Low Light: Gain vs. Shutter Speed vs. Levels in post?

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digexpressions

Active member
I shoot a lot of low light weddings. Obviously, the first thing to do when things get a little dark is to open the iris and turn on the lights. Many times, this isn't enough to get proper exposure. So what should be done next that will result in the cleanest final image?

1. bump the gain up
2. lower the shutter speed
3. leave it and boost the levels in post

A bit about my settings: I like to shoot 720/60p (I tend to use a lot of slo-mo) with a shutter speed of 1/60. I render out to 30p to get away from the "video" look. Would using a 1/30 shutter speed mess things up since I'll be taking frames away in the final step?

Also, anybody using 18 gain?
 
I had to use +18 gain when I was shooting a wedding in DC and they went to a museum and I wasn't allowed to use any lights. It was grainy as hell but it was the only way I could get any kind of shot. You could go to +9 and that should be ok. If there's not a lot of movement try lowering the shutter speed. That won't give you noise but it will give you motion blur. I've never tried to boost a shot that low in post. You'll get something out of it but it all depends on how much info you have at the beginning.
 
Lowering the shutter speed will avoid grain the most, but it will also add blur to the image. So your choice is: would you rather have grainier footage, or blurrier footage? Adding gain will add grain but not blur; slowing the shutter speed will add blur but not grain.
 
But about your question using 1/30 for 60p... I suspect it would be similar to 30p and 1/30 shutter if converted to 30p... but the shutter would be open 2 frames which would not make for as good slow mo...

Why wouldn't you just shoot 30p then? should get a tad more light from what I have experienced. I use +6 and +12 when needed... but I would fight to add off camera LED lights to whatever I was shooting...
 
60p @ 1/30 would look exactly the same as 30p @ 1/30. You can't have a shutter speed that's slower than the frame rate; the camcorder will have to go into frame-doubling mode.
 
And your frame rate will be 10 fps, each frame 1/10th of a second apart from the other.

Again, it is impossible to have a shutter speed slower than your frame rate. If you try, the camera will adjust the frame rate down.
 
It doesn't do that on any cameras I have used (HC1, HMC40, HF10). They all produce normal framerate clips (60i, 30p or whatever), with repeated frames at whatever shutter speed was specified. A buffer accumulates the exposure, doles that image out to the required number of repeat frames, then the buffer refills.
 
The recorded rate is still 60i or 30p etc, but the actual frame rate you get (i.e., the number of discrete frames per second) is dropped. It gets dropped through frame duplication, so if you go to 1/30, you will have no more than 30 unique frames per second -- even if it records sixty.

It is impossible to hold the shutter open longer than the frame rate. Therefore the frame rate must drop to allow for the slower shutter speed. Go to 1/6, you'll find that you have six distinct frames per second. Go to 1/4, you'll see that there are no more than 4 frames per second. Each one will be duplicated 15 times, but there are four distinct frames per second.
 
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