- Counting Pixels
- Sensor sizes
- What's coming next?
- Sumi's snapshots
This chapter is from the book
This chapter is from the book
This chapter is from the book
What's coming next?
It's a safe bet that next year's cameras will have more pixels and more features at lower prices than this year's crop. The image sensor is one of the most expensive components in a digital camera. As with all semiconductor devices, they are cheaper to make in large quantities, so prices should come down as digital cameras become more popular.
So far, I've only mentioned CCD image sensors, but there's another type of sensor that's coming on strong. Complimentary Metal-Oxide Semiconductor (CMOS) image sensors are making a comeback. If the term CMOS sounds familiar, it's because you've heard it before. Much of the circuitry used to build PCs and other computer devices is made with CMOS technology. CMOS image sensors are very inexpensive to produce compared to CCD sensors. Early CMOS sensors suffered from poor light sensitivity, high noise levels, and awful image quality. They were typically used in low-cost, low-resolution applications like Web cameras, security cameras, and even toy cameras.
Advances in CMOS technology have led to the development of much higher quality CMOS image sensors. Canon's D30 digital SLR, for example, uses a CMOS image sensor that produces very high quality images with very low noise. CMOS sensors have some other advantages besides their low cost. CMOS sensors are made using the same process as microprocessors, RAM memory, and Digital Signal Processor (DSP) chips, so CMOS image sensors can contain additional circuitry directly on the sensor chip. This reduces the parts count, which decreases costs and increases reliability. CMOS sensors also use less power than their CCD counterparts, resulting in longer battery life.
At some point in the future, we'll reach a point where camera and printer technology reaches an equilibrium-a point where more pixels doesn't add more quality. Experts' opinions differ on where that point is. A high-quality 35mm film frame contains the equivalent of about 12-18 million pixels. But the vast majority of prints produced by commercial photo labs are 4 x 6''. Even a 1-megapixel camera can produce an acceptable 4 x 6'' print, and a 3-megapixel camera produces a 4 x 6'' print that is nearly indistinguishable from film.