Noise Annoys

One of the biggest improvements photographers expected from these small cameras with big sensors was improved image quality. And when it came to capturing photos in decent light—such as outdoors in bright conditions—the DP1, DP2, EP-1 and M9 (especially) all fared extremely well in our testing.

When shooting in low-light, however, it was a different story. The reason why is complicated and based more on the uniqueness of each camera system than one overriding factor.

First off, it's important to note that the image sensors in these models range significantly in size. Yes, they're all overwhelmingly larger than the sensors in compact consumer cameras—see drawings at the bottom of the sensor chart—but they're all sized differently in comparison to each other.




At the top of the heap is the Leica M9, which uses a "full-frame" CCD sensor that's approximately the size of a piece of 35mm film (36mm x 24mm). For comparison, the full-frame Canon 5D Mark II uses the same-sized sensor. Slightly further down the line is the X1, which uses an APS-C CMOS sensor (23.6 x 15.7mm) comparable in size to what's in most entry-level DSLRs.

Go further down, and you have the Sigma DP1 and DP2 which use Foveon sensors sized at 20.7 x 13.8mm. And then a little further down you have the Four Thirds/Micro Four Thirds sized sensor (17.3 x 13mm) in the EP1 and Panasonic GF1.

In theory, since each of these larger sized sensors has bigger individual pixels than regular compact cameras, they should blow them away when shooting at high ISOs in low light. Not so. All of these cameras were disappointingly noisy at ISO 800 and above. (In comparison, even entry-level digital SLRs with APS-C sized chips can capture pretty clean shots at ISO 800 and 1600.)

Though the M9 was the best of the lot, with such a huge image sensor you'd think it would not even be close. However, like many medium-format digital camera companies, Leica chose not to use an anti-aliasing (or "blur") filter over the sensor. The benefit is more detail and increased sharpness in bright light. The downside is you increase the incidence of noise in high ISO images.

The Sigma DP1 and DP2, which use a three-layered Foveon X3 sensor, rather than a more traditional Bayer patterned sensor, also does not employ an anti-aliasing filter over the sensor. The result? Great images in good light; so-so images in low light.

"There's a broader spectral sensitivity in the red, green, and blue channels in an X3 sensor than a Bayer sensor and that results in a color matrix that amplifies noise. So we don't tell people, if you want a really high ISO camera go out and buy this camera," Foveon's Guttosch said. "What the blur filter does is knock down your high frequency contrast. There's a good benefit but there's also a price to pay: more noise in lower light."

The EP-1, which has the smallest sensor of the lot we tested but is able to tamp down noise with its built-in blur filter, fared about how you might expect, pretty good in good light and pretty good in low light.

"Everybody's challenged in terms of the number of pixels you can put on a given area," said Olympus' Pelkowski. "And there's no perfect world in terms of electrical filtering technology."

Only the Beginning

In the end, the concept of putting a large imaging sensor in a small camera is still in its infancy and more good things should be on their way. (The DP1, it's important to remember, only came to market just over a year ago.)

Still conspicuously missing from the category though have been Nikon and Canon which, while they still release advanced compact cameras with smallish sensors such as Canon's G11, have focused their large sensor technology on the DSLR market. Meanwhile, those who have entered the Small Camera/Big Sensor market are already learning from past experiences.

At one point, Leica said it would never release a full-frame M-Series camera because it was worried the short back focus of rangefinder lenses would ruin sharpness in the corners of images. Now, only a short while later following the M8 with its APS-C sensor, Leica is receiving rave reviews for the M9 and its Kodak-manufactured full-frame chip.

"We were able to twist the sensor to match the lenses which were originally not made for digital," said Daniel. "You can prove a lot of things by optical design and say, in theory, that it should work. We were quite relieved when it did work in the end."