I want to stipulate two things up front.
First, I love black and white. No, it’s more than that. I love black and white and — to be brutally honest — I feel very uncomfortable with color.
And second, I’m an not now, nor have I ever been, an engineer.
With that out of the way, I want to think a bit about the best way to get black and white images from a digital camera.
|Colonnade at Balboa Park, San Diego. Not a lot lost in this black and white conversion, as the original scene wasn’t very colorful. In any case, what I was most interested in was the composition and the tonalities.|
The idea of a black and white digital camera seems to come up fairly regularly. I remember reading a thread years ago on a Pentax forum from a photographer who thought that Pentax ought to come out with a black and white digital camera. More recently, somebody has suggested that Olympus do the same thing. Mike Johnston, a.k.a. The Online Photographer, reports this proposal, which was made on his blog’s comment board.
As much as I love black and white images, in the past, I have always thought that this idea was crazy. It just seemed crazy to me to throw away the color info. When I do a black and white conversion, I often find myself wanting to change the tonality of a blue sky or a pair of blue jeans, or darken a red bloom on a flower, or lighten green grass. Since my raw files contain info about color, I can do these things.
But Ctein, technical editor for The Online Photographer, points out something important that I never thought of:
An anti-aliased Bayer array camera discards about three quarters of the light hitting each pixel and has about 60% of the resolution of a dedicated monochrome camera. In other words, the quality of detail you’d get out of a 12-megapixel monochrome camera is comparable to what you’d see in a 30-megapixel color camera. Plus, the bigger, more efficient pixels make a real difference in how clean the tonality is and how well-rendered subtle gradations are.
That’s pretty interesting.
And yet, I’d still hate to lose that color info. Back in olden days, when we shot black and white film either because we liked it or (my primary reason) because it was cheaper than color, we’d use color filters to skew the tonalities one way or another, when we wanted to. You could still do that, with a digital camera, of course, and perhaps that’s the answer to my objection. But I’m pretty used to being able to look at the default rendering of my raw images to see what color something really is, and at the moment anyway I feel like I don’t want to lose that ability.
A better answer, I suspect, is provided by the Foveon sensor used in Sigma cameras. As it happens, Mike Johnston has commented on that, too, recently (“The Sigma DP2 Merrill and B&W“). With the Foveon sensor, every sensel captures red, green and blue. With normal non-Foveon sensors like the ones in all the cameras I have used, each individual sensel captures only one color, and a “filter” (usually with a Bayer pattern) manages to make remarkably good sense of what is really only a sample of the colors that reach the sensor. Seems to me that the Foveon sensor should be God’s gift to black and white photography.
Really wish I had about $8000 lying around, so I could buy the Leica full-frame, black and white camera. Some folks dream about fancy cars or sailboats; this is what I dream about it. Probably not going to happen. But perhaps in the next year I may be able to afford a Sigma DP2 Merrill, so I can give the Foveon sensor a try.