Product Survey: Digital SLRs and Cameras with Interchangeable Lenses

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Now that today's digital SLRs can shoot video, the distinction between them and compacts is smaller than ever. Those pushing Micro Four Thirds (µ4/3) as an alternative to both have understand the changing nature of the digital camera market. Change is definitely on its way …

Franck Mée
Updated: October 19, 2009

End of the SLR?

You might have noticed that we've modified the title of this section to include Digital Cameras with Interchangeable Lenses. What's changed?

Well, SLR cameras are so named for their Single Lens Reflex technology, which use a series of mirrors and prisms to reflect a 'preview' of the image that would fall on the sensor when the photographer releases the shutter into the viewfinder. For the past few years, almost every camera with interchangeable lenses has been one of these SLRs.

Last year, however, Panasonic was the first manufacturer to unveil a camera that used the µ4/3 system. In many ways this new breed of digital camera is closer to a bridge, or even a compact, than current SLRs, but they use large sensors and have interchangeable lenses.

Although µ4/3 cameras are relatively rare for the time being, we've updated our Product Survey to take into account this new breed of camera, recognizing the potential for interchangeable lenses to allow photographers to choose a lens that suits their subject best.

It's no secret that the larger the sensor on your digital camera, the better the results. This is for two reasons. Firstly, a larger sensor can capture more light--but it also allows you more room to adjust the depth of field to focus on what you want. This could mean a portrait shot where the background remains blurry with a sharp view of the subject's face, for instance.

Sensor Size Compared:
On the left, a photo from the Fuji F100fd, one of the best compacts available but with a small sensor. On the right, the same shot taken on a Nikon D90, with a much larger sensor. In particular, note how the thin strands have hair still stand out even in the shadows.

The problem with these bigger sensors, though, is that lenses can't keep up. When you've got a sensor that measures 5.5 x 4 mm (0.2 x 0.15 in), it's perfectly reasonable to make a powerful wide angle lens with up to 10x zoom on a compact, or on a 20x zoom on a bridge.

That's just not the case when your sensor is 23 x 15 mm (0.9 x 0.6 in), and some 'multifunction' lenses are impracticably large: up to 550 g (1.2 lb) and 20 cm (8 in) long for a 12x or 15x zoom. Lenses like this represent an inevitable compromise, and often struggle in low light and when the zoom is pushed to the maximum.

The problem for camera manufacturers is finding an acceptably-sized lens that also provided enough light for ever-larger sensors.

The usual solution to this problem is to fit a system of interchangeable lenses. According to the task at hand, a professional photographer might choose to use a wide-angle for a landscape shot, a specialist portrait lens or a telephoto for nature photography. Each of these different lenses offers limited zoom (around 5x), but is specially designed to give the best quality image for a given type of photograph.

Professional Use Only?

For a long time, SLRs were effectively the only digital cameras that used interchangeable lenses. Used mainly by professionals, they were expensive and difficult to master. Little by little, though, they've gained in popularity, with Canon's EOS 300D one of the first truly affordable digital SLRs way back in 2003.

Nevertheless, digital SLRs still have something of an elitist image, and the lack of automatic assistance found on digital compacts often gave the impression that they were designed not only for budding photographers but technical experts with the time to master their complex settings. The average user who wanted great photos without needing a degree in optical physics was left to one side.

Recently though, prices have been falling, and it's increasingly possible for average users to consider a camera with interchangeable lenses. At the same time, manufacturers have made big strides in demystifying the world of SLRs, with both the Nikon D60 and the Pentax K-m enjoying streamlined interfaces targeting less advanced users

The Panasonic G1, meanwhile, the first camera to use the µ4/3 standard features all of the same automatic features as the manufacturer's most basic entry-level compacts. In particular, Intelligent Auto mode made its début on an SLR, allowing the user to line up their shot and focus, leaving the camera to choose the other settings automatically.

Now, the big challenge for the manufacturers is to keep on improving the accessibility of these cameras without producing dumbing them down so much that experts feel they're held back.

See Also

If you're looking for a bargain, one good place to start is with slightly less recent models. Try our recommendations in our Product Survey: Digital SLR Cameras 2007-8