Image Stabilization Issues?

Ken Ross · March 26th, 2007, 06:45 AM

Quote:

Originally Posted by Hal Snook

So, just to be clear, all of you saying this is in the realm of normal have looked at the footage Austin included in the original post?

Absolutely not. I've never seen OIS behave that way and it certainly doesn't on my HV10 or HV20 or any other OIS camera I've ever had. I'm not sure what the issue is there.

Ron Lemming · March 26th, 2007, 07:34 AM

I also got the feeling that all of you that has posted here saying it's normal didn't really watch the footage. It doesn't look right at all.

Ken Ross: Good to know that not all HV20s behave like this.

Mike Dulay · March 26th, 2007, 07:53 AM

Ken, just want to clarify that you are able to go from standing to sitting and perhaps walk with the image holding reasonably within around the subject? You are doing this full wide right? Please tell me its true.

I'm one of those watching and waiting for feedback on the HV20 before comitting. 8-) I use a camcorder for vacation and sports in a run-and-gun style (real amateur style). My personal expectation is a camcorder wouldn't be too jittery at full wide while following after a walking person or holding the camera with one hand while braced would be fairly still. At any zoom setting I wouldn't expect the OIS to work well.

Chris raised an interesting point on reasonable expectations for the OIS. I bought the original Elura (also with OIS) years ago knowing its limitations. I shoot with the camcorder close to face or very close to the body to try to keep it stable. When I run around I use my tripod like an adhoc steadicam. If I understand it correctly, the small size and light weight of the HV20 contributes to shaky movements which reflect easier on the image because of its increased resolution. So it becomes a question of ballast. I'm curious to hear what people are able to do reasonably with the OIS sans tripod/steadicam.

Kevin Samborn · March 26th, 2007, 03:56 PM

OK, in my other thread about Cine Mode, I mentioned that I experienced a similar "ripple" in the recording - though no where near as severe. I will post a sample when I can.

However, I wonder if it is a matter of the heads being cleaned?

The manual says this on page 94:

--

- During playback you notice frequent video problems (blocky video artifacts, banding, etc.)
- When playing back a tape recorded in HDV standard the playback is jerky or the sound stutters on and off

--

and, on page 26:

--

Before you begin recording
Make a test recording first to check if the camcorder operates correctly. If necessary, clean the video heads

--

Kevin

Ken Ross · March 26th, 2007, 03:59 PM

Mike, I'm not saying that you would be able to walk around, run around or go from a sit to a stand position and have the image stay absolutely stable. That's not how OIS is designed. What I was commenting about was the video that showed an odd 'bending' which I haven't seen before. But if I were to walk or run holding the camera tight to my body, I would fully expect a shaky image.

As Chris and I have pointed out, it's designed to stabilize small hand movements which are expected when hand holding a camera. The efficacy of OIS can be seen by simply using the telephoto at some arbitrary length and watching the image with and without OIS. Without OIS the image is almost unwatchable with small hand movements being magnified. With OIS engaged, the image can be very steady depending upon how steadily you hold the camera to begin with.

Austin Meyers · March 27th, 2007, 11:18 PM

so i didn't return the camera after hearing what yall had to say. also i just discovered that shooting in 60i produces much steadier footage than shooting 24p. i'm new to 24p and that never crossed my mind that that could be an issue. just to reiterate when it's in 60i it performs as i orginally expected it to, ie. you can walk around and use it handheld and the footage is more than useable.

is having more shake common in other cams that shoot 24p? i know because there are 25% more frames that it tends to smooth things out in 60i but i never imagined the difference would be so pronounced.

if anyone is interested i can post up some moving footage of the 24 vs 60.

i'll also have some other 60i footage i'll be throwing up pretty soon...

