Big Sensor a Small Step for Cameras

Every camera manufacturer wants a bigger slice of that $42 billion digital-photography pie. So what do they do? They pile on bells and whistles. Smile recognition, anti-red-eye, blah, blah, blah.

Truly revolutionizing the field really wouldn’t be so complicated, though. All someone would have to do is stick a big sensor into a small camera, and then let the euphoria begin.

See, the camera companies would like you to believe that the megapixel count is the most important measure of a camera, but that’s just not true. Lens quality, circuitry speed, in-camera processing — lots of things are more important.

The best overall predictor of image quality, though, is the size of the sensor inside. Big sensors absorb more light, so you get better color and sharper low-light images. Small sensors pack too many light-absorbing pixels into too little space, so heat builds up, creating digital “noise” (random speckles) in your photos.


For all these years, then, there’s been an inviolable rule: If you wanted a big sensor, you got a big camera — one of those big, black, heavy single-lens reflex models. If you wanted a cute, tiny camera, you were stuck with a cute, tiny sensor, generally about one-tenth the size of an S.L.R.’s.

Clearly, what the world has been waiting for is a pocket camera with a huge sensor. But there are lots of reasons why nobody built one.

First, it would be much more expensive than a typical shirt-pocket camera.

Second, the maker of such a camera would have to start proclaiming sensor size as a critical measurement — thus contradicting all those years of preaching the importance of megapixels.

Third, the big camera makers might think twice about selling a compact camera that can take S.L.R.-like photos. What would that do to S.L.R. sales?

Finally, there’s physics. You can’t illuminate the entire surface of a Wheat Thin-size sensor with a tiny lens that’s only half an inch away.

Anyway, you can probably guess what all of this is leading up to: somebody finally did it. Sigma, an admired lens company that only recently started making cameras, has introduced the DP1: the world’s first compact camera with an S.L.R.-sized sensor inside.

It’s what’s called an APS-C size sensor, the same size as what is in pro cameras like the Canon 40D and the Nikon D300. It measures about 1 inch diagonally. (Nobody ever expresses sensor sizes in this simple, logical way — S.L.R. makers do it in millimeters, compact-cam makers use bizarre ratios like 1/1.8 inches — but they should. People, rise up!)

You would expect the DP1, therefore, to take spectacular pictures — and it does. The solidly built, black metal camera fits in your coat pocket (not, alas, shirt or pants), and yet it takes pictures whose color fidelity, clarity, detail and freedom from “noise” rivals the output of entry-level digital S.L.R.’s. The DP1 also easily delivers that special pro effect where the subject is in sharp focus, but the background is softly blurred — something most pocket consumer cams can’t manage.

Sigma would probably cite its use of the famed Foveon sensor as a reason for its photographic success. Each three-layered pixel on this sensor absorbs all three colors — red, blue and green. (Regular digicams use individual red, blue and green sensors parked side-by-side on a single layer.)

Photo nuts argue endlessly about the virtues of this arrangement, but one thing’s for sure: it makes calculating the megapixels of this camera very murky indeed. Sigma, counting three for each pixel (red/green/blue), arrives at 14.1 megapixels; counting each layered pixel as one yields 4.6 megapixels.

Here again, though, who cares? The point is that these photos have plenty of resolution for huge, grain-free prints, or liberal cropping away of unwanted background.

In any case, you may want to pause here for a moment to relish the happiness of Sigma’s achievement, because what follows is one crushing disappointment after another.

First, the camera is, as feared, very expensive: about $770 online. You could buy a very nice S.L.R. camera for that price. But hey — this one fits in a pocket, right?

Second, thanks to those serious optical challenges, this camera doesn’t zoom. At all. If you want to get closer to your subject, you get up and walk.

The lens does telescope outward when you turn it on, but it’s not zooming; it’s just getting the lens far enough away from the sensor.

Great innovation, but a so-so camera

The lack of zoom is probably a deal-killer for a lot of people, but not everyone. The 16.8mm f/4 lens (the film-camera equivalent of 28mm) gives it a wonderfully wide angle, which is ideal for landscapes, cityscapes, interior real-estate shots and so on.

Unfortunately, it’s no good for close-ups. The closest you can get to your subject and still attain focus is about a foot.

The camera is slow, too. Slow to turn on, slow to focus. Action shots? Forget it.

It’s even slow between shots; it takes two seconds to record each JPEG-format photo, and a ghastly seven seconds for each photo in the RAW format. (That’s a more flexible, data-rich format preferred by professionals. Unfortunately, popular programs like Photoshop can’t read Sigma’s RAW files; you have to use the included bare-bones RAW-editing software instead.)

Weirdly, there’s no optical (eyepiece) viewfinder. That’s a real problem, since the 2.5-inch screen washes out badly in sunshine. Of course, Sigma will happily sell you an external, clip-on viewfinder; for $140, you get a tiny glass tunnel you can peer through to frame your shots. Unfortunately, it attaches to the flash socket on top of the camera, decreasing portability and preventing you from using an external flash. It all seems absurd and unnecessary.

The screen has other issues, too. In low light, it actually switches into black-and-white. The pictures you take are still in color, but the screen is monochrome. What the heck?

There are full manual controls here — aperture and shutter priority, a dedicated manual-focus dial, and so on — but no scene modes. The DP1 can record movies, but they’re small; they fill only a quarter of your TV (320 x 240, far smaller than other pocket cams). Over and over, the company seems to be saying: “This is not a consumer camera — it’s a professional camera that happens to be small.”

But even pros would benefit from image stabilization, and the DP1 doesn’t have it. These days, every camera has stabilization — an essential anti-blur feature when the shutter has to stay open awhile, as when you’re shooting in low light.

That’s a real shame, because if it’s kept steady enough, the DP1 can take incredible, noise-free nighttime shots. There’s no autofocus lamp, alas, so focusing is slow. But without a tripod, you get one blurry shot after another.

Finally, there’s the lens cap. Not to be a nitpicker here, but come on; not only is it not built in, it doesn’t even have a little loop for tying it to the camera. And it snaps back onto the lens in only one orientation: logo upright. You’ll lose this thing in a week, guaranteed.

So kudos to Sigma. It has done what was once considered impossible: it has built a big sensor into a tiny camera.

But did it have to be such a lame camera? No zoom, no stabilizer, no focus lamp, no optical viewfinder, no live histogram; weak flash, washed-out screen, quarter-size movies, infinite shutter lag, loose lens cap. Hello, Sigma? 1998 called. It wants its camera back.

This is not to take anything away from Sigma’s astounding technical breakthrough. It is, however, a call to Sigma to hurry up with the DP2 — or to its rivals to pick up from where Sigma left off.

David Pogue is a columnist for the New York Times and contributor to CNBC. He can be emailed at: