AC130: Panasonic AG AC 130 - Getting a great image / Grainy footage

tokun1

tokun1

Well-known member
Hello Forum,

Not sure why my footage always seems a bit grainy. When I shoot in 1080 24p on my Panasonic AG 130, I open the clip after it's shot, and it always seems just a bit grainy, almost like I added gain, even thought I didn't, and there is plenty of light where I'm shooting or I add light.. Is there something in the settings to get a more crisp colorful, less grainy image to recommend, am I doing something wrong? I'm not sure, but. The DSLRS blow this camera away, and cheap DSLRS too.

Thanks very much for help!
 
Sounds like maybe two issues in play against you here. I'm guessing that while shooting, the image quality in the viewfinder is looking acceptable to you. Maybe you need to try using an external monitor and see if that helps by showing the grain that you aren't seeing during the recording. Secondly, you might have something in your settings that is not best for what you're shooting, exposure-wise. If you can go into a manual exposure mode, then I recommend trying that. Set your aperture/iris to as wide as possible to get maximum light to the sensor. Next, adjust your shutter speed. Start with the 180 degree rule; which means to set it at double the frame rate. Shooting at 24p? then set the shutter to 1/48 (or as close to that as your camera can, depending on what shutter speeds it offers). Next, check the gain value. For this older camera, older sensor technology (I'm guessing), you probably want to stay in the area of -3dB, 0dB, or +3dB. -3 should give you about the cleanest image you can get. But if that gives too dark an exposure, then start increasing it. Once you hit +6dB, I imagine you will start to get some grain. If you haven't done so already, you need to do these kinds of tests with any camera you are not familiar with, to find it's limitations and then you will know how much gain you can add, and then also you need to find out how much grain you can tolerate. It's a balancing act when you are trying to deal with too much grain. If you have motion in your scene that is too fast for a slow shutter speed, then you will get a blurring of the image. But if the motion is low enough, then you can break the 180 degree rule and start to slow down the shutter speed to get more light on the sensor. So, if shooting 24p, experiment with moving the shutter speed somewhere between 1/48 and 1/15. As I recall, I found any scene with ANY motion to turn out blurry if I went slower than 1/15.

Not trying to school you here, but just to go one bit deeper in this subject.... Grain is caused by too much gain. When your camera's gain goes up, it is just cranking up the voltage going to the sensor, so it becomes more sensitive. But the technology of this camera (again, I'm guessing here) is probably dated when compared to the latest stuff available. I get very clean image from my current crop of Sony FDR-AX100 and FDR-AX53 cameras. So, when you pump up the voltage, the sensor becomes more sensitive, but is also susceptible to noise, which it processes just like the rest of the light hitting the sensor, and you get that grain in your recording. Just spend some time testing your camera and noting what manual settings you have selected for each test clip of a scene with a non-changing level of light. Set the shutter to 1/15 and gain to 0dB and aperture as wide as it will go; f/1.4, f/2, f/2.8 etc, whatever it can do for the zoom level you're at. This is your base-line recording. Now, bring the shutter up to 1/30, then 1/48 and keep gain at 0dB. You should get a darker image by doing this. Next, repeat the process at the three shutter speeds, but increase gain to +3dB and then go to +6dB. Take a look at these test clips on a larger screen and see where the grain is too much for your tastes. I don't know any other way to acquire this information. I have to do these painstaking tests all the time if I am going to use the camera in available light conditions. I don't find the manufacture's specs all that helpful. What they consider 0dB may actually have a bit of extra voltage going to the sensor and that's why on some cameras I have to go to -3dB for what I would call a clean image. Test, test, test.

My 2 cents.

Mark
 
Hi Mark,

Brilliant! thank you for your great advice and assistance, and please "School" Away., all great stuff! I've been shooting video for many years, but mostly documentary, just now trying to be more of a conscious of the output and I'm now im business as a pro videographer.

Happy New year!

Tony
 
I was just looking at the settings, I always shoot manual Iris/focus but the shutter is very limited, 1/60 to 1/24 1/12 and the gain is at 0db, no way to adjust any lower,. Can't wait to get my new panasonic camera soon. Thanks again.
 
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