Rolling Shutter CMOS Artifacts

[Joe Lawry]

wow... thats terrible..

 

[Stevet]

Good one...No where does it say the EX1 shot this..
But having said that, the EX1 partital flash exposures would of been close to that.

 

[StefW]

Just found this one. It's pretty bad and I could consider this 100% unusable.
If I hired someone and they brought me back this footage, they would be beyond fired.

http://blip.tv/file/703191?filename=Jetset-specialWhatFilmmakersReallyThinkOfTheWeb273.flv

EDIT: i'm not sure what camera this is from, i did a search and this thread came up, i didn't even know this was in the Sony EX-1 section

I'd say looking at the production, that one's probably not shot on a cameraphone...

Any video producer / camera person who wasn't embarrassed to present such a mess as acceptable output should consider a different vocation.

As an equipment vendor to the video industry in Australia and NZ since 1994, I would have to say that this Rolling Shutter issue rates as the most significant flaw I have seen in any professional video product, let alone camera, during my time in this industry (25+ years). Feel free to suggest other contenders.


So significant an issue that in conscience I will not sell a Rolling Shutter camera to my clients. Even if they were made fully aware of the technical problems and they still wanted it, I would suggest they bought it somewhere else. Why? Because when the Rolling Shutter issue is (inevtiably) resolved, ALL Rolling Shutter cameras will be worthless.

But there's an even more important reason - at least here in Australia:

Despite any effort by a vendor to alert the purchaser to the limitations of a product (not sure how a vendor would be expected to know about this issue if it wasnt for online communities...?), Australian consumer laws will expose the vendor's business to refund andpotential compensation claims by purchasers, who will eventually "notice" the weird flashes, banding, skew and wobble, and decide that the product is not fit for the purpose for which it was intended. If the camera owner doesn't come to that conclusion him/herself, he may do so shortly after his client rejects a job.

At the end of the day, Rolling Shutter CMOS technology (or at least its ill-conceived deployment in video and digital motion picture cameras) looks set to take a podium position among the greatest technology stuff ups of the 21st century... it's certainly winning the race for this decade. Hopefully it wont be around to be a contender in the next.

 

[matthew77]

At the end of the day, Rolling Shutter CMOS technology (or at least its ill-conceived deployment in video and motion picture cameras) looks set to take a podium position among the greatest technology stuff ups of the 21st century... it's certainly winning the race for this decade. Hopefully it wont be around to be a contender in the next.

You're joking, right?

Since most 35mm film cameras exhibit this tendency as well (albeit to a lesser extent), don't you think you are being a bit grave and dramatic here?

Or are Arriflexes the great technological stuffups of the 20th century?

Yes, most 35mm cameras are subject to partial exposure of flashes if the strobes are not synced properly with the shutter.

The rolling shutter sucks, but it only rears its ugly head in a small percentage of circumstances. Every camera system has its achilles heel and I don't see it as being any worse than the flaws of other systems.

And not everyone shoots unscripted footage of paparazzi flashes. Many of us use our cameras in resonably controlled circumstances where they take great pictures. Much like the controlled circumstances that are expected when shooting 35mm.

 

[Justyn]

would be nice to get confirmation on what shot that awards thing... cause that one montage of fash cuts with flash is just beyond terrible.


I think that CMOS camera limitations would be a serious detriment to shooting. I'd say that maybe 5 percent or more of what I shoot has some level of flash photography and rapid camera movement and it just can't handle that stuff. So I'd need to cover those occurances with another camera and that just doesn't seem prudent.

 

[lawriejaffa]

The Red and 35mm have not and do no exhibit the problems of a prosumer rolling shutter cam to even a vagely similar degree. So lets not make pointless justifications for it.

A good point is made, that when this is resolved it will impact the value of cmos cams quite dramatically.

All this pussyfooting about controlled circumstances to use a cam, where a minor oversight could completly ruin a job (especially an event capture) is just an unnecessary risk for me. So i can see your point of view StefW

 

[Code Rad]

I remember seeing some subway shots with a red and when the train went by it was skewed so bad it was laughable. The Red is not immune.

 

[LuckyStudio 13]

There is a clip of a music video shot with the RED ONE with Strobe light. It exhibits the same rolling shutter aftermath as the video above. And yet RED ONE cameras are used to produce top tier hollywood feature films all over the world.

You need to know your tools and then select the best one for that particular job. Saadly a lot of so called DP dont really know much beyond composition and pressing the 'rec' button.

 

[Jim Arthurs]

Hi all... okay, here's the deal. The EX1 and the RED have exactly the same characteristics in regard to rolling shutter skew. No difference. This isn't speculation. This knowledge gained by hands on testing.

And here is the section of pan that was pulled from to give you an indication of pan speed (this image was pulled from the middle of this pan)...

http://ftp.datausa.com/imageshoppe/outgoing/EX1/PAN_SPEED_red.mov

Now, as to the flash and strobe issues? Again, the same. Here's a test I did showing RED and multiple strobes going off.

http://ftp.datausa.com/imageshoppe/outgoing/SHUTTER_STUDIES/STROBE&ROLLING_SHUTTER.mov

Visually identical to EX1 footage of strobes that we've all seen. The difference being that you can physically sync a strobe to the RED, but not the EX1.

