is an article on 4kshooters about this viewer: