Motion Blur on HD100U at DVinfo.net

Brian Duke · November 11th, 2005, 02:55 AM

Hey,

I seem to be getting some motion blur when I pan with the HD100U. I.e. When I pan to an object the picture seems to get motion blury until I stop panning. Anything I can do to keep the image I am panning on crips and clear?

Thanks

Paul Wags · November 11th, 2005, 05:31 AM

Hi Brain
I get the same with the FX1 on some of my underwater clips when Im zoomed in very tight an have the whole picture lit up with my HID lights and move with the object.

I will load up a very good example of motion blur soon. Interesting that you have it on your camera though.

Paul

Paul Wags · November 11th, 2005, 05:32 AM

Opps sorry about that

Brain, mistyped...Brian...

Tim Dashwood · November 11th, 2005, 06:05 AM

Are you on 1/24th shutter? You should be on 1/48th for normal shooting. 1/100 if you want the "Saving Private Ryan" look.

Steve Mullen · November 11th, 2005, 06:13 AM

Quote:

Originally Posted by Brian Duke

Hey,

I seem to be getting some motion blur when I pan with the HD100U. I.e. When I pan to an object the picture seems to get motion blury until I stop panning.

Thanks

Are you shooting with the Motion Filter on or off?

That's low temporal rate shooting. You should know better than to pan -- except at exactly the correct speed. :)

With 720p I very much doubt it is MPEG-2 artifacts while with 1080i I very much suspect it is MPEG-2.

I'm finding most video shot 1080i is unwatchable as soon as there is any fast or complex motion. It gets killed in the HDCAM camcorder. It gets killed in broadcast -- especially if your local station is stealing 4Mbps for a second channel. We know PBS does this -- in fact in NYC PBS fits two sub channels and the HD is horrible.

In LV stations are selling their "unused" bits to a over-the-air cable service. With 1080i there are no unused bits!

720p60, however, can exist fine on about 16Mbps so it is acceptable -- but morally wrong -- to use these extra bits. :) Use them all -- I say!

Laszlo Horvath · November 11th, 2005, 07:21 AM

Quote:

Originally Posted by Tim Dashwood

Are you on 1/24th shutter? You should be on 1/48th for normal shooting. 1/100 if you want the "Saving Private Ryan" look.

Tim, here in Canada I use 1/30 shutter, because I find it nicer, smoother then 1/60. I'm right, or this is just to me?
Also, the "Saving Private Ryan" look is 1/100 in NTSC land too?

Please let me know
Laszlo

Tim Dashwood · November 11th, 2005, 08:03 AM

Quote:

Originally Posted by Laszlo Horvath

Tim, here in Canada I use 1/30 shutter, because I find it nicer, smoother then 1/60. I'm right, or this is just to me?
Also, the "Saving Private Ryan" look is 1/100 in NTSC land too?

Please let me know
Laszlo

Well, film running at 24fps typically has a normal 180 degree shutter and will expose 1/48th of a second per frame. Variable shutters can be closed down to decrease exposure and motion blur (90degrees in the case of "Saving Private Ryan" = 1/96th second exposure per frame.) The same math applies when you overcrank, so shooting at 48fps, would yield 1/96th of a second exposure per frame.
Normal NTSC interlaced video exposes 1/60th per full frame.
Normal PAL interlaced video exposes 1/50th per full frame.

Anything below 1/48th will give unnaturally long motion blur not possible in the film world. This is a tell-tale sign something was shot on video, even if it is 24P (that's why the taxi scenes in Collateral look so "video-like.") The silly thing is the default shutter speed in DV mode on the HD100 is 1/24th (same on the XL2.) I don't understand that logic.

Anything above 1/60th (film or video) will be in the creative zone. For example, sports are often shot at very high shutter speeds to capture details for slo-mo replay.

Brian Duke · November 11th, 2005, 09:47 AM

Quote:

Originally Posted by Steve Mullen

Are you shooting with the Motion Filter on or off?

I don't know what motion filter is, but I do have the motion smooth turned ON. Hope that isn't the problem, as my understanding all it does it to make smoother transitions from Ext to Int and vice versa.

Kenn Christenson · November 11th, 2005, 09:57 AM

Turn the motion smooth function off. It's an added "feature" meant to smooth out the judder that you sometimes see when doing pans. Keep your shutter at 1/48/sec. as has been recommended in the other posts and you should be fine. (But keep your pans slow or you'll start seeing the judder.)

Brian Duke · November 11th, 2005, 10:05 AM

Quote:

Originally Posted by Tim Dashwood

Are you on 1/24th shutter? You should be on 1/48th for normal shooting. 1/100 if you want the "Saving Private Ryan" look.

When I click status it says Shutter off [1/48]. Is that correct? How do i change it? I tried to go into LCD/VF to change it, but I couldn't find it.

Brian Duke · November 11th, 2005, 10:07 AM

Quote:

Originally Posted by Kenn Christenson

Turn the motion smooth function off. It's an added "feature" meant to smooth out the judder that you sometimes see when doing pans. Keep your shutter at 1/48/sec. as has been recommended in the other posts and you should be fine. (But keep your pans slow or you'll start seeing the judder.)

Pardon my ignorance, but I am new =). If the motion function is supposed to smooth out the judder, why would I turn it OFF? Wouldn't it make sense to keep it ON?

Also, can't find where the shutter control is. Thanks

Kenn Christenson · November 11th, 2005, 11:34 AM

The camera "smooths out" the judder by giving you the blur you noted in your original post.

The judder effect is a result of the lower motion sampling of shooting at 24fps. Motion picture camera operators deal with this problem all the time (mostly by slowing down their camera moves.)

