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B&W video. 1CCD or 3CCD?


Ernesto Martínez Bucio

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3CCD cameras will give you a much more detailed image.

While that's true to some degree, I'm not sure that it's entirely applicable if you're going to be shooting exclusively B&W.

 

A 3-CCD camcorder will give you considerably more accurate chroma information because each pixel is sampled for red, green, and blue separately, rather than being interpolated using a Bayer pattern, for example. However, in converting to B&W, you're essentially throwing most of that information out. In that sense, a 1-CCD camcorder should record sufficient luminance information for your purposes.

 

I suppose that two largest considerations you should make are:

  • Will you be shooting any color footage ever? If so, a 3-CCD camcorder will give you maximum benefit there.
  • How will you convert to grayscale - through a simple desaturation, or will you be using a channel mixer or equivalent tool to adjust color channels independently during the conversion?

If you're planning on shooting B&W only and using a simple desaturation process (i.e. discarding all chroma information), I'd venture to say that a 3-CCD camcorder will give you only marginal additional benefits, all other things being equal (but keep in mind that 3-CCD camcorders often offer additional pro-oriented features that 1-CCD camcorders do not, albeit at a higher price).

 

In other words, a 3-CCD camera will give you a more accurate picture, even after removing all chroma information, because each pixel was more accurately sampled for that chroma and will therefore retain appropriate luminance information after desaturation. But if you're not planning on taking advantage of that extra luminance accuracy, I don't think it's worth the extra money for a 3-CCD camcorder.

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I'm going to respectfuly disagree with troy. It may be true that all things being equal a one chip may suffice, but lets not kid ourselves. A one chip will almost always be far cheaper than a 3 chip, just by price point comparison.

 

One chips are designed to be quick, dirty and cheap. Cheap chip, cheap DSP, cheap lens, Cheap recording section. Most 3chips attempt to produce a usable video signal. Better lens, better chips, better DSP, better lens. The only exception I would put on this is perhaps the new HDV cameras that have only one HD CMOS chip, but if we are talking about a prosumer 3chip v 1chip sub-prosumer, the choice is obvious.

 

The simple rule: choose the camera that looks sharpest and least contrasty in color. If its low contrast, it probably has a good dynamic range (or a knee adjustment to fake it), and if its sharp in color, it will be sharp in black and white. Make selection based gut reaction to the cameras capabilities and you'll be set. making a selection on numbers and feature charts is terrible way to choose any camera for any end.

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Just a thought... Even though each pixel will only serve by its luminance, not is chroma, you still have three ones instead of one... And luminance accuracy, for a b/W movie, should then be considered as resolution, am I wrong ?

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  • 2 weeks later...
Just a thought... Even though each pixel will only serve by its luminance, not is chroma, you still have three ones instead of one... And luminance accuracy, for a b/W movie, should then be considered as resolution, am I wrong ?

 

I'm not sure I understand what you are saying. In DV cameras the colour is subsampled so only one channel (I think it is green) is at full resolution.

 

love

 

Freya

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The green channel is the highest res. in a demosaiced 1CCD camera, but in a 3CCD camera any one of the channels should make a decent luma source, and in combination they should provide a very good luma signal.

 

However in reality, B&W video is usually obtained by desaturating the video signal after the fact. If it is done in-camera, it would presumably happen at the chroma-subsampling stage where instead of generating a full Y'CbCr signal from the RGB info., it would sample for luminance only.

If it is done in post I assume a similar thing would happen, where the NLE simply discards most of the Y'CbCr signal..

 

Thus, the question of what happens to the RGB signal before subsampling is important in deciding which will give the best B&W picture. 1CCD cameras and any 3CCD cameras which use pixelshifting would tend to get softened by demosaicing. And since the sharpening done in-camera is usually after the subsampling (which yields the all-important Y'CbCr signal), it would be logical to assume that a good 3CCD camera will yield a better B&W image than a similar 1CCD camera.

 

This is of course presuming that we are talking about off the shelf SD cameras here, without any sort of Reeltime Andromeda type conversion...

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3CCD hands down. I have shot 4 B&W Videos, 2 of them with a one chip and 2 with 3ccd. The 1ccd camera had a good 1/3 inch chip, and the 3ccd had 3x1/4 inch ccds. The quality was hugely different between 1ccd and 3ccd. I had so many more grays with the 3ccd, the whole grayscale was so much easier to work with and had so much less de-interlaceding artifacts with the 3ccd material. The 1ccd also clipped the whites majorly, this caused both of the 1ccd films to be higher contrast, an effect which I was flaunted in the film, but didn't really want. If you have the choice I recomend the 3CCD. More options.

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I would go with a 3CCD camera, not because of the improved color fidelity that you would obtain but not need, but because of the other IQ benefits that, generally speaking, are coming with what is an inherently more sophisticated (and more expensive) videographic instrument. It isn't just two other CCDs that most 1chip cameras are lacking in comparison. What the other fellow said: the lens, DSP, dynamic range, etc.

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A three chip camera by design will give you a higher representation of resolution in black and white. Beyond that, whether its one chip or three, post production fine tuning will give you even better results.

Edited by WALTER GRAFF
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With a color recording, you have the ability in post to play with the brightness and gamma of each color signal separately and create contrast effects similar to using color filters on b&w film (darkening blue skies with a red filter, etc.)

 

Yes this is what I mean by design. With a three chip camera you can use an additive and subtractive process of contrast using the three primary colors to help accentuate contrast. Inherently a three chip camera offers you a sharper looking picture and more control of contrast either with gammas, ped, ad highlights, that affect tones by using color addition and subtraction of individual channels in grey value. But if you are asking about black and white, it might be a leap to understand all the potential in post. Start off with a three chip for acquisition and then see if you can find someone with post experience who can walk you through some simple effects using filters in post to highlight contrast and separate tones better. Perhaps I'll post a few examples of before and after and what filters I used if anyone is interested.

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