Anyone seeing any rolling shutter issues?

[Carlos Moreira]

there is no visible rolling shutter.
look on this thread:

http://www.dvinfo.net/conf/showthread.php?t=109146

here you can see a 60p slomo, handcamera, fast movements and pans in different directions. Even when you search for RS you´ll not see anything. And this is some kind of "worst case".

I guess the panasonic users discussion shows simply some frustration. And another thing is generally how to work with a true progressive 24p camera. Because of 24p strobing and shutter there is lots of things which look bad, even with the most expensive 35mm camera. E.g. you simply can´t do pannings with lots of vertical structures in picture, this simply looks awful.

provoking issues like RS may be possible, but does it make sense ?

[Chris Leong]

Hi there

Following this post I realize that there are many issues that are a lot more subjective than I realized.

I have film and both CCD and CMOS cameras and use the one that suits the job or the shot the best. It's just a way to get an image onto a screen.

Also, while I understand that this is a mainly technical thread (and I myself am lined up for an EX1 - we have access to an HVX at work), if people watching our programs are worried about the slanting verticals on fast pans (like the arri film cameras always had) or about the 7 second pan rule, or about the tiny bit of top left vignetting, then I'd say there was something wrong with the programs they're watching, apart from technical issues.

Yes, there may well be a tech issue here that, I fully concur, involves sending back cameras if only because, at the prices we pay, we expect a product to work as well as the cheaper ones we already own. I've swipe panned a demo EX1 to death to try and get the verticals to lean like they do on my FX7 but couldn't get it to do that, at least in the viewfinder screen. And personally, in some shots, I like the lean.

Personally also, having shot with the JVC HD cameras and others, I think the crispness of the EX viewfinder is a huge thing - since the days of 60"+ viewing monitors, I've always carried a minimum 24" full HD res monitor on set so I can have someone double check focus and back focus as I'm shooting. Overkill? You haven't been bitten by that one yet. Very damned embarrassing to have a soft shot that glares out at you and everybody else -- at the large screen premiere...

(I use an inexpensive video projector at the output to my NLE these days when I'm editing HD, just to remind me about that incident...)

Finally, the 24p thing. After setting up a high end shoot with very high quality monitors and studio HD cameras, etc., I finally got to see pristine 24p 4:4:4 SDI movement on a large pro digital screen in all its studio lit glory - and to my eye it truly, sharply, high definitely, sucks.

Don't flame me, but I've been shooting film since 1975 and IMHO, nowhere, nohow does this 24p ever look like film. Here's why:

Film shot on 24fps has always been transferred to television standards when seen on the small screen. So the big name studio 35mm film productions have always been seen in interlaced video, with its 24 frame camera speed nowhere to be seen.

In the cinemas, on the big screens, a film projector has a butterfly, or a bowtie shaped shutter, flashing each frame twice. (It's only the cameras that have pie plate, (around half a pie missing) shutters that expose the negative once per frame, i.e. 24fps, or 24p.)

Thus what we watch on a cinema screen is a 48 fps image, not a 24 fps image. Never have.

Even the Steenbecks or KEMs we used to cut with that had 24 face prisms, had a blurring (frame blending) effect as the prisms shifted, so most editors (not using an upright Movieola) didn't ever see true 24p images.

So imagine my surprise when I watched the pristine SDI result of all this high end technology and thought - "what's this? This isn't film like at all. I've never seen images like this before."

Which, ultimately, is how it should be, I guess. Tech shock.
It's new technology, not just repeated (or simulated) old tech.

I'll get used to it (but of course will never shoot my own stuff at 24p without conversion downstream) I just wish they'd not marketed it as such, since I now feel that it's been misrepresented at best.

Love the depth and sharpness. Hate the fact that the only way to get decent focus is not TTL optical but still only electronic. [Don't tell me that electronics has better res. The day I try to walk through a huge HD screen because my eye can't tell the difference is the day when you're right and I'll change my mind. Yes, of course, take both techs and develop them fully and they will be the same. Eventually. We already have the optics. Film resolution is already down to the molecular level, not lines per mm or pixels per screen. It's just that everybody's way over paying Eastman or Fuji or the labs for everything any more. Those days are gone for good and I add my personal good riddance for the most part, not all, though, because I use film still for some shoots. For some shoots, film is the only medium to use. I'd hate to lose it like I'd hate not to be able to use a color in my pallette]

On a high end shoot I can carry my 35mm cameras, some film, a video tap and a monitor, done deal.
In HD there's the camera, big screen with video village, Apple cart with computer, yadda yadda.