Now, on film. Film skews, but differently. Only the attack and retreat portions of the shutter have the potential for skew. The center of the exposure time doesn't skew. Here's an animation I did some time ago to show this...

http://ftp.datausa.com/imageshoppe/outgoing/SHUTTER_STUDIES/FILM_SHUTTER_SKEW_CLASSIC.mov

And film has issues with strobes that aren't synced, as pointed out earlier. However, since the shutter is some physical distance from the film plane and out of focus, the effect isn't as nasty. Here's a couple example from the movie Pitch Black showing this...

Regards,

 

[Amulet Man]

Nice work. Don't forget, though, that the Red has a much larger sensor (more lines to read out), so it's actually must faster than the EX1 per line; it just has a lot more lines to read. Interesting that they'd be functionally equivalent, though.

 

[matthew77]

And film has issues with strobes that aren't synced, as pointed out earlier. However, since the shutter is some physical distance from the film plane and out of focus, the effect isn't as nasty. Here's a couple example from the movie Pitch Black showing this...

Jim,

Thanks for the visual aids - it's important for all to know that the rolling shutter has been with us in some form a hundred years and that it's not the worst technological mistake of the 21st century.

BTW - the vidicon tube does partial exposures, too, but it's hard to see because a flash completely obliterates the image in most cases. Perhaps all analog video cameras can share the podium with the Panaflex as the worst technology of the 20th century? But I digress.

It actually is possible to sync strobes to the EX1 - I've done it. As long as you are at 59.94p, 50p, 29.97p or 25p you can use the analog or SDI out into a phase adjustable sync box and it works great.

When the firmware update allows 24p out of the SDI, you'll be able to do it at that speed as well.

 

[Jim Arthurs]

Hi Matthew, that's good to know about the sync trick and the EX1. That opens up a few possiblilites and doors I thought were closed.

The irony is that the first job I was going to do with RED was a green screen shoot with a limo pulling up and dozens of press photogs snapping away... the entire brain trust at REDUSER couldn't come up with an effective workaround (on the budget we had, in any case). In the end, I went F900 and just shelved the problems.

Next up was a shoot involving a slow 25 second pan around a utility shed on green screen that I needed to motion track absolutely perfectly with a perfect geometry replacement. Here again, without extensive testing, I didn't feel comfortable with a rolling shutter.

In the long run, these were both issues that caused me to pass on the RED. I was much more comfortable spending 6500 US on the EX1 than 20,000 + on the same set of issues, knowing that there would still be the need for expensive rentals to work around the shutter situation in either case.

The key with the rolling shutter is to test and know your limitations. Hopefully, this will be a very short lived phase of imager development and wind up as nothing more than a foot note in a few years.

 

[lawriejaffa]

How often must we hear this ridiculous comparison between traditional film cam technology and the rolling shutter issue of cmos video cams?

Its a completely meaningless piece of rhetoric to justify a crude technological regression. That its bearable with the RED is only because of the vast host of other benefits it brings to the table, and because the issues of the rolling shutter on that model will eventually be addressed.

Should the EX do that then great, but in the meantime, theres no point denying this achilles heel.

I think too many cam makers seem to be chasing impressive sounding specs at the cost of basic functionality and trusted and proven technoloogy.

 

[chagchag]

Hey Matthew, could you please link to a sync box and/or the lind of strobe one have to use for this kind of shoot? A product-page or something, so I'll know what to look for.

 

[matthew77]

This is not what I used - but it's probably the most elegant solution. Strobes would need to be compatible with the accessory output:

http://www.cinematographyelectronics.com/index_gallery.html

Needless to say, this is expensive. But rentable at most 35mm camera houses.

When I did it, I used something far more cumbersome, but it definitely worked - it was a motion control computer (not connected to a motion control system - just standalone):

http://www.kupercontrols.com/

Also expensive.

 

[matthew77]

That its bearable with the RED is only because of the vast host of other benefits it brings to the table, and because the issues of the rolling shutter on that model will eventually be addressed.

But that's my point - the EX1 also brings a "host of other benefits to the table"

One of them is price. But there are others. The HV20 has amazing benefits, too. And its rolling shutter is worse than the RED's. The Arricam has benefits, but also has a rolling shutter to some extent (as demonstrated).

Basically, all cameras fit somewhere in the market space with their costs and benefits. If their wasn't some compelling reason to buy the EX1, the HV20 or an Arricam or a cameraphone, no one would.

For those of us who don't shoot weddings or paparrazzi flashes, rolling shutter is barely a consideration - yes, it sucks, but it's nowhere near a dealbeaker.

I only bother to say any of this because of the earlier alarmist commentary by StefW. Again, I agree it the rolling shutter is a complete suck-fest, but it is hardly the "greatest technology stuffup" of the 21st century.

 

[chagchag]

This is not what I used - but it's probably the most elegant solution. Strobes would need to be compatible with the accessory output:

http://www.cinematographyelectronics.com/index_gallery.html

Needless to say, this is expensive. But rentable at most 35mm camera houses.

When I did it, I used something far more cumbersome, but it definitely worked - it was a motion control computer (not connected to a motion control system - just standalone):

http://www.kupercontrols.com/

Also expensive.

Thanks!

 

[JVR]

I agree and it's too bad that people have such extreme views about cameras, as if Camera_A is perfect, but Camera_B is total junk. Anyone who questions this goes to digital hell...

I've seen outstanding work created with the HVX-200 and I'm starting to see outstanding work created with the EX-1. Both cameras have strong points and both cameras have weak points, STILL users are able to produce great results with either camera. It's all a matter of person needs and wishes that defines which camera it best for each person.

A camera is a tool and just because someone selects a different tool from others, that does NOT make them a better or worse person than someone else.


Bob Diaz

No but it can make you a better tradsman!