I don't remember how to adjust the shutter (I've only operated it for a day or so.) But I'll bet the default shutter speed at 24P is 1/48. I'm sure your operating manual will tell you how to access the shutter controls.

Tim Dashwood · November 11th, 2005, 12:10 PM

Just push the shutter button in and then rotate it to adjust. However, normally it should be "off" which defaults to 1/48th.

I have tested motion smoothing and think I know how it works.
When in 24P mode, the CCDs actually sample at 48Hz. Only half of those frame captures are actually written to tape, but with motion smooth on, it appears that each of the 24 frames written to tape has a "mixed" image with the another frame before (or maybe after) it. IMHO, this isn't a feature that has much use for any filmmaker. I'm sure it was intended as a way to simulate the smoothness of "interlaced" video, but it doesn't really work.

Here's my test:
Right-click and download these m2t files to your computer.
Motion smoothing off (9.7Mb):
http://homepage.mac.com/timdashwood/...smooth_off.m2t

Motion smoothing on (11.4Mb):
http://homepage.mac.com/timdashwood/..._smooth_on.m2t

Keep in mind that "judder" as you call it has been around for over 100 years in film and filmmakers have learned how to work within the limits of it. If you have an American Cinematographer's Manual you can look up the chart on recommended pan speeds. For a taste, they recommend that if are going to pan 90 degrees on your widest focal length (the book has 35mm focal lengths) then it should take 9 seconds.

Brian Duke · November 11th, 2005, 03:25 PM

Quote:

Originally Posted by Tim Dashwood

Just push the shutter button in and then rotate it to adjust. However, normally it should be "off" which defaults to 1/48th.

Thanks Tim. When I try to move the shutter the screen simply says Shutter off [1/48] and won't allow me to adjust it. I think you adjust it in your frame settings from reading the manual. Or maybe mine has a defect.

Will check out your tests and do some of my own to see if my judder improves. =)

Nate Weaver · November 11th, 2005, 03:33 PM

You push it in first to "Turn on the shutter", and THEN rotate to change the value.

November 11th, 2005, 02:55 AM	#1
Brian Duke Major Player Join Date: Oct 2005 Location: Hollywood, California Posts: 899	Motion Blur on HD100U Hey, I seem to be getting some motion blur when I pan with the HD100U. I.e. When I pan to an object the picture seems to get motion blury until I stop panning. Anything I can do to keep the image I am panning on crips and clear? Thanks

November 11th, 2005, 03:33 PM	#15
Nate Weaver Wrangler Join Date: Oct 2002 Location: Los Angeles, CA Posts: 2,100	You push it in first to "Turn on the shutter", and THEN rotate to change the value. __________________ My Work: nateweaver.net

November 11th, 2005, 05:31 AM	#2
Paul Wags Ruler of the DownUnder UnderWorld Join Date: Jul 2005 Location: Cairns- Queensland - Australia Posts: 248	Hi Brain I get the same with the FX1 on some of my underwater clips when Im zoomed in very tight an have the whole picture lit up with my HID lights and move with the object. I will load up a very good example of motion blur soon. Interesting that you have it on your camera though. Paul

November 11th, 2005, 05:32 AM	#3
Paul Wags Ruler of the DownUnder UnderWorld Join Date: Jul 2005 Location: Cairns- Queensland - Australia Posts: 248	Opps sorry about that Brain, mistyped...Brian...

November 11th, 2005, 06:05 AM	#4
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	Are you on 1/24th shutter? You should be on 1/48th for normal shooting. 1/100 if you want the "Saving Private Ryan" look.

November 11th, 2005, 09:57 AM	#9
Kenn Christenson Regular Crew Join Date: Oct 2003 Location: Medford Oregon Posts: 152	Turn the motion smooth function off. It's an added "feature" meant to smooth out the judder that you sometimes see when doing pans. Keep your shutter at 1/48/sec. as has been recommended in the other posts and you should be fine. (But keep your pans slow or you'll start seeing the judder.)

November 11th, 2005, 11:34 AM	#12
Kenn Christenson Regular Crew Join Date: Oct 2003 Location: Medford Oregon Posts: 152	The camera "smooths out" the judder by giving you the blur you noted in your original post. The judder effect is a result of the lower motion sampling of shooting at 24fps. Motion picture camera operators deal with this problem all the time (mostly by slowing down their camera moves.) I don't remember how to adjust the shutter (I've only operated it for a day or so.) But I'll bet the default shutter speed at 24P is 1/48. I'm sure your operating manual will tell you how to access the shutter controls.

November 11th, 2005, 12:10 PM	#13
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	Just push the shutter button in and then rotate it to adjust. However, normally it should be "off" which defaults to 1/48th. I have tested motion smoothing and think I know how it works. When in 24P mode, the CCDs actually sample at 48Hz. Only half of those frame captures are actually written to tape, but with motion smooth on, it appears that each of the 24 frames written to tape has a "mixed" image with the another frame before (or maybe after) it. IMHO, this isn't a feature that has much use for any filmmaker. I'm sure it was intended as a way to simulate the smoothness of "interlaced" video, but it doesn't really work. Here's my test: Right-click and download these m2t files to your computer. Motion smoothing off (9.7Mb): http://homepage.mac.com/timdashwood/...smooth_off.m2t Motion smoothing on (11.4Mb): http://homepage.mac.com/timdashwood/..._smooth_on.m2t Keep in mind that "judder" as you call it has been around for over 100 years in film and filmmakers have learned how to work within the limits of it. If you have an American Cinematographer's Manual you can look up the chart on recommended pan speeds. For a taste, they recommend that if are going to pan 90 degrees on your widest focal length (the book has 35mm focal lengths) then it should take 9 seconds.