I'm not even talking my S16mm camera against the HDV, now also with a 24" screen and a video village to go with, plus an alert assist with a sharp eye, because of abovementioned out-of-focus paranoia.

However, I hope that I'll get around to trusting the EX1 finder alone because it sure looks better than the others in its class. Having a fixed lens means less back focus hassles too. Being a film guy, back focus issues between lenses have always been something of a surprise to me, usually more to do with video taps than actual shooting lenses.

But HD sure is cool and an EX1 will eventually be mine!

[Carlos Moreira]

Hi Chris,

agree with the most things.
But the 24 / 48 thing has the simply reason to reduce the flicker on a big screen, but the feeling of motion and strobing is still 24p! Its part of abstraction and is very helpful to do fiction / storytelling.
This feeling also remains if you transfer true 24p it to interlaced standards, because two fields just show the odd and even part of the same picture / progressive frame.
Also on a 100 Hz or 60 Hz Monitor 24p looks like true 24p.
The technical quality of 24p is bad, you are right. But If you use higher framerates or interlaced on the camera this "abstract" feeling gets lost and it more looks like a typical TV / reality show.

[Piotr Wozniacki]

Originally Posted by Carlos Moreira

Also on a 100 Hz or 60 Hz Monitor 24p looks like true 24p.

Not quite. For it to look right, the refresh rate of the HDTV must be a multiple of 24; the new Pioneer Kuro line has the "24p DirectCinema" mode at 72Hz, and Toshiba Regza - 120 Hz. This gives much the same effect as the cinema screen 2x24fps (with 3x24 and 5x24 fps, respectively). The 120 Hz mode is also great for 30 and 60 fps material.

Of course the European models also have the 50Hz refresh rate for PAL compatibility (often doubled at 100 Hz to minimize flicker).

Believe me, they do make a difference!

[Chris Leong]

Carlos

Okay, so I agree with you, but something is still very wrong. Maybe it's that, since we use a revolving shutter in a cinema, what we're actually seeing is a series of vertical wipes to black and back, instead of entire images popping up and changing, with no black moments? Whatever it is, it looks decidedly unlike a movie camera shutter.

Since I do reality TV by day and indie film by night, this is certainly an area that I'm very interested in.

But the rolling shutter issue, as far as I have experimented with, is really a non-issue in practical terms. The stills camera flashes are easily fixed in post and as I've said, I kinda like the speed lean of the CMOSs in fast lateral movements.

Maybe if one were shooting lightning? Don't have experience with that.


Piotr
Thanks for that info. Looking forward to trying some of that gear out myself.

[Paul Curtis]

I don't know whether this is genuine or not

http://www.youtube.com/watch?v=A_g6cTLzjmc

Now obviously this was being looked for, it's seems a little too much which is why i wonder whether it is an EX afterall. He does state the shutter was at 180 at 24p and therefore this slow shutter speed could well yield this type of result. Would anyone like to confirm it with theirs, it seems blindingly obvious to find (if it is true!)

cheers
paul

[Graeme Fullick]

Paul,

I watched this clip!
You know I must be wierd, but I don't shoot like this!

Should I now panic and cancel my order? Or just order a different camera with low res CCD's so I can make people sea sick by throwing the camera around.

[Gwynne Williams]

I'm not quite sure what this clip should prove except it would be an unwatchable clip on whatever camera it's shot on. Taking this further, you could even open the iris fully, then up the gain and prove how the highlights are blown away I suppose.lol.

[Paul Curtis]

Don't shoot the messenger!

I posted it here to see if anyone here can replicate it. Whilst this is obviously an unrealistic and extreme result i think most people would like to know whether there is less extreme but more common effect here somewhere, even if it's just the partial exposure issue. I think there is a still image in one of the threads here with a slanted fence as an example. And yes there's a thread about the nature of the A/D convertors on each column, and it's been used in 10G planes etc,. etc,.

