March 09, 2009, 3:01 PM — My uncle gave me my first real camera, an old 35mm Leica with a collapsible lens. It was lightweight, compact enough to fit into a pants pocket, and took great pictures. That camera, along with many other 35mm and medium-format film cameras, is now gathering dust in a drawer, pushed aside for a larger and heavier digital SLR.
When Panasonic and Olympus announced the new Micro Four Thirds camera system last August, their promise of smaller and lighter digital SLRs had me wondering if I would finally have a camera with the compact lightweight body of that old Leica in a digital format. Micro Four Thirds and the older Four Thirds systems are very interesting concepts, not simply because of what they promise but because the basic philosophy behind the systems runs so counter to traditional thinking about cameras.
Four Thirds -- better and smaller consumer cameras
The Four Thirds system was created by Kodak and Olympus in 2002; the first Four Thirds cameras hit the market in 2003. Currently, Olympus, Leica and Panasonic all have models available, while the lenses are made by Olympus, Leica and Sigma. The system is an open standard, which means any Four Thirds camera can accommodate any Four Thirds lens, no matter the manufacturer.
The Four Thirds system (and the later Micro Four Thirds system) takes its name from two ideas: the size of a camera's image sensor and its aspect ratio. Four Thirds casts off the 3:2 aspect ratio still used by consumer-level digital SLRs in favor of a more enlargement-friendly 4:3 ratio. High-end broadcast TV cameras use an image sensor with a diagonal measurement of 2/3 of an inch. The Four Thirds systems use an image sensor that is twice the size of a standard 2/3-inch TV camera sensor. Nothing about the Four Thirds image sensor actually measures 1 and 1/3 inches, but the idea that two 2/3-inch sensors put together equals a 4/3 sensor fits nicely with the 4:3 aspect ratio.
However, more importantly, the Four Thirds System uses an image sensor that is smaller than the APS-C-sized sensors commonly used in consumer digital SLRs and that's significantly smaller than a full-size 35mm sensor.
The inventors of the system wanted to create a smaller, lighter camera that would be easier for casual photographers to handle, and the Four Thirds System's smaller image sensor allows them to achieve that smaller design.
Now, the technology has gone a step further with Micro Four Thirds, which was announced last August. The Micro Four Thirds system replaces the bulky mirror-and-prism mechanism that makes up an SLR's viewfinder with an electronic one, allowing for even smaller and lighter designs. The system also has a slightly different lens design, which means Micro Four Thirds cameras can accept older Four Thirds lenses by using an adapter (although the newer format's lenses will not work on older cameras).
So far, one Micro Four Thirds camera has come on the market. The Panasonic Lumix DMC-G1 is quite a bit lighter than most traditional SLRs and slightly smaller as well. Bundled with a zoom lens, the DMC-G1 is debuting at a hefty $800, although some stores are now selling the camera and lens for a much more competitive $670.
Is smaller really better?
There are at least two companies that disagree with the Four Thirds "smaller is better" philosophy and are making cameras with larger than standard-size image sensors. One is Sigma, which is introducing a new point-and-shoot DP1 camera. Although most point-and-shoot cameras use image sensors that are absolutely tiny when compared to SLRs (think "balance on the end of your finger" sized). The DP1 uses a sensor roughly eight times larger than the norm.
The second, interestingly, is Leica, whose soon-to-be-released S2 SLR camera will sport a sensor more than three and a half times larger than a standard SLR APS-C sensor -- or six times larger than Leica's own Four Thirds sensor.
Why, when smaller sounds so attractive, would some companies and photographers be opting for bigger? Two reasons: noise and depth of field.
Much like a smaller negative will result in grainier pictures, smaller image sensors can result in noisier pictures. Smaller sensors mean each pixel has less area to gather light and that results in more image noise (unwanted variations in brightness and/or color) in the picture.
Depth of field describes how much of the image in front of and behind the subject is in focus. Imagine you are photographing someone standing in your living room. In one photo, the person is sharply in focus, as is the entire room. You can see everything in the foreground and the background clearly. In the second image, the person is in sharp focus, but the background and foreground are completely blurred. The first image exhibits a large depth of field while the second portrait demonstrates a short depth of field.
Depth of field is closely related to the length of the lens. The size of a camera's sensor will determine how long a lens you need to get the angle of view you want. All other variables being equal, a shorter lens will have more depth of field than a longer focal length lens -- and many photographers actually want less depth of field in order to draw attention to specific areas in a photo. As manufacturers move to smaller sensors, that professional short depth-of-field look becomes harder to achieve.
Of course, depth of field is not the "end all, be all" of photography. If it were, all photographers would all use large format or medium format and 35mm would have gone the way of the dodo. Still, it is worth pointing out that there are a few relatively expensive digital SLRs on the market that use larger full-frame 35mm sensors rather than the smaller but more typical APS-C-sized sensors. It is these cameras -- for their depth-of-field facilities among other things -- that most of the pros I know lust after.
Meanwhile, for consumers and photography enthusiasts who want lighter, more compact digital SLRs, the first Micro Four Thirds cameras are starting to appear. The Panasonic Lumix DMC-G1 is certainly smaller and lighter than the competition, and the media reception has been positive; the release price of $800 was rather high compared to the alternatives, but has slipped down to a street price of around $500. A video-capable version, the Lumix DMC-GH1, is due out sometime this year.
A much brighter star on the Micro Four Thirds horizon is Olympus, which has been showing around a very buzzworthy prototype. It appears to be similar in size and shape to my old Leica, and if that is the case, it would certainly mark a significant change in digital SLR design.
Olympus says that camera will hit the market this summer, and if the size and weight are what the prototype suggests and the price is competitive, then even I might be convinced that smaller is the way to go.
