State of Imaging

Imaging sensors, the heart of any camera, have evolved quite a bit in recent years.

With CMOS becoming a major force, it's time to update what is powering the great video we shoot every day.

Sensor Sizes

The most interesting question is: Why does a smaller HDV or AVCHD camera with, say, a chip that is 1/6" in size, with over a million pixels packed onto it, have differences, both good and bad, versus a chip that is 2/3" in size, but is only considered standard-definition with about 320,000 pixels?

In a small, high-definition-resolution chip, the pixels are smaller and packed more closely together to fit onto the chip, leading to a lower signal-to-noise ratio than a standard-definition chip would have achieved. The result is that the bigger, standard-definition-resolution chip is more sensitive to light and has less visible noise in the image it reproduces.

Not all sensor sizes are native to the final aspect ratio they produce. The Canon XL H1 has three 1440x1080-pixel sensors, the Sony HVR-Z1 has three 960x1080-pixel native sensors and the Panasonic AG-HVX200 has three 960x540-pixel sensors, yet they are all capable of reproducing 1080i (1920x1080-pixel) video. Each camcorder is capable of doing this by a measure of multiple technologies and algorithms that include pixel shifting and pixel interpolation.

The Importance of the Lens

The lens plays an important part in how the sensor will work; specific size and resolution of the lens will help the sensor keep its image intact. The resolution of a lens refers to the quality of the lens and the ease and clarity with which light passes through it. Smaller-sized image sensors need a high-resolution lens with a wider field of view to squeeze the image onto a smaller area (the image sensor). Smaller chips also allow for smaller lenses, which are more affordable and will keep the costs of the camcorder down.