GL2 / XM2 Frame mode
 

Jerkiness or Strobing in GL2 Frame mode

Several people with PAL GL2s have reported jerky images when panning in Frame mode, at their 25fps rate. What has been the experience regarding this from those who are shooting in Frame mode with NTSC GL2s with 30fps? Is this glitch diminished by the higher frame-rate? I wonder if true progressive-scanning cameras, like the AG-DVX100, have such a pronounced problem with jerkiness when panning?

This is a "feature" of any progressive scan (or in the case of Canon it's pseudo-progressive scan) video camcorder. Camera movements must be done sloooowly, cinematic style. On the Panasonic DVX100 it's even more pronounced due to the slower frame rate.

Steve

Regarding the NTSC gl2, I use the frame mode exclusively and I almost never see a problem. 90% of the time its when I'm just not paying attention to how I'm shooting, or if I'm trying to hand hold without a proper support--essentially bad camera work to start with.

Here's a clip that has a lot of movement (shot on a gl1--which I think uses a slightly less smooth version of the frame mode), I don't think there is much of a problem anywhere.

http://homepage.mac.com/barrygoyette/iMovieTheater4.html

And some tips(which you may have already read)

http://www.dvinfo.net/conf/showthread.php?s=&postid=20690

Barry

I'm pretty sure that the XM2 is worse at this then the GL2. I panned really slooooow last night in frame mode and I still got the jitter really badly. It's just not usable at all I'm not just being fussy. The one thing I didn't try was to to put the shutter at 1/25 because in normal mode this makes it jerky so I didn't even think of trying it in anything less then 1/50 but I will give 1/25 a go as well but I have a feeling it will make it worse not better.


Peter B

Peter..

try this...Its just a hunch (I haven't tried it yet):

Do a custom preset with the sharpness turned all the way down, and a setup of +1 or +2, this might lessen the problem. I noticed yesterday while panning a picket fence (yikes) that if I took the image a little out of focus, it didn't strobe, not even a little. Maybe softening the edge will do the same thing...its worth a shot. If it works, then you could experiment with increasing the sharpness till it hits the sweet spot.

Barry

Sounds like an idea, I'm leaving work now so I'll post tomorrow to tell my results. Seriously though the effect at the moment is similar to the strobe effect in effects mode...ok not that bad but pretty close.

One other tip is if you are shooting from a tripod, make sure the image stabilizer is off.

Ok I had a go last night and did get a better result. I turned the sharpness down and the setup a little bit up. It gave a lot smoother result but I don't think you could use it to do chase scenes like Barry did in his. If you zoom in and out it's perfect you can't detect it at all but panning slowley still gives a slight jitter, but it is more of a jitter then a jolt or the strobe effect. Im going to try it in better light as well because so far it's always been in indoor lighting. I work late so don't get back before 8:00 but I'll try over the weekend.


Peter B

my favorite frame mode setting is with shutter at 1/25th
If you move the camera fast enough that it looks strobey, the image blurs because the shutter is open for so long. This blur greatly reduces the amount of strobe perceived by the viewer, and looks cool & filmy!

I tried it on my skateboard yesterday, the result looked great.

I also tried it with shutter on 1/800, and the image was so sharp & fast moving it made my friend feel ill!

The only problem is if you're shooting stuff of varied speed for example a documentry or short film I feel that it would just hinder your creativity always having to worry about what shot you can have and at what speed just for that filmic look. I'd rather work on the lighting to get the film look and let my creativity run free not becoming frustrated when a shot I know would look really cool can't be used because it would jitter.


Peter B

For what it's worth, Peter, I tried turning down the sharpness on my gl2, and I'm pretty amazed at how much any hint of stuttering has gone away. I shot some more footage yesterday of Kaori running through the forest, all hand held, with some pretty questionable camera work, and everything looked just fine. I know this doesn't help xm2 owners, but I thought this might be of interest to those using the ntsc version. I'm hoping that your normal daylight tests will give you better results, as I can't see why the xm2 (even with the lower framerate) would be vastly different from the gl2.

One thing that I've noticed over the years is that some of the jumpiness can be attributed to the output device (monitor), cabling and other things...I don't know the technical aspects of it, but video signals can be sensitive to a lot of things, and I've seen the jumpiness of certain footage vary from set to set (and be almost non existent on a computer monitor).

Barry

"Several people with PAL GL2s have reported jerky images when panning in Frame mode, at their 25fps rate."

