I'm curious if any HV-10 owners have experienced "rolling shutter" artifacts.

This was a big issue with the HC-1 when it first came out. Basically, since the rolling shutter system was unable to expose the whole CMOS sensor instantly, you sometime wound up with slanting and distortion on fast moving objects
(sorry if I've over-simplified the problem).

Not to say anyone tossed their HC-1 because of this, but it was in fact an issue for me, most notably in event videography when flashes occured from other people's cameras. The Hc-1 never recorded a full "flash frame"--always random strips of bright and dark in the frame, even at 1/30 and 1/60 shutter
speeds.

I'm just hoping, with an HV20 on pre-order, that this camera's shutter (or the Digic DVII chip) avoids this problem.

From the lack of complaints about this issue in this forum, maybe it is much ado about nothing on my part.


Jim

No worries, then?

I'll follow up when I can actually test my HV20.



Jim

I'm still getting an HV20 ;) But yes I wouldn't mind knowing as well. I agree, the lack of comments about this with the HV10 strikes me as a "good" thing.

I believe the HV10 does suffer from rolling shutter. I have an example I can post if you like in which I did a fast (horrible!) pan past a lamp post which on the footage looks bent! I think the effect is made worse when using slower shutter speeds (mine was at 50 I think) and when the object is nearish to the camcorder. Im not sure if the progressive recording option on the HV20 will remedy this?

The HV20 manual addresses the "rolling shutter" question in the "troubleshooting" section. Basically they say that yes, on a horizontal pan, vertical objects may look like they "lean".

I think this is the only real issue holding back the HV20 from becoming truly great camera. From what I've seen of the footage posted up so far, it looks great. Still, I'm looking at selling my HC1 to buy one of these to use until I can afford an XHA1.

As I understand it the rolling shutter effects all CMOS based cameras. I think it may be one of those things you have to "work" with.

I noticed it in some of my footage, it's only really really noticable if the camera is moving fast and the shutter speed is high (running at 1/500) I could notice it a lot more than at 1/60

An interesting, and unpleasant aritifact of the rolling shutter can be caused by a photo flash. If you are shooting with the HV10 at a time when other people are taking still pictues with a flash you will get the flash split across 2 frames. (not sure how fields enters into this). I was recently reviewing some video when a flash had gone off. The top part of frame 1 was clear and correct, the bottom part was washed out from the flash. On frame 2, the top was white and the bottom OK.

The effect of the segmented image seem a bit more jarring that what you expect from a CCD I found it quite annoying.

I saw this effect while viewing the video in FCP, so I am not sure if the visual impact would be less viewed on an interlacted TV.

Rick

As promised, here are frames from an HV20 showing what happens
when recording a strobe light (my rebel XT flash) with a rolling shutter.

For comparison, I recorded the same frames with an Elura, which is a
CCD camera and uses a different shutter system. You can see the Elura
records a clean full frame of strobe exposure. The HV20 cannot do this.

It seems this is an annoying limitation of CMOS camcorders for now. That said, however, I am so thrilled with capabilities of this camera, and see Canon bringing more of its larger frame Cmos technology to consumer videography.

One simple question. At what shutter speed was the video with the black bars taken ? It looks like it is probably the first shutter faster than the speed at which there is no problem (if you are using a flash).

Please try again with faster shutter (larger black bar) and slower shutter (no bar I hope).

One simple question. At what shutter speed was the video with the black bars taken ? It looks like it is probably the first shutter faster than the speed at which there is no problem (if you are using a flash).

Please try again with faster shutter (larger black bar) and slower shutter (no bar I hope).

Yes, I realize this needs to be tested w/ a range of shutter speeds.
I will try to post more images covering this.

For clarification, in the currently posted images, the Elura's shutter speed was set to 1/60.
The HV20 was 1/48 in 24P mode. The flash was in pre-flash mode (red-eye reduction) where it flicker-strobes for about eight video frames.
All of the Elura frames were cleanly illuminated by the strobe, while most of the HV20 frames had the black bar at various frame heights.

As I said, I will try to post more accurate data, because this might be of
interest to anyone shooting events where flashes or strobes occur, but I also don't want to get too overtly focused on a technical limitation that is invisible 97.5% of the time. I'm still quite enamored of my HV20. ;)

If I may throw this in, you know what I like most about this camera (after flawless 24p)--its the reds. After 1 1/2 years with a sony HC-1, I love that red is red.




