Thursday, May 31, 2007
Is There A Medium-Format Digital In Your Future?
When it comes to ultimate digital image quality, nothing beats medium-format cameras and digital backs. The word 'medium' might be tepid—the image quality is anything but.
Issues of size have always impacted image quality and changed the course of camera design. In the days of film, larger cameras delivered the best image quality, while smaller cameras provided portability and ease of use. Medium-format cameras have long been a popular professional choice because they strike an ideal balance between quality, portability and ease of use.
In the digital era, medium-format sensors deliver higher resolution than smaller sensors, but practical issues of portability and price typically have kept them from achieving the same ubiquity the format experienced with film. So what exactly is it that makes medium-format digital capture so different from smaller-format D-SLRs? It's the issues of sensor size, pixel size, file size and price that set medium format apart. The practicalities of physics and manufacturing translate to real-world issues for professional photographers.
Larger Pixels, Larger Sensors
There's only one way to increase the resolution of a digital camera sensor: increase the number of pixels. But there are two ways to increase the pixel count—decrease the individual pixel size so that more pixels fit on the sensor, or keep the pixel size the same and increase the size of the sensor itself. Only one of those methods isn't detrimental to image quality.
“You can have a medium-format sensor that has 39 million pixels in it, and you can have a cell phone camera that has 39 million pixels in it, but the pixel size is going to be very different,” explains Michael DeLuca, Kodak's Market Segment Manager for photography sensors. “Because the pixel size is very different, the performance of the pixel is going to be very different.
“All pixels are not created equal,” DeLuca continues. “Physics says that the larger a pixel is, the better it performs photographically in terms of collecting light and having a broad dynamic range. It's no different than why medium-format film is an advantage over 35mm film. It's a larger piece of real estate that you're capturing the same image on.”