How to get rid of Motion blur on fast moving object? at DVinfo.net

Gonzague Alexandre · March 16th, 2007, 08:22 AM

Hi folks

I really get mad and turn in circle. I want to shoot a fast moving object (car) with my HVX on a Tripod. Each time I shoot I have motion blut and EVEN worse, lately I had motion blur during a PAN (slow pan) of the car Stop. I am sure that I am doing something wrong and I cannot put the finger on what is wrong... This turn me mad !

Basically I set my HVX to 720p30 (n mode) and shoot with a Shutter speed of 500 up to 1000 when I have a VERY VERY bright sky. The out put video will be in 720p30 (WMV or DivX).

Now Is the 720p30N is suitable for what am I doing ? If I use 720p60 and mix with 720p30N will I get the same result once the encoded in DivX or WMV HD ?

Now you may ask WHY on earth I stick to 720p30N... Simply to get 16min on my 8GB P2 card, but since I have a laptop with P2 Genie always with me I can change this setting.

I would much appreciate your wise answers on this matter, since we do not ALWAYS have a 2nd car for shooting I would like to know how can I have nice shoot of a moving car (or good pan) without motion blur....

Cheers

Jason Boyce · March 16th, 2007, 11:16 AM

I would probably shoot 60fps if I were you, or even shoot slow motion and then speed it up in post (if sound sync isn't an issue). If your shutter speed is maxed then the only way you can cut out more blur is to shorten the time recording the frame, which would be to shoot a higher framerate. Maybe try framerates between 30 and 60 first to see if that helps before you go all the way to 60.

Dean Sensui · March 16th, 2007, 02:04 PM

From the description I think Gonzague is seeing the jitter from shooting progressive frames, rather than interlaced video.

"lately I had motion blur during a PAN (slow pan) of the car Stop."

So if his shutter speed is 1/500 and he's slowly panning a car that's not even moving then the problem is jittering or stuttering.

Perhaps do a test with slower shutter speeds with progressive frames to make the movement appear smoother. Can't hurt. Especially since we already know that fast shutter speeds didn't solve the problem.

Either that, or shoot interlaced video.

Jon Fairhurst · March 16th, 2007, 02:40 PM

Are you using an LCD monitor? Older LCDs have strong motion blur. Newer, say 4ms, panels are much better. The 120 Hz panels are really quite good.

A slow shutter will leave trails and smear the video. LCD motion blur tends to be seen as simple loss of detail during motion.

Daniel Browning · March 16th, 2007, 02:43 PM

I agree with Dean. The OP is seeing normal progressive stutter/jitter. The only other possibility is his playback method is flawed (i.e. compressed, high-latency display, etc.).

Gonzague Alexandre · March 17th, 2007, 03:56 AM

Thanks Guys...

Dean >
Thanks I may had left the cam on 1/500 for the PAN... I will try this ASAP.

But this do not fix the "motion" blur that appear if the camera is Fix and the car is moving. For example I have the car in a Curve (you get profile, face, profile) so in this setup we have motion blur (profile) no motion blur (face) motion blur again (profile)...

Anyway I will try play with frame rates and so on, but if you have any other good advises, SHOOT !

Cheers

Gonzague Alexandre · March 22nd, 2007, 06:44 AM

OK I made some more test, and MAN I must be stupid.... coz I cannot get ride of this "BLUR"

Please have a look at yourself and tell me what do you think...

http://gagay.free.fr/video/blur.wmv

this is really get me MAD... the difference between a fix or moving picture is so huge.... WHat are you settings ?

Mike Teutsch · March 22nd, 2007, 06:59 AM

Doesn't look like motion blur to me, it looks like a software problem. How does the footage look when played back on the camera itself? Motion blur is not that jerky, it's blurred.

JMO---Mike

Gonzague Alexandre · March 22nd, 2007, 07:37 AM

Quote:

Originally Posted by Mike Teutsch

Doesn't look like motion blur to me, it looks like a software problem. How does the footage look when played back on the camera itself? Motion blur is not that jerky, it's blurred.

JMO---Mike

Looks OK on the camera, but then again the LCD is so small how can you be certain of that ?... I am editing my video with Edius 4.01... Or is it the WMV ?

R Geoff Baker · March 23rd, 2007, 06:13 AM

Firstly, I don't see blur at all -- blur is a softening and smearing of the image -- I see stuttering or more descriptively 'strobing'. And strobing is exactly what I'd expect if you shoot with a shutter speed higher than the frame rate allows ...

