Choosing a Digital SLR

Digital single lens reflex (DSLR) cameras offer the ultimate in performance, they're fast, versatile and have superior image quality when compared to compacts. To understand why the larger sensor in a DSLR gives them a major advantage when higher sensitivity is required, visit the Digital Camera Sensors page.

The lens in a DSLR has the dual purpose of providing an image to frame the picture and to capture the actual photograph. A mirror reflects the image from the lens up into the viewfinder so the shot can be composed. When the shutter button is fired the mirror flips up, the shutter opens exposing the sensor to the light and a photograph is taken.
 

 Nikon D3
Interchangeable lenses. Every DSLR has the benefit of interchangeable lenses, this enables the photographer to fit a lens suited to the subject. For landscape photography a wide angle may be required whereas for sports photography a telephoto lens would be needed. The standard zoom lens that is supplied with the camera often has a range 18 - 55mm which in 35mm terms is 27mm (wide angle) to 83mm (moderate telephoto).  Each  manufacturer  has their own  unique lens fitting so they can only be fitted to that make of camera although third party lenses  may be available  to fit a number of different brands of DSLR.

LCD/Live View. DSLRs have LCD screens varying in size from 2.5" - 3" with a resolution around 230k. The exception to this are models from Sony and Nikon that use a high resolution 920k display. The LCD screen is used for menu selections and viewing the image after photography. Recently there have been many cameras featuring "Live View". This enables the camera user to view the image on the LCD screen before taking the photograph, as you can with a compact camera. When a DSLR has Live View the LCD is often articulated so that it can be viewed from a high or low angle.

Flash. The majority of DSLR cameras have a built in pop up flash, which isn't very strong yet is a handy source of light. They are useful for fill in flash and photography of small groups. When a high power flash is required DSLRs have a hot shoe fitting into which an external flash can be fitted. These dedicated flash units have a powerful output with the ability to zoom the flash concentrating the light on the area covered by the camera lens.The flash unit communicates with the camera to provide correct exposure, another feature is the ability to bounce the flash. 

 
                                  Pentax K20                                                        Sony A350

Image Stabilisation. These systems help minimize camera shake by compensating for camera movement by moving the sensor or elements in the lens. When it's built into the camera there's the advantage that it's available for all lenses used. When image stabilisation is built into the lens it's generally more efficient but it adds cost to every lens.

Megapixels. A basic level DSLR will have a 10 megapixels this ranges up to 21 megapixels for a professional model. Even a 10 megapixel image is capable of producing a 20" x 16" print providing a low ISO speed is used.

Sensor Cleaning. Every time the lens is changed on a DSLR there's a possibility that dust will find its way into the camera. All manufacturers build cleaning mechanisms into the DSLRs. They shake the sensor to remove any dirt. Often the low pass filter and sensor have a special coating to deter dust.

Program Modes. Basic level DSLRs are often purchased by photographers upgrading from a compact so they have familiar program modes such as portrait, landscape, sports, which advanced models do not have. With all DSLRs you have extra control with adjustments for contrast, saturation, sharpness and JPEG or RAW formats available for saving images.

Build. On a low cost DSLR the body will be made of plastic on a metal frame whereas the professional camera will have a magnesium alloy body able to take the knocks of every day use. When it comes to working parts the higher cost DSLR will have a life expectancy six times that of a basic model. This is fine for a professional photographers earning a living from their camera, for everyone else there's a wide range of DSLR cameras at affordable prices.

Disadvantages of a DSLR. The first disadvantage is the cost, for the price of a basic DSLR you can purchase two or three compact cameras. Size is another problem, no current DSLR will slip into your pocket like a compact but if you require a multi-purpose camera capable of producing high quality photographs then a DSLR is the obvious choice.

Choosing a Digital SLR. If after reading this article you are convinced that a DSLR is for you have a look at Camera Reviews on the Web page where all the cameras are reviewed. When you've decided which model you want, use the Amazon.co.uk search box below to find the best price.