Buying your first camera is kind of like shopping for a TV; they all look different, work different and cost a lot of money. Every manufacturer has their own technology for taking pictures, and yet, much of it is very similar, making it difficult to decide what's best. This isn't a new phenomena either; camera manufacturers have grappled with various films and formats for years, a practice that's continued in the digital world.
Today we'll be talking sensors — the brain responsible for turning all those pretty lights and colors into ones and zeroes. They can vary in size, anywhere from one to thirty millimetres, sometimes even larger, and dictate the sort of quality you should expect from your digital pictures. Everything from price to manufacturer can affect the type of sensor found in your camera or DSLR, and it's smart to know what all the jargon means.
To understand how image sensors work, you need to look back at
35mm film. There was a time when this image format was the de-facto standard for most professional and consumer photography. Ever since the introduction of digital, the goal has been to reproduce the same level of detail and quality found in traditional film through the use of digital image sensors. As a result, most modern camera sensors are described by how well they compare to 35mm images of old.
An Olympus PEN Micro Four Thirds model
, we mentioned
Micro Four Thirds cameras while talking about interchangeable lenses in Sony's new NEX cameras. This is a relatively recent invention from Olympus and Panasonic, and attempt to bring many of a DSLR's best features to the compact camera crowd. Micro Four Thirds cameras lack the same lens and mirror system as conventional SLRs, instead relying on just a sensor placed before a lens. However,
that sensor is somewhere around nine times larger than what's found in your typical point-and-shoot digital camera. The result is i
mproved image quality and ISO sensitivity that you'd usually only expect from larger, more expensive models. Yet, it's still much, much smaller than what's possible with 35mm film.
The sensors found in DSLR cameras use a larger format called
APS-C. This is the type of technology found in most of Canon and Nikon's mid-level cameras, and is the first consumer chip to approach 35mm levels of quality and size. Here, sensors are often referred to in terms of their crop-factor — in other words, the amount of an image that's missing, or cropped, when captured through an APS-C camera. Many Canons, including the 50D and 7D, have a 1.6x crop factor, while most Nikons and Sonys have a crop factor of 1.52x.
A handy diagram, showing the comparative sizes of image sensors against 35 mm.
Crop factor is why many professional photographers will opt for full-frame cameras. The term is often thrown about when referring to high-end professional cameras because they contain some of the largest sensors on the market — comparable in size to 35mm film. The result is an image that is not cropped in any way, and represents a similar experience to film cameras of old. However, the large sensor size comes at a price. Literally. Full-frame cameras are some of the most expensive on the market, with some models, like the
Canon 5D, often going for
over $3000, body only. The quality difference between a full-frame and Micro Four Thirds camera is obviously huge, and demonstrates just how much of a difference sensor sizes can make.
As a rule of thumb, the larger the sensor, the more detail and quality an image can include. Depending on the sort of pictures you'll be shooting, or the lenses you plan to use, knowing your sensors will make your next camera purchase go that much smoother.
Images via Flickr user pedrik, Olympus, Wikipedia.