FILM at 24/25 fps has the same "jerkyness" .

" I wonder if true progressive-scanning cameras, like the AG-DVX100, have such a pronounced problem with jerkiness when panning"

it will have it's OWN jerkyness. remember this camera lays down to tape at 60i ( in 24p mode) .just like when film is transferred to NTSC it adds the 3:2 pull down .. this camera does the same 3:2 ( or the new 2:3) in the end it is 60i on tape ..and you view 60i watching the tape on a monitor ..

Tried it in daylight with the sharpness turned down, it's better but you still get a weird effect. But you're right about if you pan fast you don't notice it. To be honest I don't think I'll be using it, I prefer the normal mode, nice to have the option though.

Peter

One final note. I went to see "The Kid Stays in the Picture" yesterday. It's a documentary about the life of producer Robert Evans and made a lot of use of motion control on still photos, newspaper clips etc, in addition to vintage footage and some contemporary steadicammed interior and exterior shots of his house.

Looked like it was shot on 16mm, but maybe 35mm. Anyway I noticed that some of the shots of newspaper headlines, and high contrast bw photos panning across the screen strobed as bad (actually worse) than similar high-contrast images on my canon cameras, yet other motion control stuff of lower contrast had no such problem. It makes me think that perhaps these video cameras aren't that different from film in the first place, and perhaps contrast (and sharpness) is the real issue. I've noticed similar high contrast strobing in several feature films lately (on television), as well.

It's very easy with these camera's to make them strobe, by panning the camera against a varied background and viewing the results...and while this is not an unusual camera movement, pans like this often involve a moving subject, which typically remains relatively stationary in the frame. I encourage you to experiment with shots like these (following a person walking, a car, skateboarder) to see if you still notice the problem. Also, try Chris's recommendation and mount the camera on a tripod, and let someone move with in the frame..or just film an interview. See what you think.

If you don't like the look, then certainly don't use it. I'm a big proponent of the frame mode because I don't like the look of typical ntsc interlaced video(otherwise I'd probably own a sony). I guess I'm having a hard time believing that the pal camera is significantly different from the ntsc version, and is, in effect, unusable. In my experience, camera work is almost always the culprit. But regardless, I appreciate the discussion as I have learned alot from it. (In fact, the sharpness adjustment has virtually eliminated even the slightest amount of jitteryness with my camera). Thanks for bringing it up.

It's Labor Day here, so I guess I'll head off to work (my boss is an a**hole). cheers!

Barry

True I mean all my experimental stuff has been me just panning the camera across the garden. Also if you have a subject to focus on then it draws your attention away from the background so I guess that would help a lot and like you say they won't be moving that much in the frame. I'll see I will carry trying things out. I don't have a problem with the way Pal interlaced looks though and on the XM2 to it still has quite a filmic look to it.
Nice comment on the end by the way Barry, very out of context but very funny.

Frame Mode + post special effects
 

I remember reading somewhere here that frame mode was a no no if you intended to do sfx in post - is that true, and why?

As far as I can see, it wouldn't really be a problem if you knew what you were doing. Or perhaps they meant frame mode was a bad idea if you intended to transfer to film?

Alex

In my opinion shooting in frame mode increases your ability
to do post production. But it all depends on what you like and
how you think things look. EXPERIMENT!! Do not blindly follow
other peoples instructions but try them out and see what works
best for you. Frame mode looses some image quality that might
degrade your post work, however, it also removes interlacing
problems.

Whether or not frame mode is bad to process to film depends
entirely on the house that does that conversion. Some prefer
interlaced footage while others prefer progressive. Make sure
you inquire with them before shooting.

Personally I'm not caring for film distribution because there is
very little chance that I'll do that. My products will mainly be
put on DVD/VCD/Internet/VHS. If one turns out to be that great
I'll worry about film conversion then. In the meantime I'm trying
to get the highest quality and working with what I like best,
which is frame mode for me.

As I said in the beginning expirement and see what YOU like
best.

Frame Mode Described in Detail--Not Good
 

Read this article on 24p and Frame and Interlaced Mode by Steve Mullen in "Video Systems".
http://industryclick.com/magazinearticle.asp?magazineid=127&releaseid=10439&magazinearticleid=154546&SiteID=15

After you digest this, see what you think of the dumbing down to 320 vertical lines of resolution that Frame Mode produces. My mostly positive position on the GL2 has been
taken down a bit by this.