Jim

UGH... I've seen "rolling shutter" on an HC1 (flash on top and bottom of consecutive frames, only really noticeable if you're scrolling frame by frame), and the stretch/tilt if you move your cam around too fast...

BUT those black bars are horrid! What settings was the HV20 at to get that? It looks more like a bad head clog than "rs" - I'm sure it isn't, but it would make any footage unusable - not a good wedding camera if this is how the Canon handles flash... can't imagine a glitch like this got past engineering.

How many frames are affected? Just one, or several? IOW, in normal playback does this show, or just frame by frame?

I get my HV20 today and I'm going to try and do some tests with a fan and discover at what point and what settings problems happen.

Yes, I realize this needs to be tested w/ a range of shutter speeds.
I will try to post more images covering this.

For clarification, in the currently posted images, the Elura's shutter speed was set to 1/60.
The HV20 was 1/48 in 24P mode. The flash was in pre-flash mode (red-eye reduction) where it flicker-strobes for about eight video frames.
All of the Elura frames were cleanly illuminated by the strobe, while most of the HV20 frames had the black bar at various frame heights.

As I said, I will try to post more accurate data, because this might be of
interest to anyone shooting events where flashes or strobes occur, but I also don't want to get too overtly focused on a technical limitation that is invisible 97.5% of the time. I'm still quite enamored of my HV20. ;)

If I may throw this in, you know what I like most about this camera (after flawless 24p)--its the reds. After 1 1/2 years with a sony HC-1, I love that red is red.




Jim

Here is a link to a mt2 file showing the DSLR flash strobe recorded at various
shutter speeds at both 24pf and 60i. The clip starts off with an older
CCD miniDV camera (Canon Elura) recording the same event. The Elura records the event cleanly. The HV20 records hard banding at every shutter speed, even the slow speeds. This still is not a scientific test, but I think it
demonstrates that clean records of standard camera flashes are not likely
with this camera--another limitation of the Cmos rolling shutter. I did get a
clean flash once in 60i at one-thirtieth shutter, but I could not repeat this--it
seems to be due random timing luck.

I guess some math could be done to correllate the "rolling" shutter timing with
the adjustable electronic shutter, to fully explain the banding patterns and
perhaps find a sweet spot for the cleanest recording of strobes and camera flashes.


http://www.sharebigfile.com/file/138581/HV20RollingShutterTest-m2t.html

The file is 117mb mt2 reduced to 720 30p.



Jim

CMOS rolling shutter.. yes.. it occurs. Smooth pans and tilts are best - with hand-held work, you'll notice it. On a tripod, if you respect the audience (and pan and tilt nice and smoothly) it'll be fine. You work with the camera, not agianst it. I own an HV20.. getting a new Manfrotto tripod to match up with the camera.

It seems to me that this is MORE than "rolling shutter" - trying to download the video, looks like it's not responding at the moment - comes up with a can't display the webpage message... guess lots of others are trying to download at the same time! The download counter IS ticking up pretty fast!

Rolling shutter gives some wacky stretched or leaning video and the split frame flash effect - annoying, but a tripod or stabilizer solves problem #1 and the other is not THAT annoying, just a bit of a shock the first time you see it...

Major black bands across the frame represent a BIG issue if it is visible in the video... hoping to look at the video if the server will let me at it. Those stills if they represent what happens when a flash goes off while shooting would pretty much render this camera useless or at least severely impaired in any environment where flash cameras were in use IMO. Weddings? School plays? Birthday parties?

ANYONE ELSE with an HV20 tried replicating this "effect"? I can't imagine this slipped past testing - seems too common a scenario for use of a video camera... maybe it's a bad unit?

Only other explanation would be how Canon addresses the chip - maybe changed from "top/bottom" to a banded addressing? I could see how this might cause "50%" of the frame to be temporarlily "blinded". Flash does tend to cause problems with ANY camera... but this would be extreme and a major "flaw" in the design if it's reproduceable. Really hope it's a random glitch... hearing too many great things about this camera!

DB>)

Get VLCPLAYER at www.videolan.org, download my 5 minute footage I shot this weekend and temporarily forget about rolling shutter. I certainly don't see it and I had some pretty fast shutter rates in the shots 1/1000. I was worried I might see bizarre rolling shutter artifacts with my water fountain shots but they are "not there". Yes, maybe a flash from a camera shows it, but I haven't seen anything yet in things I've shot that is "noticeable".

