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

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.

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.

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.

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.).

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

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 ?

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

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 ?

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

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?

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)

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

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

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

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

You can use the higher shutter speeds if you want a "Saving Private Ryan" effect. They can work with water spray when you want a sharp strobe type effects on the water droplets. However, if shooting you're at 24p, 30p or 60p the high shutter speeds should be regarded as an effect.

The standard shutter speeds are 1/48, 1/60 and 1/120 respectively, if you go higher than these you need to aware that you are increasing the jerkiness of the action.

A car moving through a static shot doesn't need a high shutter speed. You're not trying to freeze action as stills photographer does, the motion blur smooths the action.

If shooting progressive, make sure the shutter is switched on.

'Cannot' ...

You can always use high shutter speeds when the subject is motionless. And in general, if the object is moving towards or away from you, you can use much higher speeds than if the subject is moving laterally. And if the object is distant, you can use a higher speed than if it is close ...

As for the full digit rule ... I don't know where you are going with that. In general, shutter speeds are in full stop increments -- each notch halves the speed, and so drops the exposure by one full stop. But there is no rule in that -- if the speed dropped by less than half, the aperture would open a little to keep exposure accurate. 30/60/125/250/500/1000 is not essentially any different than 25/50/125/250/500/1000 ... the percentage 'jump' from 50 to 125 is mildly significant, but once done the rest of the values hold.

HTH

GB

You're better using neutral density filters for controlling exposure rather than shutter speeds.

Thanks Guy... I need to play more and to more test until I reach the perfect setting... unfortunately time is always my enemy...

Once again Thank you for your kind help

If sound is not important, I would suggest shooting 30pn with 60p slowmotion. Than speed up in post (double speed). Shutter at either 125 or 250. Try this out.

As for native 30pn, if you don't want the moving car to stutter, try Panning with the car CENTERED. The scenery will blur, but the car will stay sharp. Shutter speed of 125 should be the further you go.

And do turn OFF OIS, like the fellow DVInfo member pointed out. OIS adds a layer of blur, EDIT much noticeable in FILM LIKE Progressive frame rates- 30p, 25p or 24p . It was designed to work in Interlaced modes, EDIT or smooth progressive frames like 50p or 60p, not in film like frame rate modes.

Why would an 'Optical Image Stabilizing' system care if you were shooting interlace or not? What 'layer of blur' could the moving lens of the OIS system introduce?

Turning off OIS to smooth panning makes sense, if the OIS is sensitive to the rate of pan ... but frankly, rest sounds like nonsense ...

GB

Why would an 'Optical Image Stabilizing' system care if you were shooting interlace or not? What 'layer of blur' could the moving lens of the OIS system introduce?

Turning off OIS to smooth panning makes sense, if the OIS is sensitive to the rate of pan ... but frankly, rest sounds like nonsense ...

GB

Well, what I meant was that OIS affects image movement you're recording in a progressive mode that's bellow 60p or 50p. OIS compensation for movement seems to add a layer of compensation thats visible in these frame rates. In interlaced 60 i and 50 i footage, this is also a non-issue, due to the natural smoothness of the image. It can add a small layer of softness in pans, but not much noticeable.

That's what I meant. 60p/50p frame rates also work fine with OIS. Its just when you're working with film frame rates that OIS looks particularly bad. Saying only interlaced was my mistake. I wanted to say OIS works particularly bad in FILM LIKE frame rates, slower than 60p or 50p-make it 30p, 24p or 25p.

Nonsense?

Maybe nonsense is harsh -- I surely didn't mean to stifle discussion.

But I fail to see how an optical lens, tilting in response to axis movement of the device ... can add a layer of anything. The lens tilts in and the image is respositioned on the sensors. The sensors, and the encoder, are 'dumb' to the action of the lens -- the reason to turn the system off during a pan is mechanical ... the tilt defeats the movement of the pan momentarily, then gives up and the image jumps to the new position, then the system tries to defeat the pan, et cetera. It is only because the OIS doesn't 'know' that you intend to move the image that it fights you.

But try as I might, I can't make sense of the rest of your description of the operation of the optical image stabilizing system. It is blind to frame rates, it doesn't add layers of anything, it is a 'simple' optical mechanical device, rather like a tripod's fluid pan head ... and simply can't be responsible for the effects I understand you to be describing.

GB

Mr Baker:

Your description of the OIS system is correct, but what I mean by the "Layer of compensation" is what you describe. This adds extra strobe while panning and tilting. In 25p, 24p and 30p, this is much noticeable. In 60p/50p and 50i/60i, this is a non issue- maybe you can get a small tilt or jump from OIS compensation, but its not a major constant problem. I do not know how to give you a technical description of the effects in 25p or 24p, but the actual results are as I described. I would certainly be more than happy to post some footage about this.

If you could post footage, I'd be most interested in seeing it.

Cheers,
GB

The only blurring I saw looked like de-interlacing artifacts...or slow-mo frame blending. Every couple of frames, the image seems to ghost...step through it and watch the edge of the license plate.

If you could post footage, I'd be most interested in seeing it.

Cheers,
GB

I'll do that. Need some days tough- going abroad for some event coverage, be back in a week.

GONZAQUE,


If your problem is "shudder" related / try this link on motion / movement /
shutter / shudder etc.

http://hd24.com/dont_shudder_at_the_judder.htm


Herman.

Thanks, did not had time to play with my HVX lately, but will surely read !