I don't know how valid this statement is. I myself are shooting
mostly in frame mode and I think the picture lookes very nice.
Judge for yourself.

Like Rob said, who cares about numbers if it looks good. In the end that's all that matters.

True.

Four things in reply to the responses:
1. Have you read and fully understood how the Frame Mode is accomplished?
2. What looks good to some may show its deficiencies to others.
3. The lowered vertical resolution may become more noticeable if the camera tape is bumped up to a higher format in editing.
4. Rob is shooting with a PAL XM2, which has more scanning lines and more vertical resolution than the GL2.

One thing that puzzles me, is the line pair summation in interlaced scanning. This increases the strength of the image signal, but lowers the vertical resolution. Is it necessary to produce a CCD acquisition of adequate strength? Are there any models that don't use this pair summation? I wonder about the professional models with 1/2-inch and 2/3-inch CCDs.

Thus is what seperates us right brainers to the left brainers.

I can care less about a few less lines of resolution to compinsate
for the IMO "authentic" look the frame mode produces...It may however
effect very little of the image resolution when bumped up to a higher format,
yet i would rather risk the image loss than to shoot interlaced, becuase IMO
progressive or frame mode looks better than interlaced.

I agree that they should make a better CCD to compinsate for the loss
of resolution in frame mode.

That's my main point, that true progressive mode would look better than interlaced, but without the vertical resolution loss of frame mode. You can't compensate for the loss of vertical resolution in frame or interlaced modes by making a better CCD, as you'd have to increase the number of scanning lines to do so, which would make it incompatible with the video system. I wish they'd given the GL2 a true progressive set of CCDs. Maybe they will do this to the rumored "XL2" that may be floating around out there in the vaporware
zone.

The GL2/XM2 is a good and much improved model, but it's not as advanced as it could have been, which could be said for every camcorder ever made.

right....i would also like to see true 16:9 in conjunction with frame mode..
that would be nice...or maybe a camera just soley dedicated to frame mode
with 16:9 option

In the end it all comes down to performance vs cost. Maybe using a CCD that produces full progressive without the res loss would bump the camera up to a higher bracket. I like the look and for the work I do, video/DVD or web, the resolution loss isn't a big deal.

I'm afraid in the end it all boils down to what Adrian said... it's very much a matter of cost vs. performance. You want true 16:9, no problem... you just have to pay for it... the Sony DSR500 is only about $10,000 or so. I don't mean to be cynical about it, but in the long run it's all about what you're willing to pay.

Don't worry too much, with the amount of work going into CCD technology here in Japan at the moment, it shouldn't be long before we see some major improvements.

Cutting edge technology (bleeding edge?) is rarely, if ever, in prosumer cameras. If you want the latest and greatest technolgy expect to spend $50,000 and up. What we shoot with is really 6 to 8 year old technology. So, the grass is always greener on the other side of the fence, or is it? I bought an Avid Media Composer 1000 in December '94 for around $80,000 for everything. I sold it in the fall of '96 for $22,000. When I bought it I figured I had 18 months to pay for it and make my profit. It was a gamble, but it worked. I moved my company to a new level with that technology. I made my profit and more. The risk paid off. That old Avid of mine is still used by the company that bought it. It still does exactly what I bought it for, broadcast quality NLE digital editing. It's no longer state of the art by any means, that only lasted for several months. But it has made a ton of money for the guy that owns it. If you want the latest and greatest technology be prepared to spend serious cash and be prepared to do it every year or so. If you don't, your cutting edge clients will leave in a heart beat.

Jeff

Doesn't the new Panasonic ag-dvx100 have true progressive CCD's? This camera is only marginally more than an xl1s. Maybe I'm wrong here.

Cheers
Aaron

The new Panasonic NTSC AG-DVX100 has true progressive scanning at 24p and
30p, as well as standard interlaced.
It may fill the bill for many people who are looking for a progressive capability with a street price of about $3,500. However, it has a non-removable lens with only a 10X
zoom. That's enough lens power for some, but not even close for me.

However, Century Precision Optics makes a 75mm telextender that can be adapted to its 72mm barrel, that brings it up to 16X, for a list cost of $895.

They also make a 2X telextender, price unknown, for the front-end of detachable pro lenses. I don't know if its mount would fit on a threaded lens barrel, such as the DVX100 has. Century claims you can use the 1.6X and the 2X together, for what would total 32X, if feasible on this model. This combination would likely vignette in the lower half of the zoom range.

