25P Observations at DVinfo.net

Bob Grant · January 8th, 2007, 04:14 PM

I did some very crude and quick tests on our V1P yesterday. These tests did not entail recording to tape so they're far from exhaustive but they might contain one interesting piece of information.

We were only looking for signs of the 'marching ants' problem at the time. What we found was nothing beyond expected aliasing issues. We used a white card on a black background with the card at roughly 45deg. With the component outputs connected to a Dell 2407 monitor the staircasing on the diagonal edges was quite noticable up close to the monitor. The steps appeared to be 1 pixel in size. As far as we could tell exactly what has to happen happened. This affects every camera and/or monitor.

For a comparison we replaced the V1P with a Z1. The resulting image showed exactly the same staircasing.

There was no difference in the staircasing from the V1P in progressive and interlaced.

What I did notice was an as expected increase in noise from the V1P in progressive over interlaced. As I wasn't looking for anything other than the marching ants problem I cannot comment on much else. I certainly didn't notice anything else odd about the p image, detail in the black background held very well.

However I did notice one thing. In p when the noise comes up the noise level was way worse on some details of the black background. It looks very similar to the results from using dynamic noise reduction. If that's what the camera is using then it's quite possible that certain subjects and light levels could indeed be the cause of problems that some are still seeing post the firmware update.

I'd suggest that anyone trying to see the problem needs to compensate their comparison between p and i by dropping the light levels in i by 2 stops and adding 6dB gain to bring the noise level up. I suspect this issue will be more noticeable in p than i but it's not an issue unique to shooting in p.
Shooting in bright sunlight I doubt anyone will see the problem also. You need lower light levels with fine detail.

Boyd Ostroff · January 8th, 2007, 05:38 PM

Everyone: The other thread on this topic was intentionally closed, and Chris has specifically asked that the discussion be put on hold for the time being. He's out of town and checking in from time to time; I'm sure you will hear from him in person soon. In the meantime please refrain from starting additional threads about V1P problems. We understand your concerns, but future threads on this topic will be immediately removed until Chris can review everything.

January 8th, 2007, 04:14 PM	#1
Bob Grant Trustee Join Date: Nov 2005 Location: Sydney Australia Posts: 1,570	25P Observations I did some very crude and quick tests on our V1P yesterday. These tests did not entail recording to tape so they're far from exhaustive but they might contain one interesting piece of information. We were only looking for signs of the 'marching ants' problem at the time. What we found was nothing beyond expected aliasing issues. We used a white card on a black background with the card at roughly 45deg. With the component outputs connected to a Dell 2407 monitor the staircasing on the diagonal edges was quite noticable up close to the monitor. The steps appeared to be 1 pixel in size. As far as we could tell exactly what has to happen happened. This affects every camera and/or monitor. For a comparison we replaced the V1P with a Z1. The resulting image showed exactly the same staircasing. There was no difference in the staircasing from the V1P in progressive and interlaced. What I did notice was an as expected increase in noise from the V1P in progressive over interlaced. As I wasn't looking for anything other than the marching ants problem I cannot comment on much else. I certainly didn't notice anything else odd about the p image, detail in the black background held very well. However I did notice one thing. In p when the noise comes up the noise level was way worse on some details of the black background. It looks very similar to the results from using dynamic noise reduction. If that's what the camera is using then it's quite possible that certain subjects and light levels could indeed be the cause of problems that some are still seeing post the firmware update. I'd suggest that anyone trying to see the problem needs to compensate their comparison between p and i by dropping the light levels in i by 2 stops and adding 6dB gain to bring the noise level up. I suspect this issue will be more noticeable in p than i but it's not an issue unique to shooting in p. Shooting in bright sunlight I doubt anyone will see the problem also. You need lower light levels with fine detail.

January 8th, 2007, 05:38 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,788	Everyone: The other thread on this topic was intentionally closed, and Chris has specifically asked that the discussion be put on hold for the time being. He's out of town and checking in from time to time; I'm sure you will hear from him in person soon. In the meantime please refrain from starting additional threads about V1P problems. We understand your concerns, but future threads on this topic will be immediately removed until Chris can review everything.