CCD vs. CMOS

[Rudi Herbert]

Hello all,

My first post, though I've been following the forum for quite some time now. An abreviated version of my interest in RED is that I will be shooting my first feature some time next year and I am set on going digital, so I'm carefully considering my options and since I have discarded the CineAltas and Varicams, my road has inexorably led to RED.

Anyway, being a somewhat knowledgeable film and digital still shooter, I would assume that a CMOS design is easier to implement and deal with from a technical standpoint, plus cheaper to manufacture to boot. But I have to say I have been impressed with the resolution, sharpness and colorimetry of single CCD cine cameras like the Genesis and Dalsa, plus they don't have the shutter problems exibited by most CMOS cameras. So I wonder whether the decision to go with CMOS has been a practical/financial one for RED, or are there any quality advantages as well over the CCD design? My apologies if this has already been discussed before.


Rudi Herbert

[Graeme Nattress]

Lack of blooming / vertical streaking is the main advantage.

Graeme

[Robert Sanders]

Vertical streaking always looks like an "optical" problem to my eye.

[Graeme Nattress]

Vertical streaking is a CCD issue, not an optical one.

Graeme

[Cail Young]

Graeme, do the newer FIT style CCDs reduce vertical streaking?

[Rudi Herbert]

So then,

In terms of resolution, perceived sharpness and colorimetry, is it safe to assume that no one design is ahead of the other? I have shot DSLR's with both systems and find the differences to be mostly a matter of preference of a certain look or feel, but not of more or less in terms of the above mentioned factors. Interestingly, since the CMOS design is cheaper and easier to implement, any ideas why ARRI, Panavision, Dalsa and VIPER are all CCD based?

Rudi Herbert

[David Mullen ASC]

It's partly just because CCD has been used more in the past and the technology is a bit more "mature", whereas CMOS is just now achieving its full potential. The Arri D20 camera does use a CMOS sensor, by the way.

Read this:
http://www.dalsa.com/markets/ccd_vs_cmos.asp

[GlennChan]

Dalsa has an article on CCD versus CMOS (see the link David has in his post.)

In practice, I would just look at the end result.

In terms of sampling, the Red sensor looks like it delivers an alias+artifact-free picture, and kind of blurry at 4K. I believe this is the way of achieving the best 1080p performance... the resolution/sharpness should be fine after down-converting. To get sharp, alias-free 1080p images you need to oversample and capture a blurry oversampled image (essentially).

Noise-wise, the Red sensor looks really, really, really clean. Compare the Red stills to Dalsa, Viper, SI, etc.
Dalsa stills: http://www.dalsa.com/dc/4K_gallery/4K_gallery.asp

Some Viper stills: http://cineform.blogspot.com/2007/03/green-screen-challenge.html

SI:
http://www.siliconimaging.com/DigitalCinema/gallery_main.html
Funky stuff happens on black&white text... there is erroneous color, zippering artifacts. (CML bash greenscreen.)

[Rudi Herbert]

Thanks David,

The article on the DALSA site is very informative indeed. Well, I myself was nothing but impressed with the technical quality of both Apocalypto and Superman Returns, however others feel about it. There was a fire lit scene in Apocalypto at night that showed no noise or moire or artifacts, and the images were all clean and sharp, though the color "scheme" or pattina of the film in general had a copperish, bronze feel to it (perhaps an artistic choice), this was certainly, on the qualitative side, something I could happily live with. Now, if RED, as seems to be the case, can deliver equal or better quality at a fraction of the cost, then indeed this will be a revolutionary tool.

Rudi Herbert