George Anthonisen · March 30th, 2007, 06:01 AM

The 24p that people are going crazy over, first of all is not the same kind of 24p that you will see on film. Secondly, there is an art to shooting in 24p. You can't really shoot it reliably without a tripod. The slower frame rate is very good at picking out and even amplifying camera shake. There is more time BETWEEN frames because of the lower frame rate so fast movements come across as being "jerky". It's much the same as slowing down a strobe light on the dance floor... more off time allows there to be larger movement of the arm (for example) in the darkness. Camera shake due to walking can be classified as FAST movement. You're talking maybe a few milliseconds worth of movement (from the onset of a cam shake episode to its end) that reverberates through the cam with a simple step. So the result is that you will most likely capture the start of the camera shake episode and maybe the ending of that episode... but everything in between is missing... hence... the extreme jerky look. Now multiply that by the number of steps you take in a minute... throw the progressive behavior (as opposed to interlaced) into the mix.... and you have a real mess on your hands.

And THAT'S the other biggy... the progressive scan vs interlaced, which even gets more complicated... but the bottom line is that it will all translate into slower, more even movements required.

I've said this before on another sight... this 24p seems to be a big selling point for this cam and most people are going to be disappointed with it when they get it home and try it. 60i is very forgiving stuff when it comes to cam shake, fast pans, and other jerky movements... but 24p is not. Most people are going to try this once or twice, then forget about it.

So, in 60i you SHOULD be able to walk softly and have the video come out like any other cam in its class... but with the 24p, put the cam on a fluid tripod and try some slow even pans, and see what you get, before you make any big judgment calls

Ken Ross · March 30th, 2007, 06:52 AM

And in actuality, the HV20 can sell itself without the 24p mode. The video at 60i is simply that good.

Peter J Alessandria · March 30th, 2007, 08:45 AM

Don't mean to be too contrarian George, but thousands of us have been shooting with DVX100's/XL 2's in 24P for years, handheld, run 'n gun, without tripods, etc. with excellent results. The strobing problem you mention is most evident I think, ironically when panning too fast on a tripod. On the other hand, I've done all kinds of fast moves on my DVX100 without any real issues (also shooting in 24pA [advanced mode] exacerbates a strobing effect regardless of whether the camera is moving or not). You're right - 24p video isn't the same as 24 fps using film. But I don't think the OP's problems have anything to do with shooting 24p or not.

Javier Gallen · March 30th, 2007, 04:23 PM

That image distortion seems to be produced by the combination of high shutter speeds and very fast camera moves. In the same way, some photo cameras do tricks in order to achive high shutter speeds that cause temporal image distortion. For example: If you take a picture of trees when travel in a car, they may appear oblique instead of vertical. All because of a particular high shutter speed design.

I read this camera uses a 360º shutter. THAT, and the combination of high speed shutter preset and fast camera moves results in a unnavoidable image distortion.

Even so, that is far of being a real problem. Just waiting for the PAL release.

Dennis Vogel · April 4th, 2007, 07:41 PM

Quote:

Originally Posted by Matt Buys

I shot some footage with the HV20 and an Elura side by side and I came to the conclusion that because the HV20 was so much sharper, you "noticed" jitteryness more.

I think this is the biggest factor at work here. Camera movement and focus problems are both so much more obvious with HDV. Many folks think shooting HDV is just like shooting DV but there are some subtle differences due to the huge increase in resolution. You have to learn to work with HDV.

Good luck.

Dennis

Povl H. Pedersen · April 5th, 2007, 02:40 AM

The distortion Galen is talking about is that with a digicam, when you hit a shutter speed faster than the sync speed (1/60s - 1/250s typical dependent on camera), then the whole sensor is not exposed at once. Instead a top shutter and a bottom shutter (called curtains) are move over the sensor with a little opening between.

If we assume a sync speed of 1/100s, then a shutter speed of 1/1000s means that only 1/10th of the shutter is exposed to light at any given time. It also means, that there is a time delay of 1/100s between the exposure at top and at bottom.

This can give warped pictures.

It also means, you can not use a flash unless it is in FP mode, otherwise only part of the image will see the flash. So the flash is set to pulse for the 1/100s.

