AC160 Grainy image in lower light from AC160

I

Iceberger

New member
Hi guys, I need your help. I find the picture from my camera quite grainy in lower light conditions even at 0dB setting and I am concerned that the camera is malfunctioning. Below is the link to "test clips" from my cam & I was wondering if you guys could take a look and tell me if your 160 produces a similar grain in lower light, or if there is something wrong with my cam? I don't have any place on anyone where I could compare it with and I will welcome any feedback, so that I can either rule out or confirm my concern of camera malfunctioning.

Settings are:
gain: 0dB
master pedestal: -3
DRS: off
all other settings at default
scene 6 (but the grain is present even when using other scenes 1-5)

Recording mode:
1080 30p
shutter and iris - manual

Grainy areas:
clip1 - against green side of the building
clip2 - against rocks and pebbles
clip2 - everywhere

http://icebergfilms.com/wp-content/uploads/videogallery/testing3.mov

THANK YOU NOTE:
I already posted this question to Facebook Panny group where I did get a lot of helpful tips from it's members (THANK YOU LOUIS), but unfortunately, the problem still persists, so I decided to post it here as well and ask you guys for your opinion.
 
From what i'm seeing, those scenes should not be a problem for the AC160, i have the AC130 and i don't even think that that the scenes fall under low light, check your settings. I would set the camera on default and see what comes out.
 
The problem in the 3rd and last clip that makes it look so horrible is simple mirage distortion ( also sometimes referred to as heat haze ). That is why it looks so awful.

You would have seen this yourself with your own naked eye, if you had been looking through a pair of binoculars or a telescope at the same magnification level that you had your AC160 zoomed into.

Mirage is best know in the desert, where it can become so intense that one can even see it with the naked eye. But the fact is that the mirage effect doesn't need a burning hot dessert to exist. And often on a warm day, where the naked eye sees no mirage at all, you can easily see it by looking through any magnified optics.

If you had simply zoomed the lens out wide, all of the mirage distortion would have all disappeared.

If shooting under similar conditions in the future, I would keep your zoom magnification down real low, no more than something in the 6 to 10x power range at the very max, depending on the conditions.

Here is some basic info on how mirage works:

http://en.wikipedia.org/wiki/Mirage

.
 
Thank you guys for your feedback, I really appreciate it.

Lance, thank you so much for your advise, I am very glad that that ugly distortion of 3rd clip wasn't caused by the camera malfunctioning.

Just wondering, what is your opinion regarding the grain in clips 1 and 2? I should also mention that both clips (1 & 2)were shot in the evening, in twilight, just after the sun disappeared, but there was still some light left, it wasn't a darkness yet.
 
These shots look on par with what I would expect from the camera. A little noisy in the lows maybe, but CINE D isn't the cleanest as it's trying to maximize dynamic range. Try dropping your master pedestal a few more clicks and/or do a manual black balance. Check out the picture styles Panasonic released soon after the camera. Some good ones in there like CLEAN and HOLLYWOOD

http://www.panasonic.com/business/provideo/scene-files-new.asp?model=AC160
 
Thank you Nate for helping me with this.
I actually did try CLEAN style, but the grain was still there, so I returned to default styles. The fact that CLEAN style still showed grain raised my concern that something might be wrong with the camera, because everyone says how noiseless the image is.
But when you say that you expect this kind of noise, that would mean that my camera is not malfunctioning.
 
What does it look like with good light? There isn't one best profile that works for everything. Depends on your scene.

Again, have you black balanced?
 
Hi Iceberger, can you recall what your focal length was and at what shutter speed and aperture? and you say you were fully manual-what method were you using to evaluate "correct" exposure? All the comments above are valid but without absolute references on how light/dark it was, it is difficult to judge. As Lance says, forget scene 3 he is spot on- scene 2 looks untidy, but rest assured there is nothing wrong with your camera, it is something that can be tweaked with settings- again I agree with Nate on this one.. Do you have a copy of Barry Green's book? much golden info in that and well worth seeking a copy.Cheers!Rod
 
Hello Rod,
THANK YOU, I can't tell how much I appreciate your input.
I can't recall the settings, so I did shoot two new clips today and wrote down all settings, so here it is:

http://icebergfilms.com/wp-content/uploads/videogallery/testing4.mov

LIGHTING CONDITIONS: twilight, right after sun disappeared behind horizon. Still some light left.
SETTINGS:
1080 30p
shutter: 1/60
aperture: F3.8
ZOOM: MF 20.0m, Z 10.3mm
Tool used to determine exposure: waveform
gain: 0dB
detail level: +2
V detail: +2
Detail coring: +2
NOTE: I have tried Detail level, V detail and Detail coring set at 0 before, and the grain was the same, so it doesn't seem to have any effect
master pedestal: -3
a.iris: 0
DRS: Off
Gamma: HD Norm
Knee: auto
Matrix: Norm1
skin tone dtl: Off

Please, let me know your thoughts.
No I don't have Barry's book, but will try to get one.

Best,
Paul
 
Hi Iceberger,thanks for that. Now , your detail levels will accentuate grain. In case you don't know this, it is important to understand some facts about the scales: detail and vdetail range from -7 to plus 7. so you would think 0 is er-- no detail sharpening- wrong. Barrys book explains this clearly- surprisingly -7 is no electronic enhancement, so 0 = 50%, so +2 is even more. I shoot at -4 on both these , which gives a modest amount of sharpening. I don't believe this is in the camera manual (I use the term manual loosely!) But Barry's book explains this with succinct clarity and I certainly didn't know this until I read the book. It also explains the interaction between the various settings and they interact with each other- it is not a linear relationship for every combination. So try turning the detail and vdetail down to -4 and see how it goes. Cheers! Rod
 
Hello Rod,
THANK YOU so much for this. This is soooo valuable info, because it never came to my mind that these settings work that way. Yes, I definitely need that book. I can't wait to test it this evening.
THANK YOU AGAIN, I will send you a note after the testing.
Cheers,
Paul
 
Glad to help- that's what happens here! (and I have only shared some of Barry Green's wisdom!)Cheers!Rod
 
You may actually have a camera issue that should be checked under warranty. It could be an amplifier issue-visually.

Why? The fact you tried the scene file called CLEAN leads me to believe there is an issue with the camera. CLEAN has very low detail values. You can check the scene file via the menu setting and observe a very low detail setting and other lower detail values.
 
Thank you Lou for your input.
That wouldn't be a good news. I didn't check the detail values of CLEAN scene file, but I will try to install it again and do some testing again. I still need to do the testing with the settings suggested by Rod. (I wanted to do it last night but didn't have time). I am also trying to find someone in Vancouver who has that camera, so that I could compare it. But of course, the next step is to send it to Panasonic Canada, which sucks because that means shipping it to Ontario and being stuck without a camera for weeks, so it is a last resort.

Thank you Lou again for your input.
I really appreciate all inputs from all of you guys.

Best,
Paul
 
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