DSLR buying advice
DSLRs vary greatly in size and weight. On paper you might think that the smaller the better. But some people, especially those with big hands or long fingers, find small cameras difficult to hold and the controls too fiddly to access. On the other hand, small cameras are more likely to be taken along on trips than big, heavy ones. Decide whether you're a small camera or big camera person before buying.
At the lower end of the market the beginner models are light, with few buttons and an easy-to-handle frame. Although the grip position is different from the average compact, DSLRs are designed to feel natural with the right hand holding the body, and the left supporting the lens. Moving up through the DSLRs the bodies become sturdier and more resistant to weather, and at the pro end of the scale can weigh over 1kg without a lens.
DSLR Sensor Type
Even within DSLRs there are different sensor sizes, although the two most common varieties are APS-C and Full Frame. APS-C is the smaller variety found in beginner to semi-pro models, whereas the 35mm-sized full frame is used in pro models only. The increased scale vastly improves image quality and file size.
Don't obsess about the number of pixels a DSLR camera has. The more pixels are squeezed into a given space, the smaller they have to be, and this causes problems such as noise. A DSLR sensor is physically larger than that of the average compact, which means the pixels have more room to gather light and construct a well-exposed image. As a result the megapixel rating on a DSLR may be extremely similar to a compact, but the end quality far superior.
Our tests show that 6 million pixel SLRs can produce A3 prints as good as those from some 10MP models. Quality is dependent on a range of factors, of which the number of pixels is just one.
DSLR Systems and Lenses
Each DSLR manufacturer uses a different mount for attaching lenses. Canon, Pentax and Nikon utilise the same mount as their 35mm range, whereas Sony makes use of the Minolta SLR mount meaning each model produced by those manufacturers offers an amount of compatibility with older lenses. Olympus has a bespoke system that doesn't have any magnification issues which can appear on standard lenses when being used on APS-C bodies. Third-party manufacturers sch as Sigma and Tamron make lenses for multiple systems.
If you already have a 35mm SLR system it may be tempting to stick with the same brand, especially if you own several lenses. While this may be the cheapest option, new lens technology means you may get better results from the new generation of digital lenses.
DSLR Build Quality
The main difference between expensive professional SLRs and entry-level enthusiast ones is the build quality. Pro cameras are built to withstand knocks, scrapes and inclement weather, which makes them bigger and heavier.