Tuesday, 30 March 2010

the naked truth

meaning naked as in uncovered ...

For ages there has been something separating digital photographers from film photographers. People don't often even know its there and those who do often don't even remember its there.

In management we talk about glass ceilings that prevent advancement, but in digital photography I'm wondering if the glass ceiling is indeed all the filters.

These are required to prevent the ugly aliasing effects which are associated with Bayer arrays or the heavier filters applied to prevent the sensors from seeing IR (which will disturb the colour as we perceive it), where they are quite sensitive, and to further limit the spectrum to Red Green or Blue as each respective sensor needs to be to assemble colour from the Bayer Array.

In my recent post about the 2010 Shootout I had some thoughts about this issue, and some of the comments I got reminded me of another digital camera of the distant past which seemed to side step many of these issues and take advantage of the technology with a different philosophy and design criteria.

That was the Kodak 760M camera.

Back in 2004 the above review of this camera made a simple statement which seems to have become lost:

Without an anti aliasing filter and no Bayer color matrix, the resolution of a 6 mega pixel monochrome camera is astonishing. In monochrome, 6 mega pixels effectively does what it takes 12-24 mega pixels with a color matrix

So forgetting for a moment any of the issues of how many more megapixels we can cram into a sensor, think for a moment about how much light is lost putting the sensors behind all those filters. Think about it, its well documented that a Wratten 25A deep red filter kills 3 stops.

In fact in that above review of the "special" Kodak camera (nothing more special than not munging up the sensor) Pete Meyers found his ISO was way way higher than he expected:
Correct exposure for my work meant not clipping the whites. I ended up in shock at watching exposure times go from 1/60 or 1/125 of a second with my Leica M6 and film, to 1/800, 1/1200 and even 1/1600 of a second for the same aperture with the DCS 760m. With a base ISO of 400 exposures times are brisk – another advantage of a digital monochrome over a color based sensor.

very interesting, thats a 3 or 4 stop increase.

So (if you ask me) the cost of colour digital is we get sensors which are 1600ISO but if you could just filter IR out and get rid of the other crap (I've got an IR filter anyway, and I'm sure Leica M8 users are familiar with using one too) we'd have black and white digital cameras which would give us jaw dropping image clarity and be equivalent to 12800 ISO all with existing technology.

Considering that Canon and Nikon are already putting out sensors which are 12,800 ... well that's 102,400 ISO imagine the stage photographer's joy of being able to use fast shutter speeds or even stop down a little to get better contrast.

The mind boggles ... so you guys in at Nikon and Canon, try to keep in mind that not everyone wants colour and munged black and white..

1 comment:

Lens Bubbles said...

I followed the Kodak 760M for a bit, and it was a fascinating camera and clearly one of its kind. Since no aliasing or color arrays are needed, and these filters are not cheap, the cost of a monochrome sensor camera would be much cheaper. I don't even mind if they put one on a Rebel body. I will buy one if it costs the same as the current Rebel.