Shooting in low light is a very common question, and often people will respond “just use lights!” Yet there are also valid reasons to seek out a camera body which is excellent at low light instead, such as shooting a documentary or you are using lights already but want to keep your lighting kit minimal (to list just a couple of the reasons). So which to go for?
Obviously the best option would be an A7s, as it as downright insanely good low light capabilities! As this video filmed out in the countryside with only moonlight demonstrates:
But for many people this camera is complete overkill! You want good low light, but don’t need it to be *that* good! And as one of the most pricey mirrorless cameras, you’d like something cheaper. Which to go for?
Go for a Sony A5100 (I got mine for a mere US$310 like new from Amazon some months back. Go for the A6000 though instead if overheating could be a serious concern you wish to avoid) plus a focal reducer (another hundred bucks) plus a Nikkor 50mm f/1.2 (which would be a few hundred dollars second hand). Won’t be as good as an A7s of course, but is the next best thing on a budget!
A5100 is the A6000 but with XAVCs added in as a bonus, and at a cheaper price too!
http://www.eoshd.com/2014/04/surprise-sony-alpha-a6000-video-mode-huge-improvement/
And the A6000 is the D5200 (they share the same sensor), but with a mirrorless mount and more features. Which allows you to double the light with use of a focal reducer! And the D5200 already compares very favourably vs the Canon 5Dmk3 (which was the former “King of Low Light” before the Sony A7s came along and crushed it). You can see how the Nikon D5200 performs at ISO 6400 and even 12800:
http://www.eoshd.com/2013/02/nikon-d5200-vs-canon-5d-mark-iii/
And the A5100 is a two steps ahead from the D5200 in terms of features/performance. A bargain low light filmmaking machine indeed!
http://www.eoshd.com/2013/02/nikon-d5200-review/