CMOS vs. CCD?

[Yodaman]

Hey all,

I'm just wondering about CMOS sensors versus CCDs. A lot of cameras use CMOS sensors instead of three individual CCDs. I can understand that this may cut down on cost for the camera manufacturer, but there are certain disadvantages to CMOS sensors that are pretty annoying. For example, flashbanding or the "jello effect" (rolling shutter). CCDs don't have issues like this because they capture the whole image at once, whereas a CMOS sensor scans the image pixel-by-pixel, line-by-line.

My question is this; why are CMOS sensors so much more popular than CCDs when they are quite obviously not the best sensor to put in a camera? People (indie filmmakers or videographers in general) don't want to deal with flashbanding and rolling shutter. I understand that even the RED One has a CMOS sensor and thus has all of the issues associated with them (but they can afford the tools required to fix them).

Is there a big enough advantage to CMOS sensors that make them better than CCDs? Or is it just cheaper for the camera manufacturer to use a single CMOS sensor instead of paying for three individual CCDs?

Just curious on the technical aspects of this.

 

[sonnyboo]

The current trend, especially for FILMMAKERS, is the progressive image. CCD, Charged Coupled Device, are more adept at getting an INTERLACED image. Modifying this technology to acquire progressive images, and doing it on 3 chips, is a lot more expensive and counter intuitive. The CMOS sensors are progressive by nature.

That is why the trend is to trade some problems for a cheaper, yet more aesthetically pleasing image.

 

[Yodaman]

The current trend, especially for FILMMAKERS, is the progressive image. CCD, Charged Coupled Device, are more adept at getting an INTERLACED image. Modifying this technology to acquire progressive images, and doing it on 3 chips, is a lot more expensive and counter intuitive. The CMOS sensors are progressive by nature

That makes all the sense in the world. I didn't know that CCDs captured interlaced images and had to be modified to capture progressive images. I also now understand why videos shot with CMOS-based camcorders never look interlaced!

Thanks for responding.

 

[sonnyboo]

It started with the Sony/Panavision F900 series for George Lucas. Those were CCD chips. Then came the Panasonic VARICAM, and shortly after that the DVX100. These are all CCD chip cameras, and their prices reflected that cost.

CMOS takes a lot less power to use, so batteries last longer too. There is a very different look to CMOS. It's different, not necessarily better or worse, as that becomes opinion.

 

[Yodaman]

I definitely see the advantages of CMOS sensors.

Do you think that someday, they'll re-work CMOS sensors to remove rolling shutter and flash-banding issues? Those are the major turn-offs for many videographers, despite the fact that you can work around those issues (both while doing the initial shooting and in post-production).

Personally, I won't mind taking the extra steps to make sure the CMOS camera records the image without skew, wobble, etc.,. At this point the only thing that I don't like about CMOS sensors is the flash-banding issue, but if one has the correct tools, you can correct it in post. Just draw a mask over the affected frame and lighten/darken appropriately until it matches the rest of the frame. At least, I would think that's how the professionals deal with it...

I actually read somewhere (I think it was wikipedia, so the info could very well be incorrect) that film has some rolling shutter issues as well, or at least it did in the early days. Can anybody verify that?