It does have a rolling shutter so at some point it will exhibit these artifacts, it's really a question of at what point and whether there are situations it will prove problematic. That's an issue of what you need to do with the footage

My concern is more to do with the wobble effect and it doesn't have to wobble much to make vfx tracking very difficult (i have a project in the new year that i will need to do a lot of this). Over a 1920 frame even a subtle wobble will make a difference. So i personally keep an eye out for any results that make my life harder :)

I have no alligence to any cameras, i have a Z1 which i don't like much and will probably grab an EX in the new year as it seems to be what i was hoping the Z1 was. Or maybe a red once the dust and hype settles (and you can actually buy one)

cheers
paul

[Bob Grant]

I guess that clip proves the EX1 handles high G forces.

[Drew Long]

Originally Posted by Steve Mullen

I say "perceived" because most folks shooting with the V1 have no real world problems with rolling shutter. But, some may. I suspect that XMOR technology reduces the chance to near zero.

Steve,
Unfortunately when the 3ClearVid CMOS sensor's rolling shutter effect does rear its ugly head, it's pretty devastating. I don't have my clip now but 2 frames are affected by strobes going off. Pixellation in the first frame (must be the compressor getting fried by the strobe's) and also partial exposure, then the second frame also has partial exposure.
It's a split second but it is noticeable.
I am also interested to see if the EX1 is able to evolve past this shortcoming of the CMOS sensor.
That youtube clip proves that the wobbles exist, but only for those who shoot motorX from the bike's perspective. I think the problem of partial exposure of the frame is the bigger issue for those shooting in scenes with big flashes of light. I wonder if lightning can get it to do the same thing.

[Steve Mullen]

Originally Posted by Drew Long

I don't have my clip now but 2 frames are affected by strobes going off. Pixellation in the first frame (must be the compressor getting fried by the strobe's) and also partial exposure, then the second frame also has partial exposure.

I'm not sure flashes reveal rolling shutter. Rolling shutter is a very specific warp to an image. Flashes destroy compression even on CCD cameras -- just watch a red carpet show.

The fact is that every imaging and recording system can be provoked in misbehaving. If I flung cameras around I guess I might be concerned about issues X and Y. But, I don't. I worry about low-light sensitivity and vertical smear -- open air night markets in Asia interest me. So when the V1 works fine except I a need a couple more stops of sensitivity -- I can be fairly sure the EX1 or Z7 will work FOR ME.

I'm far more interested in technology that provides overall performance improvements. I'm less interested in worrying about some defect that might be provoked in some low probability situation. Those interested in dissing a new technology will be looking for, and posting about, the low probability situation to take our eyes off the huge overall improvement.

[Steven Thomas]

The utube video is bogus...
I have tried this test the day I received it, and also last night after looking at the joke video. It was posted by someone who does not own the EX1 and stated he tested it. Does the EX1 has some of these artifacts, I'm sure it does, but I have not seen any on mine.
hmmmmm

[Paul Curtis]

Originally Posted by Steve Mullen

I'm not sure flashes reveal rolling shutter. Rolling shutter is a very specific warp to an image. Flashes destroy compression even on CCD cameras -- just watch a red carpet show.

There are plenty of examples where they do. If a high speed flash goes off whilst the camera is reading out the cmos frame then half of the frame would get a different exposure.

It is also true that flashes affect compression badly, but there is a specific artifact with cmos rolling shutters to look for

For that reason you'd probably not get any ENG types waving cmos based camcorders at red carpet events :)

paul

[Greg Boston]

Originally Posted by Steven Thomas

The utube video is bogus...
I have tried this test the day I received it, and also last night after looking at the joke video. It was posted by someone who does not own the EX1 and stated he tested it.
hmmmmm

Steven, I'm quite certain that Chris would be okay with hosting a video clip that replicates the settings of the Youtube video (24p, 180 degree shutter). Shake the camera in a similar manner with, and without image stabilization on. Sorry, but I consider the original source to be very suspect.

-gb-