If your subject is static, it doesn't matter how fast your shutter speed as there is no movement between frames ... but if you shoot with a shutter speed 1/500 of a second, and you shoot frames 1/30 of a second apart, and there is movement, your result has a temporal discontinuity between each frame. It is precisely the ABSENCE of blur that makes this look bad. Instead of smearing its way through the frame, and revealing the movement in a way that is both logical and 'natural', the subject jumps -- it has moved a little between each frame, but there is no visual indicator of how or why ... it stutters and strobes and generates an odd looking image. You create a series of very sharp stills, with gaps between them. The faster the pan or movement, the more apparent the gaps are.

If your shutter speed is exactly related to your frame rate, the next frame is recorded the instant the last one ended, and so there are no gaps in image. Objects may move while the shutter is open, creating blur, but no jumping.

In cinema, this strobe effect was used effectively in Saving Private Ryan on the D-day landing scenes, to create an eery and other-worldly look. On the swing scene of In The Garden of Good and Evil it was used accidently and stupidly by a DOP that didn't match the cameras shutter speed to the frame rate, and the scene was 'ruined' in a technical sense. In general, a DOP chooses a shutter speed that is 'invisible', so if there is movement, panning or tilting you stick to the frame rate -- you'll note that if you truck in during a shot you can get away with a higher shutter speed as the motion is not so disturbing in that axis.

I don't think you will get the result you expect using the technique you are trying. Increase your frame rate, but don't change your shutter speed if you want smooth motion -- stick with a shutter speed of 1/frame rate for the most natural looking result.

GB

Gonzague Alexandre · March 24th, 2007, 09:02 PM

Quote:

Originally Posted by R Geoff Baker

Firstly, I don't see blur at all -- blur is a softening and smearing of the image -- I see stuttering or more descriptively 'strobing'. And strobing is exactly what I'd expect if you shoot with a shutter speed higher than the frame rate allows ...

If your subject is static, it doesn't matter how fast your shutter speed as there is no movement between frames ... but if you shoot with a shutter speed 1/500 of a second, and you shoot frames 1/30 of a second apart, and there is movement, your result has a temporal discontinuity between each frame. It is precisely the ABSENCE of blur that makes this look bad. Instead of smearing its way through the frame, and revealing the movement in a way that is both logical and 'natural', the subject jumps -- it has moved a little between each frame, but there is no visual indicator of how or why ... it stutters and strobes and generates an odd looking image. You create a series of very sharp stills, with gaps between them. The faster the pan or movement, the more apparent the gaps are.

If your shutter speed is exactly related to your frame rate, the next frame is recorded the instant the last one ended, and so there are no gaps in image. Objects may move while the shutter is open, creating blur, but no jumping.

In cinema, this strobe effect was used effectively in Saving Private Ryan on the D-day landing scenes, to create an eery and other-worldly look. On the swing scene of In The Garden of Good and Evil it was used accidently and stupidly by a DOP that didn't match the cameras shutter speed to the frame rate, and the scene was 'ruined' in a technical sense. In general, a DOP chooses a shutter speed that is 'invisible', so if there is movement, panning or tilting you stick to the frame rate -- you'll note that if you truck in during a shot you can get away with a higher shutter speed as the motion is not so disturbing in that axis.

I don't think you will get the result you expect using the technique you are trying. Increase your frame rate, but don't change your shutter speed if you want smooth motion -- stick with a shutter speed of 1/frame rate for the most natural looking result.

GB

I think I start (or start to THINK) to understand... So one more question if I want to shoot in Shutter Speed 1/500 or more, what should by my setting then 60p ?

in Operation Type I have VIDEO CAM
Frame Rate DEFAULT
SYNCHRO SCAN 1/48.0

Should I change something there too?

Ash Greyson · March 25th, 2007, 12:36 AM

There is no motion blur in the wmv file. You should change your shutter to 1/60 if you are in 30PN that will smooth it out. Also, make sure you turn OIS off...

ash =o)

Gonzague Alexandre · March 25th, 2007, 12:42 AM

Thank you Ash, but sometimes it is required in my movies (what a pompous name for what I do) to have sharp picture on fast moving cars...

Yesterday I was testing the latest Nismo Z350 and drifting in Mountains, so how can I make sure to get the best picture out of this situation

Cheers

R Geoff Baker · March 25th, 2007, 05:52 AM

As a rule, the shutter speed that will best match movement across the frame is the 1/frame rate. Having said that, you can expect that 1/2xframe rate will look almost natural, and 1/4xframe rate still reasonable. 'Frame rate', for the purpose of interlaced shooting, is field rate, so an NTSC shooter would describe 1/60 as normal if shooting interlaced.

