30P Issues

[Les Jarrett]

I've been trying to master shooting in progressive, and have been shooting traffic on city streets, since most of what I do involves transportation.

Today I shot 30p in nice sunlight, and again had the same results. Just past the center of the screen, the image began to blur, and was very blurred at the corners. If the shutter was off, it was just blurry. But even at 1 40th, ECS of 60, 70, or 80 there were issues. At 70 and 80 I could clearly see two images of wheel rims on the monitor.

To rule out my HD monitor, i hooked up the video out to a plain old NTSC TV, and got the same results.

When I shoot a control in 1080i, the picture only begins to blur at the very edges of the picture, not near the middle as with P.

The problem has to be something I am doing, I see the whole rest of the video worlds results, including some beautiful work from members of this forum.

When shooting in P I turn the shutter either on or off, and if on, I turn it on, and then set the shutter to the desired setting.

Is there anything else I need to be doing? Any menu settings that I am missing? I'm beginning to wonder if there are problems with the camera, but is shoots great in 1080i, and I would think if something was wrong BOTH P and I have issues.

Any ideas?

[Alister Chapman]

Which camera are you using? As 30P over HDSDi is not a format accepted by most monitors the camera outputs 30P as within an interlace signal called PsF, it may be that your monitors are not decoding this correctly. Also be very careful if using a computer monitor as you can get all kinds of frame rate mis-matches with computer monitors.

Shooting 30P you would normally use a 180 degree or 1/60th shutter. Shoot at anything less than 1/60th and you will have more blur than shooting 60i as the shutter is open for longer.

[Doug Jensen]

Les, why don't you shoot some test footage and post it at Vimeo so we can look at it.

I would also suggest doing an ALL RESET beforehand, and then setting your shutter speed and other settings accordingly.

[Les Jarrett]

Gentlemen,

Thanks for your responses. Alister, I'm using the 350, and your monitor suggestion makes perfect sense. I only went as far as doing the HDSI right out of the camera to the monitor, then when I was quite agitated at constant bad results, I hooked up the video out into a plain old TV, and got the same bad images.

I have not imported one frame into the computer, much less going the whole way and making a BDR.

I suspect that I'm shooting wonderful video and don't know it.

Doug, I'll try to post some footage, will be a couple of days or so before I can get to it.

Thanks so much.

Les

[Les Jarrett]

Doug,

Here's a link to what I was shooting the other day. It's raining today, so not the best time to be standing outside shooting traffic, so nothing was reset.

This was shot with my 350 in 30P at the ECS settings described in the audio. Put in an FCP timeline in XDCAM HD HQ in 30p mode. It was then exported to a Quicktime file with the same settings (progressive, framerate etc.). Then uploaded. You can see my blurring issues.

In 1080i the cars only blur at the very corners of the screen. Any thoughts appreciated.

XDCAM HD 30P Test on Vimeo

[Doug Jensen]

Les,

Your video looks perfectly normal to me.
This is what I was trying to explain in my post #22 a week ago on this other thread:
http://www.dvinfo.net/forum/sony-xdc...60i-30p-2.html

When the cars are far away and small in the frame, they aren't moving very quickly across the frame, so the there isn't much blur. But as the cars get closer to the camera their relative motion across the screen is many times faster. The faster the relative motion through the frame -- the more motion blur there will be. It's just physics. If there wasn't motion blur as the cars moved that quicly across the frame you'd see a stobe effect and wouldn't look natural at all.

When you get better weather go try the same setup at 1/1000th. The cars will be a lot sharper as they exit the screen, but look how jumpy the video looks when played back at normal speed.

In this situation motion blur is a good thing. Find a shutter speed betwen 1/60 and 1/125th looks good to you and stick with it.

[Doug Jensen]

(deleted)
Oops. I accidentally posted twice. Sorry.

[Daniel Larson]

Les,

Were you shooting with the lens wide open? I found that my lens when wide open is not as sharp as a stop or two closed.

Dan

[Les Jarrett]

Dan,

It was evening, and I had a few minutes and just threw the camera on the tripod, didn't spend much time tweaking, so yes, it was pretty much wide open.

Thanks for the input.

Les