Ralph Oshiro
Veteran
THis post has been deleted.
Last edited:
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
And about the PDW-F330? I'm thinking to buy one but I've doubts regarding a comparision in terms of film-like color properties.NBCshooter said:When lit well, the HVX had extremely beautiful colorimetry, and a very naturalistic characteristic curve. In side-by-side comparisons, the HVX' overall image quality (aside from resolution) seemed very comparable to the BVW600's colorimetry.
NBCshooter said:Illuminated at 20 footcandles (need to confirm this with another light meter--may have been miscalibrated), with all cameras irised ar their arbitrary "starting point" apertures above, the HVX appeared significantly noisier than the 2/3" cameras. I opened each camera's iris by one full stop. Still, the HVX was noticably noiser than the other cameras. I opened up one more full stop. The noise in the HVX picture virtually disappeared.
NBCshooter said:When I turned the iris ring on the HVX one more time to f/2.8, the exposure was then more "normal," and the noise became virtually non-existant, or at least very comparable to the 2/3" cameras.
Jim:Jim Arthurs said:Thanks, that completely clears what you did! Underexposing the HVX is a bad thing. But, this brings up another question for me, and that is "why?".
Look at it this way; let's say you're at your first test settings, where you were at f8 with the HVX and everything was very dark. Without adjusting the camera, what would happen to that exact same setup if you pounded enough extra light into the scene to bring it up to a proper exposure for that fstop? Would the noise go away, I wonder? Seems like it would, based on your tests and what others have said.
This is puzzling to me and my film background. If I underexpose film, and make no attempt to bring up the levels at the transfer or in printing, the grain stays the same as it would when properly exposed. You just have a dark image. Of course if you "print up" or attempt to normalize you'll introduce grain, but that's not what I'm talking about.
Am I crazy here? Am I missing something basic about ccd imagery? Does every shot have to have an area of "normal" exposure to drive the noise demons away? What happens to the areas of the image that are 2-3 stops below middle grey? Are they always filled with noise, or just when the overall image has no proper points of exposure? Help!!!
Jim Arthurs
I'll give you an example. I'll take my DVX100 or VX2000 and shoot blue sky in the daytime. I'm at f/11 with ND on, so light level is NOT the issue. But the contrast in the scene is very low. Guess what? LOTS of noise!NBCshooter said:It seems that when given a low contrast scene, the signal processing electronics in any CCD or CMOS based imaging system tends to generate more noise.
My wild-azz, totally uninformed guess would be that the signal processing electronics account for this behavior. The actual response characteristics of the CCD imager may also play a role, but I know nothing about CCD design with respect to this subject. Video cameras don't have "ISO" settings, they have "gain" settings. The response curve behavior is beyond the control of the external gain setting on the camera, and is something internal to the camera's processing electronics, and possibly the imager.mochouinard said:I might sound stupid, but is there a ISO setting on the camera ?
I know on my Canon 20D noise come from high ISO when in low light. So could it be the CCD ISO is changed by the processor to different levels ?
It the only thing that come to mind. High ISO increase the NOISE.
It pretty much the only way I get visible noise, because if my scene is dark, well it only dark at low iso, no noise.
But yes the Processor could be the one increasing the brightness... But I would think it might be more the chip telling the CCD to change it ISO level.
Out of context : It could be nice to have a 'RAW' mode like in digital camera, where it record without color correction but save in the metatag this info, then when opening in a editor, the editor apply the filterMaybe in the next version
NBCshooter said:Jim:
Believe me, I appreciate your confusion. This has been turning out ot be a very interesting exercise. I've been asking myself the EXACT same questions. And no, your conclusion is NOT true (thank god). It seems that when given a low contrast scene, the signal processing electronics in any CCD or CMOS based imaging system tends to generate more noise. I'm not an engineer, I don't know the reasons for this.
For my SciFest short, I shot a VERY high contrast, low key scene with my very noisey DVX100 (non-A). In that scene, more than 95% of the frame was in shadow or in near-black IRE values. But the subjects were heavily backlit and the scene had a lot of contrast. Guess what? NO NOISE! The CCD and the DVX's signal processing electronics saw a "decent" IRE spike SOMEWHERE in the CCD and figured, "Hmmm, this DP has quite a lot of light on one SMALL piece of my CCD, therefore, I won't act so noisy on his near-black parts of the CCD."
Well, that's comforting to know that an informed guy like Barry had also come to similar conclusions. Could you post a link to the thread where he mentions this? Since you also have confirmed this observation, now at least I know, I'm not "imagining" this phenomenon! Thanks for the info!x2mag68 said:Yea thats totally true. Barry mentioned this a few days ago, and i never even noticed it until he says so. Then i went out, shot some stuff in the dark with a few areas Properly lit ( like above 50 or 60 ire, noone says you need 99IRE t ge the chips to run "quiet") and suddenly the image just Pops! its really interesting.
ITs like finding a new tool to use for making low light stuff look good.