The speed of the motion, and the type of motion (lateral, towards, away, et cetera) will vary the definition of acceptable ...

HTH

GB

Gonzague Alexandre · March 25th, 2007, 08:22 AM

Ok but....

on a HVX we have different shutter speed like 500, 1000 or 2000... but when you are in 30 or 60... I cannot use those higher setting ?!?!? I am confuse

Lets see if I have a 500 shutter speed in order to respect a full digit rule (no number like 1.33) I must have a 25fps, 1000 a 50... How can I do that.... I am really lost here

March 16th, 2007, 08:22 AM	#1
Gonzague Alexandre Regular Crew Join Date: May 2006 Location: Tokyo - JAPAN Posts: 43	How to get rid of Motion blur on fast moving object? Hi folks I really get mad and turn in circle. I want to shoot a fast moving object (car) with my HVX on a Tripod. Each time I shoot I have motion blut and EVEN worse, lately I had motion blur during a PAN (slow pan) of the car Stop. I am sure that I am doing something wrong and I cannot put the finger on what is wrong... This turn me mad ! Basically I set my HVX to 720p30 (n mode) and shoot with a Shutter speed of 500 up to 1000 when I have a VERY VERY bright sky. The out put video will be in 720p30 (WMV or DivX). Now Is the 720p30N is suitable for what am I doing ? If I use 720p60 and mix with 720p30N will I get the same result once the encoded in DivX or WMV HD ? Now you may ask WHY on earth I stick to 720p30N... Simply to get 16min on my 8GB P2 card, but since I have a laptop with P2 Genie always with me I can change this setting. I would much appreciate your wise answers on this matter, since we do not ALWAYS have a 2nd car for shooting I would like to know how can I have nice shoot of a moving car (or good pan) without motion blur.... Cheers

March 16th, 2007, 02:04 PM	#3
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	From the description I think Gonzague is seeing the jitter from shooting progressive frames, rather than interlaced video. "lately I had motion blur during a PAN (slow pan) of the car Stop." So if his shutter speed is 1/500 and he's slowly panning a car that's not even moving then the problem is jittering or stuttering. Perhaps do a test with slower shutter speeds with progressive frames to make the movement appear smoother. Can't hurt. Especially since we already know that fast shutter speeds didn't solve the problem. Either that, or shoot interlaced video. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

March 16th, 2007, 02:40 PM	#4
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Are you using an LCD monitor? Older LCDs have strong motion blur. Newer, say 4ms, panels are much better. The 120 Hz panels are really quite good. A slow shutter will leave trails and smear the video. LCD motion blur tends to be seen as simple loss of detail during motion. __________________ Jon Fairhurst

March 22nd, 2007, 06:59 AM	#8
Mike Teutsch Inner Circle Join Date: Oct 2004 Location: Port St. Lucie, Florida Posts: 2,614	Doesn't look like motion blur to me, it looks like a software problem. How does the footage look when played back on the camera itself? Motion blur is not that jerky, it's blurred. JMO---Mike __________________ Chapter one, line one. The BH.

March 23rd, 2007, 06:13 AM	#10
R Geoff Baker Major Player Join Date: Jan 2005 Location: Ottawa, ON Posts: 471	A failure to communicate Firstly, I don't see blur at all -- blur is a softening and smearing of the image -- I see stuttering or more descriptively 'strobing'. And strobing is exactly what I'd expect if you shoot with a shutter speed higher than the frame rate allows ... If your subject is static, it doesn't matter how fast your shutter speed as there is no movement between frames ... but if you shoot with a shutter speed 1/500 of a second, and you shoot frames 1/30 of a second apart, and there is movement, your result has a temporal discontinuity between each frame. It is precisely the ABSENCE of blur that makes this look bad. Instead of smearing its way through the frame, and revealing the movement in a way that is both logical and 'natural', the subject jumps -- it has moved a little between each frame, but there is no visual indicator of how or why ... it stutters and strobes and generates an odd looking image. You create a series of very sharp stills, with gaps between them. The faster the pan or movement, the more apparent the gaps are. If your shutter speed is exactly related to your frame rate, the next frame is recorded the instant the last one ended, and so there are no gaps in image. Objects may move while the shutter is open, creating blur, but no jumping. In cinema, this strobe effect was used effectively in Saving Private Ryan on the D-day landing scenes, to create an eery and other-worldly look. On the swing scene of In The Garden of Good and Evil it was used accidently and stupidly by a DOP that didn't match the cameras shutter speed to the frame rate, and the scene was 'ruined' in a technical sense. In general, a DOP chooses a shutter speed that is 'invisible', so if there is movement, panning or tilting you stick to the frame rate -- you'll note that if you truck in during a shot you can get away with a higher shutter speed as the motion is not so disturbing in that axis. I don't think you will get the result you expect using the technique you are trying. Increase your frame rate, but don't change your shutter speed if you want smooth motion -- stick with a shutter speed of 1/frame rate for the most natural looking result. GB