I know of no other highgrade telextenders of that large barrel size, that wouldn't be even more expensive. If someone knows of a good one that's cheaper, I'd like to hear about it. I expect the Century lenses would be high quality and I could also adapt them for use on the 77mm lens of my Beta camcorder and on my Canon L-1. The 1.6X model is actually a featured item for the Canon XL1 standard lens (for its front end, different from the 1.6X telextender by Canon for the back end---with both, the XL1 would have
almost 41X).

Got Canon GL2- Frame mode issue maybe!
 

I am going to keep this short since I am in the middle of work. But I acquired the GL2 yesterday. I mainly got it for the Frame Mode. I have had 3 XL1's (which Chris Hurd owns now) 2 GL1's, VX1000, two VX2000's and a PD150. And that's not counting the High end Cameras. As for the frame mode I know this mode better then my right foot. So after looking at tests from two GL2 cams I have noticed a more pronounced aliasing in the image in Frame Move Mode. I pulled up footage from GL1's and XL1's that don't show it like the GL2 does. This worries me, since the GL2 uses new ccd's and maybe Canon screwed up the Frame mode algorithm.

Now don't discount my ability to see issues. I found the line problem on the XL1 and had to prove it to canons best when they couldn't even see it. Mr.Hurd can vouch for my thorough analyzing eyes.

I will say that the GL2 is a big step above the GL1 in cleanness and sharpness. But I felt I should make those aware about what I'm seeing with the 'Frame Movie Mode." I plan to do more research in the next few days.

Michael Pappas
Arrival Entertainment
Arrfilms@hotmail.com

Michael wrote extensively about Frame Movie mode as early as 1997 when the XL1 was first made public.

While I was on the phone with Chris earlier he reminded me of who makes the CCD chip set in the GL2. Panasonic.........hhhmmmm

The frame mode the way it's designed should improve with better ccd's. Aliasing should decrease because of the extra resolution, not increase. The 410.000 pixel ccd plus pixel shift in two directions makes this ccd in theory like a 680,000 pixel count ccd on the GL2. That's a lot of pixel data to extract a full frame for Frame Movie Mode.

Insert Conspiracy here:

Could Panasonic deliberately hinder the frame mode feature that is designed in their chip set they OEM to Canon so it does not conflict with their 30p mode that is also going to be on their new 24p camera. The 30fps mode on the GL2 should look just as good to the untrained eye as the 30p mode on the upcoming Panasonic camera in the final product. They would know this too!

Or maybe they took that feature off their OEM ccd chip set and Canon was left to come up with the feature after the chip set. That would not be a good thing. Remember it was Panasonic that had the frame mode in 1996, years before the XL1 was even desinged. This was a Panasonic design spec in some of there ccd chip sets.

Then it could be an adjustment flaw Canon can fix.


More to come.....All opinions are welcome, lets all talk.


Michael Pappas
Arrival Entertainment
Arrfilms@hotmail.com

Hello Michael,
I don't really understand what you are asking. Are you wondering if others also see this excess aliasing in frame mode? It sounds more like you have already validated your eyes and declared this to be so (at least with your unit). Personally, I do not see this on my GL2 (as compared to my current XL1s and former XL1's and former GL1's footage) unless I crank the GL2's sharpness way up. Since this is a new feature of the GL2 (and thus a new variable with this model) perhaps your unit needs adjustment.

I seriously doubt that Panasonic would purposely flub the ccd blocks they sell to Canon for two reasons. First, it would cost a truck load of production and distribution overhead to segregate ccd's. Second, and perhaps most significantly, I'd bet tha Panasonic makes an order of magnitude more profit from their oem ccd business than they do from their camera line. I'd also bet that the g.m. of their oem imaging is paid *much* more in salary and in annual bonus than his counterpart in the prosumer camera pushing department. Jeopardizing profitable oem relationships to benefit transient prosumer product initiatives just ain't gonna happen.

Hello Ken! That was just a conspiracy theory and mainly food for thought (To many Alan J. Pakula and Oliver stone films probably) But anything is possible. As for the GL2. It's a good camera. It has a very sharp image and is a big step for Canon. If I want 60i the VX2000/PD150 are the first choice. But since I prefer 30p (frame mode feel) the GL2 is my first choice. The XL1S is great, but the GL2 appears to be sharper. It's not to hard to believe since the GL2 has 410.000 pixel vs 270.000 and has a new pixel shift system.

