View Full Version : Shutter Speed and Grain Woes...
12-07-2006, 02:51 PM
So now that we're ready to dig into the advanced settings of the A1, I'm curious to better understand shutter speeds. I just don't quite understand how they make a difference to picture, and how to choose the appropriate one for the appropriate scene or look. For isntance I've been more than satisfied with our night time footage so far, except for the low light instances. I've seen some great footage in this area (ncje's Ginza footage for example) but I can't escape serious grain when shooting in even slightly dark areas. Granted the only adjustment I've made so far is to put it in 24p, so I'm really curious as to what else I can do to improve the footage.
If there's some general info or tutorial on shutter speeds I've overlooked, please feel free to link me to it. Otherwise, I'd love some A1-specific info if any of you can share. Big ups.
12-07-2006, 05:10 PM
Shutter speeds are the time that the sensor (or sensors in this case) is (are) exposed to what ever you are pointing the camera at. You will let more light in with lower shutter speeds, and your image will be brighter. But if you have lower shutter speed, you will have a blurrier image due to the sensors being exposed to the light while anything in the frame is moving at a significant speed, meaning it picks up the movement within one frame and is blurred. Higher shutter speeds at lower frame rates will result in choppier footage and lower shutter speeds will be more fluid.
12-07-2006, 08:31 PM
Try to shoot with -3 db, 24F and a 1/48 shutter.
Whatever you do make sure you put it in manual mode and try some tweaks. With auto mode (the A on the wheel) engaged the camera will gain up quite a bit in lowlight.
Also, if you're expecting the camera to see in the dark without any noise at all, I'm afraid that's just a bit unrealisitic.
12-07-2006, 08:39 PM
What other effects does -3 gain have other than making the sensors less sensitive to light? Does it further reduce noise? Right now my gain switch is programmed at -3, 0, +3.
I have left my shutter speed at 1/48th, 24F. I use my iris to include what I want to be or not be in focus and use the ND filters and gain switch to get the exposure where I need it. Really, I am between -3 and o gain. I am looking for differences now...
12-07-2006, 08:57 PM
-3dB is the lowest noise mode, at least without resorting to any of the NR functions. It reduces noise slightly over 0 and +3 dB as one would expect, but the difference visually is slight.
12-07-2006, 11:15 PM
Gracias para la informacion.
Might I also ask how the Gamma Curves (CineGamma, right?) play into the situation?
And while we're on the subject of the setting wheel, what do all those modes mean? I get Manual and Auto, but the others I'm not familiar with and I couldn't find their meanings in the manual.
12-08-2006, 07:32 AM
What is the ISO of the sensors at -3db? I think I read that at +18db it's ISO 800.