To Mark and all the others who are showing us fantastic HV20 footage,
I agree that this camera is a phenomenal imaging device, and I don't want anyone to think I'm exaggerating what is truly a marginal weakness. Believe me, I haven't just been shooting flash frames with the camera. ;)

I do think, however, that anyone hired to shoot a wedding reception using an HV20 (or any CMOS camera) should be certainly aware of the shutter limitations,
and try testing it for themselves.

Now I have to go and put up some nice daylight 24p clips to undo any harm
caused in this thread. ;)

Hi James -
Still hoping to download your sample - counter keeps going up and up, so I guess others are interested in this too! I'll just keep trying... until the server melts down...

I have been looking at this camera myself, based on some great video it obviously shoots under MOST conditions. The 24p feature is interesting too, I've shot with Panasonics with frame mode, and liked the results.

I've seen "rolling shutter" on my Sony CMOS cams, it imposes some additional hurdles (see above), but I've NEVER seen anything that looked like the banding in your stills. It would pretty much make the video unusable IMO, so it IS an issue if one is going to be shooting in the presence of stll camera flash... really would be good to know if others can replicate it.

A flash appearing on the top of one frame and the bottom of the next is annoying, but not "fatal" - 50% of the image going black in "bands" is another matter. I know I would not want to shoot a critical event and later discover this... can't see a consumer (who is MORE likely to be be using the cam at events with flash) accepting it either. Probably will make for lots of "repair"/returns at BB and CC...

I'm hoping you've just got a bunk cam... or the video won't really be as noticeable.

Dave, in actuality all CMOS camcorders have the same rolling shutter effect. To be honest, I've never seen it on my Sonys or Canons. You have to shoot under the 'right' conditions to see it.

Dave,

The stills are scarier than the video because you are staring at them. ;)
You'll have to test the camera yourself to get a feel for the banding--but
the partial exposure of flash frames IS quite noticable at 24p and 60i frame rates.

But then again, as the collective wisdom of this forum has pointed out, most of time we are shooting something other than camera flashes.

Final thoughts:

1) The HV20 also is a still cam--with a flash. I would NOT expect to see "banding" in this mode (but have not confirmed this), yet the image still must be exposed with the same rolling shutter. So it is possible to sync in this
special case (if only with the on-board LED).

2) If you are going to shoot an event with alot of other "paparazzi", your best chance for random frame sync with off-camera flashes (while maxmizing low light and having "acceptable" motion blur) is Tv = 1/24 for 24pf, or 1/30 for 60i. Otherwise, you can rent a CCD based camera like the XH A1. ;)

Jim

It seems to me that this is MORE than "rolling shutter"

No. That's exactly what rolling shutter does when flashes go off. Same thing with the hc1. What's pretty much weird is that there is not much mention of the V1 having this problem or not.

Hi Ken -
I've seen enough samples/examples of "rs" to know it's a CMOS issue - guess it's just not possible to address the entire chip at a single fraction of a second in time (yet?). Probably a processor speed issue, reminds me of the challenges in guitar synth note aquisition...

I've seen the "split flash" thing a few times, and it is NOT 100% of the time - probably a matter of timing being just right (wrong?).

The vertical stretch and lean thing is also something I managed to replicate by accident when first shooting with the cam - it's too fast pans or too fast up and down motion. Harder to avoid than with SD/CCd cams, but just a matter of being careful. Sloppy camera technique when one really considers it!

What's got me is the stills James posted earlier in this thread (still can't download his video, server is overloaded I guess...). Those stills show not a "washed out half frame" (split flash), but SEVERE black banding throughout the whole frame - quite literally half the information simply is GONE, by those .jpgs. THAT would be a deal killer if there's not a workaround - every wannabe photographer has a mini-digital/phone/pocket/disposable camera with a flash these days... and they aren't afraid to use them... so there's a high probability that there WILL be flash at any event that you might video.

I just can't see how the banding could be anything other than a one off glitch (anyone else REPLICATE this?), but if it's not, it would be one huge problem...

Like I said, how many soccer moms are going to buy this cam because Canon says how cool it is to shoot Biff and Betsy in Hi Def and go totally freakazoid if/when those black bands flash across the old wide screen??

I won't complain if it is a design flaw, maybe it'll make it easy to pick up a "slightly used" unit cheap for the things it does EXTREMELY well <wink>! The CCI review was enough to help a couple practically new HC7's drop into my lap... and I sure don't have any complaints with them, even in very low light!!