March 16th, 2007, 11:16 AM	#2
Jason Boyce Regular Crew Join Date: Apr 2006 Location: San Francisco, CA Posts: 77	I would probably shoot 60fps if I were you, or even shoot slow motion and then speed it up in post (if sound sync isn't an issue). If your shutter speed is maxed then the only way you can cut out more blur is to shorten the time recording the frame, which would be to shoot a higher framerate. Maybe try framerates between 30 and 60 first to see if that helps before you go all the way to 60.

March 16th, 2007, 02:43 PM	#5
Daniel Browning Major Player Join Date: Jan 2007 Location: Portland, OR Posts: 949	I agree with Dean. The OP is seeing normal progressive stutter/jitter. The only other possibility is his playback method is flawed (i.e. compressed, high-latency display, etc.).

March 17th, 2007, 03:56 AM	#6
Gonzague Alexandre Regular Crew Join Date: May 2006 Location: Tokyo - JAPAN Posts: 43	Thanks Guys... Dean > Thanks I may had left the cam on 1/500 for the PAN... I will try this ASAP. But this do not fix the "motion" blur that appear if the camera is Fix and the car is moving. For example I have the car in a Curve (you get profile, face, profile) so in this setup we have motion blur (profile) no motion blur (face) motion blur again (profile)... Anyway I will try play with frame rates and so on, but if you have any other good advises, SHOOT ! Cheers

March 22nd, 2007, 06:44 AM	#7
Gonzague Alexandre Regular Crew Join Date: May 2006 Location: Tokyo - JAPAN Posts: 43	OK I made some more test, and MAN I must be stupid.... coz I cannot get ride of this "BLUR" Please have a look at yourself and tell me what do you think... http://gagay.free.fr/video/blur.wmv this is really get me MAD... the difference between a fix or moving picture is so huge.... WHat are you settings ?

March 25th, 2007, 12:36 AM	#12
Ash Greyson Trustee Join Date: May 2003 Location: Tulsa, OK Posts: 1,689	There is no motion blur in the wmv file. You should change your shutter to 1/60 if you are in 30PN that will smooth it out. Also, make sure you turn OIS off... ash =o)

March 25th, 2007, 12:42 AM	#13
Gonzague Alexandre Regular Crew Join Date: May 2006 Location: Tokyo - JAPAN Posts: 43	Thank you Ash, but sometimes it is required in my movies (what a pompous name for what I do) to have sharp picture on fast moving cars... Yesterday I was testing the latest Nismo Z350 and drifting in Mountains, so how can I make sure to get the best picture out of this situation Cheers

March 25th, 2007, 05:52 AM	#14
R Geoff Baker Major Player Join Date: Jan 2005 Location: Ottawa, ON Posts: 471	As a rule, the shutter speed that will best match movement across the frame is the 1/frame rate. Having said that, you can expect that 1/2xframe rate will look almost natural, and 1/4xframe rate still reasonable. 'Frame rate', for the purpose of interlaced shooting, is field rate, so an NTSC shooter would describe 1/60 as normal if shooting interlaced. The speed of the motion, and the type of motion (lateral, towards, away, et cetera) will vary the definition of acceptable ... HTH GB

March 25th, 2007, 08:22 AM	#15
Gonzague Alexandre Regular Crew Join Date: May 2006 Location: Tokyo - JAPAN Posts: 43	Ok but.... on a HVX we have different shutter speed like 500, 1000 or 2000... but when you are in 30 or 60... I cannot use those higher setting ?!?!? I am confuse Lets see if I have a 500 shutter speed in order to respect a full digit rule (no number like 1.33) I must have a 25fps, 1000 a 50... How can I do that.... I am really lost here