March 26th, 2007, 07:53 AM	#18
Mike Dulay Major Player Join Date: Mar 2007 Location: Somerville, NJ Posts: 304	Interested parties want to know Ken, just want to clarify that you are able to go from standing to sitting and perhaps walk with the image holding reasonably within around the subject? You are doing this full wide right? Please tell me its true. I'm one of those watching and waiting for feedback on the HV20 before comitting. 8-) I use a camcorder for vacation and sports in a run-and-gun style (real amateur style). My personal expectation is a camcorder wouldn't be too jittery at full wide while following after a walking person or holding the camera with one hand while braced would be fairly still. At any zoom setting I wouldn't expect the OIS to work well. Chris raised an interesting point on reasonable expectations for the OIS. I bought the original Elura (also with OIS) years ago knowing its limitations. I shoot with the camcorder close to face or very close to the body to try to keep it stable. When I run around I use my tripod like an adhoc steadicam. If I understand it correctly, the small size and light weight of the HV20 contributes to shaky movements which reflect easier on the image because of its increased resolution. So it becomes a question of ballast. I'm curious to hear what people are able to do reasonably with the OIS sans tripod/steadicam. __________________ DIY, 35mm, HV20: http://www.primitivebuteffective.net

March 27th, 2007, 11:18 PM	#21
Austin Meyers Contributor Join Date: Aug 2005 Location: austin, tx Posts: 300	update 24p vs 60i so i didn't return the camera after hearing what yall had to say. also i just discovered that shooting in 60i produces much steadier footage than shooting 24p. i'm new to 24p and that never crossed my mind that that could be an issue. just to reiterate when it's in 60i it performs as i orginally expected it to, ie. you can walk around and use it handheld and the footage is more than useable. is having more shake common in other cams that shoot 24p? i know because there are 25% more frames that it tends to smooth things out in 60i but i never imagined the difference would be so pronounced. if anyone is interested i can post up some moving footage of the 24 vs 60. i'll also have some other 60i footage i'll be throwing up pretty soon... __________________ Compositing is my life right now. IMDB page: http://www.imdb.com/name/nm3596782/

March 30th, 2007, 08:45 AM	#24
Peter J Alessandria Major Player Join Date: Oct 2003 Location: Los Angeles, CA Posts: 293	Don't mean to be too contrarian George, but thousands of us have been shooting with DVX100's/XL 2's in 24P for years, handheld, run 'n gun, without tripods, etc. with excellent results. The strobing problem you mention is most evident I think, ironically when panning too fast on a tripod. On the other hand, I've done all kinds of fast moves on my DVX100 without any real issues (also shooting in 24pA [advanced mode] exacerbates a strobing effect regardless of whether the camera is moving or not). You're right - 24p video isn't the same as 24 fps using film. But I don't think the OP's problems have anything to do with shooting 24p or not. Last edited by Peter J Alessandria; March 30th, 2007 at 06:31 PM.

March 26th, 2007, 07:34 AM	#17
Ron Lemming Regular Crew Join Date: Oct 2006 Location: Sweden Posts: 46	I also got the feeling that all of you that has posted here saying it's normal didn't really watch the footage. It doesn't look right at all. Ken Ross: Good to know that not all HV20s behave like this.

March 26th, 2007, 03:56 PM	#19
Kevin Samborn New Boot Join Date: Apr 2006 Location: Swampscott, MA Posts: 14	OK, in my other thread about Cine Mode, I mentioned that I experienced a similar "ripple" in the recording - though no where near as severe. I will post a sample when I can. However, I wonder if it is a matter of the heads being cleaned? The manual says this on page 94: -- - During playback you notice frequent video problems (blocky video artifacts, banding, etc.) - When playing back a tape recorded in HDV standard the playback is jerky or the sound stutters on and off -- and, on page 26: -- Before you begin recording Make a test recording first to check if the camcorder operates correctly. If necessary, clean the video heads -- Kevin

