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CMOS - set in stone?

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Alsone

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Hi,

I was wondering if the use of a CMOS as opposed to CCD's is set in stone.

Several potential users including myself have concerns about CMOS due to its rolling shutter causing blurring during pans and other problems during potential pro / semi pro usuage.

A good example can be seen here in this footage from a HV30 CMOS cam:

http://www.vimeo.com/865616

At 40 secs in, the strobe just whites out and blurs the picture.


Compare this to this footage shot on a lowly 3.2mp CCD stills camera in video mode (and upscaled to 720P from PAL SD!!!):

At 1 min 12 secs the strobe is absolutely perfect.

http://www.vimeo.com/882155

and its not hard to see that the current best consumer HD cmos camera on the market (that is so good its used professionally as a "b" cam" and costing £800 can't compete with a a stills camera worth all of £40 when the strobing starts and thats even after the stills video has been massively stretched!!!

Although not everyone shoots nightclubs, although many do and many nightclub scenes appear in professional movies, all film makers pan which brings in the 2nd problem of blurring during pan shots.

Is there any chance the Red team might consider giving the Scarlett a CCD arrangement instead thus taking the rolling shutter problem out of the equation?
 
We all know about these strobe/rolling shutter issues. It has been discussed here different times. When you point out the better strobe attitudes for CCD at 1:12, then - what do you mean about these typical CCD vertical smear effects every time light beam meets sensor????

Olli
 
Alsone said:
Hi,

I was wondering if the use of a CMOS as opposed to CCD's is set in stone.

Several potential users including myself have concerns about CMOS due to its rolling shutter causing blurring during pans and other problems during potential pro / semi pro usuage.

A good example can be seen here in this footage from a HV30 CMOS cam:

http://www.vimeo.com/865616

At 40 secs in, the strobe just whites out and blurs the picture.


Compare this to this footage shot on a lowly 3.2mp CCD stills camera in video mode (and upscaled to 720P from PAL SD!!!):

At 1 min 12 secs the strobe is absolutely perfect.

http://www.vimeo.com/882155

and its not hard to see that the current best consumer HD cmos camera on the market (that is so good its used professionally as a "b" cam" and costing £800 can't compete with a a stills camera worth all of £40 when the strobing starts and thats even after the stills video has been massively stretched!!!

Although not everyone shoots nightclubs, although many do and many nightclub scenes appear in professional movies, all film makers pan which brings in the 2nd problem of blurring during pan shots.

Is there any chance the Red team might consider giving the Scarlett a CCD arrangement instead thus taking the rolling shutter problem out of the equation?
Click to expand...

Don't quote me on this but I seem to remember reading somewhere on this forum that the Mysterium X sensor (which the Scarlet will have) will fix any rolling shutter problems. My brain is absolutely swimming in data so I can't say for sure this is true.
 
It seems only logical that if Red is promoting its technology and the Mysterium sensor is where its based, they are not going to deal with CCDs. Months from now we will start knowing definitely what Scarlet will or won’t have for sure, until then, it is all speculation, and we have done plenty of that already.
 
number6 said:
Don't quote me on this but I seem to remember reading somewhere on this forum that the Mysterium X sensor (which the Scarlet will have) will fix any rolling shutter problems. My brain is absolutely swimming in data so I can't say for sure this is true.
Click to expand...

Not "ANY" but a 40% improvement is expected... That is due to the fact that the combination of the new Mysterium-X sensor and new electronics are about 40% faster...
 
Peter Majtan said:
Not "ANY" but a 40% improvement is expected... That is due to the fact that the combination of the new Mysterium-X sensor and new electronics are about 40% faster...
Click to expand...

Peter, thanks for the clarification.
 
TAFKAR said:
We all know about these strobe/rolling shutter issues. It has been discussed here different times. When you point out the better strobe attitudes for CCD at 1:12, then - what do you mean about these typical CCD vertical smear effects every time light beam meets sensor????

Olli
Click to expand...

TBH Olli, I can live with smear from bright lights much better than I can live with total blur / total white out.

Peter Majtan said:
Not "ANY" but a 40% improvement is expected... That is due to the fact that the combination of the new Mysterium-X sensor and new electronics are about 40% faster...
Click to expand...

This is potentially interesting, but in truth, it needs to be a lot better than current CMOS cameras.
 