Maybe this is a problem because the GL2 is more sharper then the GL1 and XL1. So the softness or lack of pixel data masked out the aliasing on the XL1/GL1. Just theories.

As for Panasonic, they are my second favorite broadcast electronics company. Sony is my first. My first color video cam was a Panasonic in 1984 when I was a kid. Then when I was sixteen (1985 ) I got my first pro three saticon tube broadcast camera the M2 from Sony (a 20lb camera ). I have been stuck with Sony when it comes to cameras since, except for Canon and its FM . I had been trying to get companies since the late eighties to give adjustable frame rates, so when Canon had done it that was great. But now Panasonic has come a long way and if I wanted to spend $3000+ for a mini dv the new Panasonic 24p looks sweet! So I didn't want to sound negative towards Panasonic.

As to one of your questions. Was I asking for people to check there cameras. Yes. But.... I have been here before also. Chris Hurd can vouch for this. When the XL1 vertical line issue happen. No one could see it. I went from hell and back to get people to see it. Same thing with the Xl1s banding issue. Canon east and west coast couldn't even see the vertical lines on their own cameras back in January 1998. So I met with them in their offices in the West coast headquarters and showed them in person. I got thrashed on the net then because no one could see it. Then one by one some saw it. When Canon put out the official on it, then it was set in stone. I was clearded.

Now here I ask about the aliasing during frame mode because I see something that doesn't look right with the GL2's Frame Mode. With the GL1 or XL1 when you switch between Frame Mode and the normal 60i there is just a slight change in a stationary tripod shot. But with the GL2 also on a wide shot of curvy things etc, there is far more alias/jaggies coming into the image from 60i to Frame Mode switch. If a camera is on a stationary tripod shot and you switch between 60i to 30p you shouldn't see any big difference, especially aliasing increasing. Like I said this is food for thought.

Michael Pappas

Well indeed it's a phenomenon to keep our eyes out for, if only to add to the body of field knowledge on the GL2. I don't yet have a large body of check-able footage from the GL2 but what I've seen so far looks very good. I usually watch eyebrow edges and stray hair (on head shots) on slow creeps for such funkiness. What do you normally use as your landmarks, Michael?

Micheal

We had a thread going on this awhile back, where someone with a pal xm2 was seeing this. I did a lot of checking with my camera, and found almost no aliasing except in high contrast lines at near horizontal angles. My experience is that there is substantially LESS aliasing with the gl2 than either my xl1s or gl1.

One thing I have noticed though is that the default sharpness setting is set too high on the gl2. Have you tried lowering it a couple of notches? Perhaps your camera's sharpness is set even higher, and this is causing the aliasing.

Barry

Anyone know about Frame Mode vs Deinterlacing?
 

Hi all. Another question from me :)
Anyone know how deinterlacing software holds up against frame mode? Are Canon's algorithms better than the software ones out there or what? Reason I ask is that I was offered a good deal on a VX2000 and am tempted simply because of low light ability as I want to shoot dramitic movies a lot and envisage night/dim room scenes where the XM2 just might not handle it at all. The issue was with the fact that the vx2000 doesn't have frame mode of course, and so I'd have to deinterlace to get that film style strobing (@ 25fps here in PAL land). The XM2 seems to have a few more setup options than the vx2000 but maybe the vx wins out when they're the same price (almost)

Cheers
Aaron


Oh, the XM2's are finally here in the country, so believe it or not I'll be buying something soon ;)

I have been playing a lttle, and have tried TMPEG and I think it is DV movie maker or somthing, and both do OK at De-interlacing. I have tried them briefly with regular interlaced footage and a little FRAME footage. They seem to work better with the frame footage obviously since it was in progressive to begin with. TMPEG offers better controls I feel for handling how to de-interlace. Each option has pros and cons, all mostly affect how well motion will be handled and then percieved. If you want true deinterlaced footage then I would start with FRAME mode footage and go from there, the software options all have some cons that if you are willing to live with are fine, but none of them are perfect. From my little experiements if you will be doing much panning then software deinterlacing may create some jerkiness under some situations. I know many on this forum LOVE Frame mode and shoot entirely in it, but I feel native mode is a bit sharper, so if you don;t mind the slight loss of sharpness then FRAME mode os fine, also avoid fast pans as FRAME mode itself will seems jerky sometimes. But as usual, take this all with a grain as I am a relative newbie to DV. If Barry or Chris chime in on this one, they are the experts and can correct me where I am wrong.