What really matters in a digital camera

David Pogue has bought a Canon PowerShot S95 pocket camera and writes that a major feature is its large sensor.

I love the huge light sensor that's inside an SLR. It can take sharp low-light shots without the flash. It can blur the background the way professionals do.

What I've always wanted is a little camera with a big sensor. Is that so hard? Apparently, yes. The problem is covering a rectangular sensor chip with a circle of light from the lens. Bigger sensor? You need a bigger camera. Those are the simple bylaws of physics.

The S95's sensor is 0.59 inches diagonally -- 88 percent more area than most pocket cameras' sensors. What this means:

The little S95, can take amazing, sharp pictures in low light without the flash. The designers have shrewdly dropped the ludicrous quest for more megapixels -- it has 10 megapixels, just right -- in favor of something that really matters, like better photos. So many times I've used it  for pictures at night, indoors, in shadow. Cathedrals, restaurants, parties. No, the results aren't as good as an SLR's -- it still manages to blur a shot, especially in very dark situations when the subject is moving -- but they're light-years better than any other pocket camera can do.

The bottom line is that just counting megapixels won't tell you everything about a camera's performance. Here's a bit more on this, from Digicamhelp:

The size of a camera sensor will have a big impact on the quality of your pictures. The lens gathers light and directs it towards the sensor, and the sensor records the light to create the image.

All things being equal, a larger sensor will receive more light than a smaller one, and produce better images. This is especially important in low light photography.

When light levels are low, a smaller sensor will generate a higher amount of noise, which will decrease the quality of the images. This is why the best low-light setups include a camera with a large sensor (usually a DSLR) and a lens with a large aperture.


In the compact world, most sensors are equivalent in size. Sensor size for compacts is calculated by measuring the sensors diagonally. The most common sizes are 1/2.5 (0.4) and 1/2.3 (0.43) inches. Pretty small by all accounts.

Manufacturers have started including larger sensors in some of their compacts. For instance, Canon’s s90 camera has a 1/1.7 (0.58) niches sensor. This represents a total area 37% larger than most comparable models, and yields much better low light pictures. Compact cameras like the Panasonic LX5 also sport larger sensors.

Something to consider if you're in the market.

Image: Relative sizes of digital camera sensors