FS7: FS7/A7s Question about Exposure

1

1027Films

Well-known member
Hey guys!

I have a shoot in the next few days and I had some quick but important questions. I was wondering if that when you are shooting with the Sony FS7 in Slog-2 or 3, should you do the 2 stops over-exposed process that is recommended with the A7s?

Also, when shooting with the FS7 and A7s, how can you actually tell when its 2 stops over (properly, not blowing out anything)? This is probably such a newbie question, but I've never used a camera that required extreme over exposure when shooting. I've seen people shoot with the a7s in Slog 2 with the screen almost completely white and blown out, and then it comes down beautifully in post, but that makes me extremely nervous! haha

Anyway, I appreciate any help!

Thanks!
 
,On the FS7 I would definitely recommend slog3/s-gamut3.cine because it's easier to grade to your final desired look. You can only access this combination in CineEI mode (not custom mode). Fortunately for you the FS7 in CineEI mode manages overexposure for you very easily by letting you overexpose what's being recorded but actually see the image look "normally" exposed in your viewfinder or monitor (if you turn that on for your VF or monitor).

So for example in CineEI mode you set the camera to 1000 ISO but in reality it's always recording at it's native ISO of 2000. That means you're exposing the scenes "as if" the camera was set to 1000 ISO but since it's actually 2000 ISO (more sensitive) you are overexposing by 1 stop. Set the ISO to 500 ISO and now you are overexposing by 2 stops. It's that easy - and again it looks "normal" in your viewfinder or monitor.

As for the A7s, it's a pretty clean camera but if you overexpose by 1-2 stops then you can improve the noise in areas of the image the same as the FS7. There's no built in tool for handling overexposure so you have to overexpose it yourself. No big deal here's how you do it. Put a 1 stop ND filter on your lens and setup your exposure to normal and proper levels. Now take the ND filter off, don't change your exposure, and press record. You are now recording 1 stop over exposed. Sure it's pain in ass, but it works.

Last tip, for each stop of overexposure you do on the camera you improve the signal-to-noise ratio of the camera by 3db. So 2 stops is 6db improvement. This works good for green screen work, or as I have found if the scene has large areas of dark tones. You will have way less noise in those shadows plus have decent detail there. Again, all of this comes at the expense of losing some of your range in the high end.

Here's a good video showing some noise differences on the A7s when exposing normally vs overexposing:

https://vimeo.com/100562117
 
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