Olympus: 12 megapixels is enough

By Stephen Shankland on 06 March 2009, 12:14pm

Olympus has declared an end to the megapixel race.

"Twelve megapixels is, I think, enough for covering most applications most customers need," said Akira Watanabe, manager of Olympus Imaging's SLR planning department, in an interview at the PMA camera show. "We have no intention to compete in the megapixel wars for E-System [Olympus' line of SLR cameras]."

Instead, Olympus will focus on other characteristics, such as dynamic range, colour reproduction and a better ISO range for low-light shooting, he said.

Increasing the number of megapixels on cameras is an easy selling point for camera makers, in part because it's a simple concept for people to understand. Even though having more megapixels can enable larger prints and enlargement of subject matter through cropping, adding megapixels comes with some drawbacks.

For one, smaller pixels can mean more noisy speckles at the pixel level and can reduce the dynamic range, so brighter areas wash out and darker areas become swathes of black. Also, images take more room on memory cards, hard drives and Web servers, and cameras need more powerful image processors to handle them. Yesteryear's cameras already had plenty of pixels for making 8x10-inch prints, a size few people exceed.

Camera and sensor makers have been steadily improving digital cameras to compensate for the drawbacks, though. The space on the sensor that's devoted to electronics rather than light gathering has been reduced. Other improvements have come with the tiny microlenses that help each sensor's pixel to gather more light, and with the colour filters that determine whether a pixel records red, green or blue.

Some still need more megapixels

Olympus' view mainly relates to mainstream photographers. Studio and commercial photographers taking pictures for magazines certainly have a need for more megapixels, Watanabe said.

"We don't think 20 megapixels is necessary for everybody. If a customer wants more than 12 megapixels, he should go to the full-frame models," Watanabe said.

The sensors in Olympus' SLRs, an element of the Four Thirds camera system also used by Panasonic, are smaller than those in mainstream SLRs from market leaders Canon and Nikon, and much smaller than those in full-frame cameras. Those employ sensors the size of a frame of 35mm film, 36x24mm.

The view on 12 megapixels isn't a new one at Olympus.

"I personally believed, before starting the E-System, that 12 was enough," Watanabe said. "We interviewed many professional photographers -- people in studios -- about how many they needed in the future. Before we started, the system, we had a rough idea we'd be at a plateau at 12 megapixels. We gradually increased the pixel count [with the newer Olympus SLRs now reaching that level]."

Autofocus future

Watanabe had another bold projection: autofocus will change dramatically in SLRs.

Today's SLRs use a 'phase detect' autofocus subsystem in which some light is diverted from the viewfinder to sensors in the bottom of the camera. These sensors enable the rapid autofocus that helps make SLRs much more responsive than compact cameras, which use a 'contrast detect' method that analyses the data from the image sensor itself.

Watanabe believes image sensor-based autofocus will soon outperform phase-detect systems. That's important not just for compact cameras but also for SLRs that, today, often have an awkward problem with composing a shot using the camera's LCD: when the sensor is in use to run the display, the phase-detect autofocus subsystem can't be used. That means, currently, live view on SLRs is typically a frustratingly slow process.

"In terms of speed, phase detect is faster. But imager autofocus will soon exceed phase detect," Watanabe said.

Speed isn't the only factor. "In terms of accuracy, imager-based autofocus is much more advantageous. It directly focuses on the surface itself [the exact location where the image will eventually be recorded]," Watanabe said. "Phase detect focuses not on the real surface but on a virtual surface [the focusing subsystem reached via a moving mirror]."

Imager-based autofocus doesn't require the full use of the image sensor area, so it doesn't directly increase power-consumption concerns, he said. In Olympus's new midrange E-30 SLR, for example, autofocus uses only a few points on the sensor when autofocusing in live view mode.