Apparently global shutter CMOS chips aren't there yet. One of the big advantages to CMOS over CCD is the variable timing the chips are capable of, which leads to multiple frame rates. I expect the other big advantages are lower cost per chip area, and individual photosite control.

In the case of the RED cameras, I've read that the cost of a global shutter would be loss of variable frame rates. The shooting possibilities with variable frame rates interest me far more than strobe artifacts and vertical shear, so I think this is a very reasonable compromise. I'm also happy to see vertical streaking disappear.

The strobe light issue is a problem you can deal with though. You just need to sync the strobes with your camera shutter, just like you need to sync your flash in still photography. While this isn't possible in every circumstance, it will be worth that extra bit of care if you want footage to turn out.

In short, strobing 'problems' on rolling shutter cameras are a result of improper lighting setup. If your production isn't concerned about proper lighting, you have no reason to expect to see proper results.
 
Correct me if i am wrong...please.

Is it also that CMOS sensors 'scan' faster and more efficiently than CCD's resulting in them being better suited for high-speed cameras. CCD'd can't offer the same dynamic range as CMOS and create more noise than CMOS. As well as chewing up more power than CMOS.

I think, ultimately, you need to understand the technology you are using and what is needed with your production and go with the 'right' choice that suits best, whether it be global shutter CCD or rolling shutter CMOS.
There are pro's and con's with both technologies and you need to decide on what suits you best for your production and if needed, go with both!

As far as Scarlet goes, remember this cam is only $3K and if you want a CCD global shutter based cam go with one of many other makes, you will be spoilt for choice! Scarlet and RED are different and offer more, and less, depending how you want to look at it.
Just my two cents worth.
 
bris-vegas said:
Is it also that CMOS sensors 'scan' faster and more efficiently than CCD's resulting in them being better suited for high-speed cameras. CCD'd can't offer the same dynamic range as CMOS and create more noise than CMOS.
Click to expand...
Not true. Even Sony (yes, those of the EX1/EX3 fame) says that if you want the highest quality/best image in a digital cinema camcorder, you want CCD. Which is why they went with CCD for the F23 and F35 and, well, everything in their lineup bigger than the EX1.

As well as chewing up more power than CMOS.
Click to expand...
That's the main thing, and the reason why Sony chose CMOS for their smaller cameras. The power requirements also dictate the heat generated, and you can't cram 1920x1080 pixels on a progressive 1/2" CCD or the resultant heat would make the camera burn up (again, paraphrasing Juan Martinez of Sony). CCD makes great images, which is why Dalsa went with CCD for their top-end camera (even though they make both CMOS and CCD sensors).

But in a small form factor, CCD can't do some things the way CMOS can. Scarlet, for example, couldn't exist as a CCD. Look at what JVC, Canon, Sony and Panasonic all had to go through to get high-def 1/3" cameras: they all had to take some sort of stance on mixing progressive scan, spatial offset, and pixel count, because you can't have it all at that small size.
Canon chose full-raster chips, but they had to be interlaced (no progressive scan possible at that pixel density).

JVC chose progressive scan and full-raster pixel density, but that just wasn't possible to do with one chip so they had to invent their "dual high speed readout" (which some people say is just two different 720x640 CCDs butted up together) and that led to the split-screen effect.

Panasonic chose progressive scan and full frame rate, and that meant lower pixel density (hence pixel shift).

Sony went with a combination of higher density but also interlaced and also pixel shift, so the FX1/Z1U has interlaced pixel-shift chips.

All four manufacturers tried something different, and they all had to make compromises.

The only way for Red to do what they wanted was to make it CMOS. CMOS = progressive scan and high pixel density, because it's low power and low heat. But CMOS = rolling shutter.

There is no perfect world. You have to pick and choose and make your compromises, and there will be compromises to be made.
 
It's my understanding that with a global shutter, the high framerates that Scarlet plans to deliver would be impossible. Also, as far as I know, designing a global shutter for CMOS is much more expensive and complicated than a rolling shutter.

So essentially (and someone please correct me if I'm wrong), the camera would lose functionality and the price would get jacked up significantly. Now, for some people, the lack of rolling shutter artifacts might actually be worth it (i.e. if you're shooting concerts, lighting your entire movie by strobe, etc), but I'm guessing the vast majority of people won't care, or even notice, in 98% of shooting situations.

It's all about the trade off, and I think in this case, it's probably well worth it.
 
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