Black and White Digital

After a conversation with K10d the other day I got to thinking...

The only reason I still shoot film (as well as digital) is because I always shoot film in B&W (or monochrome if you prefer).

I like the fact it forces me to think in tones rather than colours and prevents the "that's a crappy picture so I'll make it mono and call it art" copout.

So if someone developed a mono sensor it should be capable of far higher quality as it's not trying to capture colour information. In theory it would be easier to make but production runs would be much shorter so probably cost more.

So who would buy a 15mpx mono-only DSLR and how much would you be prepared to pay for it. For a point of reference imagine a K7 - everything stays the same except the sensor.

(Incidentally I think the odds of this happening are non-existant).

If you could afford a second body just for B/W that's okay. I couldn't, and therefore it is not on my wish-list.

To be honest, I don't really see the point. There are so many brilliant ways to convert colour to mono, and the camera can even be set to produce B/W images. There is nothing stopping you from thinking mono even if the sensor captures the image in colour.

Colour information is (roughly) only 15% of an image. So a B&W-only sensor wouldn't be significantly better...

Actually all sensors only see one thing and that's the light level so to speak.
Because it has a colour filter in front of each pixel a pixel sees the light level of a particular colour and with the help of other pixels seeing a different colour you create a coloured photo.
The only thing you've to do is remove the colour filter of the sensor and remove parts of the program that builds a coloured image and ur done.

But doesn't that mean that every pixel would be focussed on producing the mono image and not worrying about the colour?

I once read a Nikon manual for a compact bridge style camera and it said thet higher resolution was obtained when shooting at the black and white setting.

If this meant that every pixel was being processed instead of blocks of four then it's quite logical to presume this.

The demand for a black and white camera would probably be quite limited, but one that ignored the Bayer filter and processed differently when asked to might have a unique selling point.

As I said, I don't think this would ever be made.

But a camera with changeable sensors; one for very low ISOs, one for high, one for mono, one for IR. Now there's a thought...?

Ricoh have already come up with this idea, with matched lenses and sensors that are interchangeable on a basic body.

However, on test the results were distictly average. The price was also high. The same holds true of much high end (in theory) kit - the Leica isn't anything special either.

These things have to be a whole bunch better than a £500 DSLR to have any attraction at all. At the moment they are not as good.

Yes correct and the sensor would have more resolving power as well.

That's not true though since you can't remove the colour filter so you're still stuck with processing it in blocks of 4.

YOu can of course maybe say to use the red filtered pixels only to create the effect of shooting B&W through a red filter but that would mean only using 1/4th of the pixels

The theory was great. Ricoh just won't be the company to prove it.

As for the Leica, possibly the best made mechanical camera in the world and the only company who kept the promise of interchangeable digital backs for 35mm SLR's, but missed the boat with digital, and ended up in the mainstream struggle to survive.

Regards

So why can't you ignore the colour filter and just take the luminosity values of each pixel?

In any event, I can only tell you what the manufacturer claimed.

Because the colour filter is physically in front of the sensor so how do you want to ignore that, the only way to do that is by removing it.

You could simply take the brightness value of each pixel and ignore what colour it was underneath. The sensor only sees black and white anyway and interpolates what the colours should be.

John that's the problem since for example a pixel under a red filter only gets red light so it measure the brightness of the redlight... what if the light is green that wont go through the red filter.

It's like shooting with coloured filters with a B&W film, according what you just said it does not matter if you use a green, blue or red filter, they would all produce the same photo but we know that isn't true right.

So if you want to get the whole picture like shooting a B&W without any filter (maybe white balance filter) you should remove the colour filter infront of the sensor or do what's done as shooting in colour with a digital sensor by simply using the information from the pixels around the pixel in question and create an approximate pixel with the right colour and brightness value.
For B&W we could throw away the colour value but still the processing is the same.

The benefit of a colour digital image that you convert to BW in PP is that you can experiment with the "filtration", i.e., add a virtual red filter and compare that to adding a virtual yellow filter. With a BW only sensor you would end up carrying (as I do with a film camera) a stack of filters and trying to figure out what it would do to the image.

Cheers, Kris.