March 26th, 2007, 03:59 PM	#20
Ken Ross Trustee Join Date: Jan 2005 Location: New York Posts: 1,945	Mike, I'm not saying that you would be able to walk around, run around or go from a sit to a stand position and have the image stay absolutely stable. That's not how OIS is designed. What I was commenting about was the video that showed an odd 'bending' which I haven't seen before. But if I were to walk or run holding the camera tight to my body, I would fully expect a shaky image. As Chris and I have pointed out, it's designed to stabilize small hand movements which are expected when hand holding a camera. The efficacy of OIS can be seen by simply using the telephoto at some arbitrary length and watching the image with and without OIS. Without OIS the image is almost unwatchable with small hand movements being magnified. With OIS engaged, the image can be very steady depending upon how steadily you hold the camera to begin with.

March 30th, 2007, 06:01 AM	#22
George Anthonisen Regular Crew Join Date: Mar 2007 Location: Winnipeg Canada Posts: 51	The 24p that people are going crazy over, first of all is not the same kind of 24p that you will see on film. Secondly, there is an art to shooting in 24p. You can't really shoot it reliably without a tripod. The slower frame rate is very good at picking out and even amplifying camera shake. There is more time BETWEEN frames because of the lower frame rate so fast movements come across as being "jerky". It's much the same as slowing down a strobe light on the dance floor... more off time allows there to be larger movement of the arm (for example) in the darkness. Camera shake due to walking can be classified as FAST movement. You're talking maybe a few milliseconds worth of movement (from the onset of a cam shake episode to its end) that reverberates through the cam with a simple step. So the result is that you will most likely capture the start of the camera shake episode and maybe the ending of that episode... but everything in between is missing... hence... the extreme jerky look. Now multiply that by the number of steps you take in a minute... throw the progressive behavior (as opposed to interlaced) into the mix.... and you have a real mess on your hands. And THAT'S the other biggy... the progressive scan vs interlaced, which even gets more complicated... but the bottom line is that it will all translate into slower, more even movements required. I've said this before on another sight... this 24p seems to be a big selling point for this cam and most people are going to be disappointed with it when they get it home and try it. 60i is very forgiving stuff when it comes to cam shake, fast pans, and other jerky movements... but 24p is not. Most people are going to try this once or twice, then forget about it. So, in 60i you SHOULD be able to walk softly and have the video come out like any other cam in its class... but with the 24p, put the cam on a fluid tripod and try some slow even pans, and see what you get, before you make any big judgment calls

March 30th, 2007, 06:52 AM	#23
Ken Ross Trustee Join Date: Jan 2005 Location: New York Posts: 1,945	And in actuality, the HV20 can sell itself without the 24p mode. The video at 60i is simply that good.

March 30th, 2007, 04:23 PM	#25
Javier Gallen Regular Crew Join Date: Jul 2005 Location: Spain Posts: 67	That image distortion seems to be produced by the combination of high shutter speeds and very fast camera moves. In the same way, some photo cameras do tricks in order to achive high shutter speeds that cause temporal image distortion. For example: If you take a picture of trees when travel in a car, they may appear oblique instead of vertical. All because of a particular high shutter speed design. I read this camera uses a 360º shutter. THAT, and the combination of high speed shutter preset and fast camera moves results in a unnavoidable image distortion. Even so, that is far of being a real problem. Just waiting for the PAL release.

April 5th, 2007, 02:40 AM	#27
Povl H. Pedersen Regular Crew Join Date: Mar 2007 Location: Aarhus, Denmark Posts: 28	The distortion Galen is talking about is that with a digicam, when you hit a shutter speed faster than the sync speed (1/60s - 1/250s typical dependent on camera), then the whole sensor is not exposed at once. Instead a top shutter and a bottom shutter (called curtains) are move over the sensor with a little opening between. If we assume a sync speed of 1/100s, then a shutter speed of 1/1000s means that only 1/10th of the shutter is exposed to light at any given time. It also means, that there is a time delay of 1/100s between the exposure at top and at bottom. This can give warped pictures. It also means, you can not use a flash unless it is in FP mode, otherwise only part of the image will see the flash. So the flash is set to pulse for the 1/100s.