DSLRs: What to look for today (Feature)
By Jay Dougherty Mar 9, 2009, 2:08 GMT
Washington - Digital cameras that accept different lenses - referred to as DSLRs - won't exactly take your pictures for you. But these days, they come close.
The features war has been raging among manufacturers of these sought-after cameras, and the result, for consumers, is a dizzying number of choices and specifications.
DSLRs today are not only less expensive than similar models of just a year ago, but they also offer more - far more. The challenge for shoppers, though, is to know which features matter. Here's a rundown of what to look for.
--- Anti-dust technology
There's always been one big problem with using DSLRs: dust. The first few generations of DSLRs allowed dust to get inside the camera and onto the camera's sensitive imaging chip - generally referred to as the sensor - during lens changes. The result was stubborn blotches on photographs and dirty sensors that were close to impossible to get clean. Many manufacturers, in fact, made the situation worse by requiring that owners send in their DSLR on a periodic basis if they wanted the sensor cleaned - a routine that was both time-consuming and costly.
The good news is that many manufacturers of DSLRs - although not all - now offer some type of anti-dust technology. Often this feature works by gently shaking the filter that sits in front of the camera's sensor each time you turn the unit on. When this works properly, the shaking causes the microscopic dust particles to fly off of the sensor and onto some sticky substance surrounding the sensor. There the dust stays.
Many DSLR owners find that the anti-dust technology works reasonably well, but it's not foolproof and it will not necessarily mean that you'll never have to get your camera professionally cleaned. But it's better than nothing - and you should look for the feature on any DSLR you buy today.
--- Anti-vibration technology
Another contributor to poor images is camera shake, which is what happens when you're shooting in low light, without flash, and you can't hold your camera still long enough for the camera to take a sharp picture. The result: blurriness in your images.
Canon was one of the first camera makers to combat camera shake with image stabilisation (IS) technology built into some of the company's lenses. Nikon eventually followed suite with its own vibration reduction (VR) lenses, and other DSLR companies, such as Olympus, bring image stabilisation technology into the camera body itself, meaning that it's not lens-dependent.
Whatever the system used, image stabilisation is a feature you shouldn't be without, for with it, you can get sharp images in low light situations that before would have resulted in worthless pictures.
--- Live View
Many compact digital cameras have done away with the traditional viewfinder as a way to frame your images. Instead, they use the LCD on the back of the camera to allow you to view and frame the image in real time. DSLR makers, by contrast, have not been able to offer image framing on the LCD, since the 'through the lens' technology on which DSLRs are based has not allowed live framing.
That, however, has changed. Many recent DSLRs offer you the ability to frame photographs both by using the traditional viewfinder and, when desired, by using the LCD in what is referred to as a 'live view' of the scene.
Using the LCD to see and frame your image has its advantages. With your eye away from the camera, you have more versatility in where you hold the camera, and you can even use the LCD's ability to zoom in on a scene to make precise focusing adjustments. In short, the live view feature is a boon to DSLRs, and you should look for a camera that offers it.
--- Lenses optimised for digital
The original DSLRs were designed to fit the 35mm lenses in the manufacturers' stable. Canon, Nikon, and Olympus, for instance, have their roots in the world of film, and these camera makers had a wide range of lenses available for film cameras. It made great sense, therefore, to offer DSLRs that would work with those lenses, since owners of these systems often had lots of money invested in them.
35mm lenses, however, were obviously designed and optimised for a different type of light-gathering device, and it's quite possible, and often preferable, to create a new lens system that is optimised for working with the digital sensors found in DSLRs.
Canon and Nikon, among other manufacturers, recognised this, and these companies are slowly bringing out digital-only lenses. Nikon calls these DX lenses, while for Canon they carry the moniker EF-S. These lenses are typically smaller and often lighter than the equivalent focal length lens designed for 35mm cameras, and they can also be sharper.
The downside, though, is that they won't work on older film =cameras, and they often won't work even on certain older-generation DSLRs from the same manufacturer or on more expensive DSLRs in the current model lineup. But buying a DSLR that accepts the new- generation lenses as well as the old can make good sense if you're focused on the future. Your kit will be lighter, and you'll be getting lenses that are optically optimised to work with the digital imaging chip at the heart of all DSLRs.
--- Low noise / high ISO
The holy grail of today's advanced DSLRs is low noise - or the ability to take images that are relatively free of digital 'grain' when shooting in low light. One of the biggest advances of recent- vintage DSLRs is their ability to minimise digital noise - which often shows up as multi-coloured pixellation, robbing an image of detail - even under very poor lighting conditions.
As DSLRs get better at controlling noise, they give you more latitude in increasing the ISO value, which is a measurement of how light sensitive a sensor becomes. The higher the ISO value, the less light you need to get a shake-free image. Some of the best of today's DSLRs offers ISO values that were unheard of in the days of film - as high as 64,000 in some cases. With an ISO value that high, you can achieve fairly fast shutter speeds - and therefore shake-free images - in a dimly-lit room. Look for DSLRs, therefore, that offer high ISO levels.
--- Bottom line
You'll notice that there's been nary a word here about the specification that gets the most headlines: megapixels. That's because the number of megapixels a contemporary DSLR camera offers has less to do with final image quality than the other features mentioned here. Most DSLRs have a sufficiently high megapixel count to provide sharp images at sizes that most people won't even print. So buying a DSLR based on megapixels alone is probably a mistake. Pay attention to the features that let you get the best image in the conditions under which most people shoot, and you'll come out ahead.