Take a look at those stills and see what you think... I'm STILL waiting to get through to the video...

No. That's exactly what rolling shutter does when flashes go off. Same thing with the hc1. What's pretty much weird is that there is not much mention of the V1 having this problem or not.

Hi Mikko -

Look at the stills James posted... I'm still waiting to see the video.

I've NEVER seen anything like that black banding on my HC1 - split flash, vertical compression/stretch, yes, but nothing like THAT.

There was in fact a thread a while back where someone using I believe an FX7(same optics/CMOS as V1) had the spilt flash thing well illustrated... as a wedding videographer, it was not a happy discovery for him. I've seen it enough to be annoyed, but it's not as I said "fatal". I've never had a section of video with black stripes, just some macroblocking (any camera will get that), and the split flash. BIG difference in my book. Maybe I've missed something, but those stills don't seem right to me...

Dave, as I said, I've never ever (not once) seen this in moving video. In fact, I can't think of other owners of the HV10 or HV20 complaining about it. So I think this is much ado about nothing. Let's face it, if this was anywhere near as severe as you think it is, people would be screaming bloody murder. Instead you just see people raving about picture quality.

There's also nothing in the design of the CMOS sensor in the Canons that would make it more or less prone to this than any Sony cam equipped with a CMOS sensor.

Fear not, fear not! :)

Hi Ken -
That's what I'm thinking too. I think James may have a bunk unit? There are always early production bugs to work out... and users have to figure out the fidgety bits of any new toy.

Have you done anything with a flash going off, just as a "second opinion"? Any chance you could if you haven't, just for giggles?

Since this intrigued me, I took a few moments to fire off a few shots with the HC7 - in slow shutter mode, fairly dark closet, camera could see better than I could, redeye and normal flash looked pretty much normal - only once did I get a half and half frame out of around 10 shots. At 60 shutter, I got the bottom half of the frame on every preflash, and full frame flash on the main flash... Some macroblocking as the camera adapted, as expected, but run at normal speed it looked fine considering. Timing does affect what shows up as far as the flash.

I'm still puzzled by those HV20 stills with the black banding... does the Canon in fact roll the addressing on the CMOS in "bands" (rather than top/bottom or top to bottom) so as to minimize RS under "normal" conditions, and with the flash that could cause this issue? It sort of makes sense to address the chip that way to minimize rs effect, but it may introduce other issues.

My first HV20's lens protector did not open all the time so there are defective units out there.

Hi Mikko -
There was in fact a thread a while back where someone using I believe an FX7(same optics/CMOS as V1) had the spilt flash thing well illustrated... as a wedding videographer, it was not a happy discovery for him. I've seen it enough to be annoyed, but it's not as I said "fatal"

Keep in mind, we’re talking about HDV cameras here.

I've shot 70 tapes on Sony Z1U and FX1 combined - these "imaging" problems occur, in a different manner. Take a look at the attachment - that's the SONY FX1 dealing with a) a bright light (CCD streaking) and b) HDV trying to compress something it didn’t expect. This “flash” image is 2 frames after the original flash went off ;) Imaging limitations in HDV and CCDs and CMOS sensors aren’t new.

On my HV20, I quickly noticed the CMOS lag when I moved quickly horizontally and vertically. The frame leans on fast pans, and squishes/stretches on fast tilts. I noticed quickly due to the wide-angle lens I had on: the vignetting lens that was attached stayed the same, while the image in the background moved oddly - I could visually see what a static object behaved like while I saw what the background - fast movement - acted like.

Yes, it's there - it always will be. It's not Canon's fault, it's me being too observant and the fact that CMOS is the way it is. I'll WORK around it/with it. It's good to be aware.. like I said, transcribing reality to a visual medium such as a still picture, or a moving picture - video - requires a lot of compromises and work arounds. Light for instance - the camera needs more to see things as we would - we work with that. Etc.

Learn to live with it - this is simply an early camera - notice more CMOS cameras as they arrive, and I'm sure the tech one day will enhance the sensor. Until then, enjoy what you have - I feel lucky to have a Camera THIS good! 10 years ago, this was a dream that I would have thought would take 20 years to reach.

We've all moved on to more important issues, but
after rereading this long-deceased thread, I finally realized that some people
thought my HV20 was defective due to solid black bars in the flash frames, whereas those bars were really just underexposed due to CMOS you-know-what.