Buying guide - DIGITAL CAMERAS

How a digital camera works

The lens is one of the most important components of any camera. When a picture is taken, the shutter mechanism of that camera, which covers the lens, then opens for a flash of a second. The natural light from the environment then passes through the lens, which then focuses the light into the camera’s internal components. The light ‘captured’ thus, creates the ‘actual still picture’ in the camera. Some of the automatic adjustments implemented by a digital camera consist of controlling the amount of light entering through the aperture, changing the shutter speed when capturing images of speeding objects, calculating the distance of the object from the camera, and various other imperative adjustments that result in producing the best image for you.

Such electronic adjustments in most consumer digital cameras retain constant exposure on the imager. The imager is that component of a digital camera, responsible for the actual formation of the picture taken. Professional digital cameras such as digital SLR cameras (single lens reflex digital cameras) facilitate experienced photographers in making such adjustments manually as they deem fit for obtaining the best results.

Let us now take a peek under the hood of a digital camera and understand how it produces a photograph you desire to capture. Digital cameras work quite similarly to analog cameras, except that after the camera lens captures the light into a photograph as we have seen above, the analog waves of light in the photo are immediately converted into digital data. Some of the digital cameras function on a sensor called charge-coupled device (CCD), much like the photographic film inside an analog camera. This CCD is essentially a semiconductor device that has an array or matrix of photosensitive diodes. Just like in an analog camera where the lens focuses the incoming light onto the photographic film, with these digital cameras, the lens focuses the light on the CCD sensor. Some digital cameras use the Complementary Metal Oxide Semiconductor (CMOS) sensor, which functions like the CCD but produces much better picture quality. The light energy from the lens transfers to the diodes, and is converted into electrical energy. Each such diode generates electric charge that is directly proportional to the intensity of light that falls on the diode. Hence, bright light results in a higher electric current and low light a lesser electric current. This information of light intensity at different points on the array is then used to form a picture. Digital cameras form a color image by using a ‘beam-splitter’, which splits a single wave of light into three different color parts. Sensors on the CCD or CMOS, then detect the red, green, and blue hues of the picture. As we all know, all tones in the color spectrum are combinations of these primary colors. By using superimposition of these three color ‘readings’, an accurate color is formed where required. A similar procedure is followed for the entire range of light received, producing a complete picture displayed on the digital camera’s liquid crystal display (LCD) screen.

Such information is later passed on to an analog-to-digital converter (processing unit) that converts each analog charge signal into a digital value. Each such digital value is a combination of the binary numbers 0 and 1. Any digital photo thus resulted in is then saved in the camera’s memory, for later viewing on a television or saving on a computer.

What to look for in a digital camera

While a wide array of digital cameras are now flooding the market, getting your hands on the one that perfectly suits your requirements can be an uphill task. The choices are aplenty - Canon digital cameras, Kodak digital cameras, Nikon digital cameras or others – all of the major brands offer a huge selection in terms of style, functions or usage. Following are certain important features that we have listed for you to seek when shopping for a digital camera.

1. 1.    Resolution: When gauging the quality of a digital camera, its resolution must be at the top of your checklist, as this will determine the final quality of photographs taken. The resolution supported by a digital camera is generally calculated in megapixels (per inch). A higher resolution translates to denser pixel concentration, and thus resulting in superior image quality. Any entry-level digital camera supports a resolution of around 5 to 8 megapixels. High-end or professional photography, one should opt for a camera sporting a higher resolution.

1. 2.    Interface: All the images on the digital camera are easily viewable on a computer or a television. Most digital cameras have either a universal serial bus (USB) port connectivity or FireWire port connectivity. USB connectivity is the one to go for considering it supports faster data transfer, and is pretty simple to use. Currently, most digital cameras feature USB 2.0 compatibility, which is the fastest USB connectivity. The camera must also, preferably, have a TV-out jack and a bundled cable for instantly connecting the camera to a television for viewing the images taken or movies recorded.

1. 3.    PC compatibility: If the camera supports PC connectivity, then the photos stored inside the camera can be easily transferred to a computer or even a laptop for further editing, and also freeing the internal memory of the camera, making space for more images and videos.

1. 4.    Zoom: Without this feature, capturing quality pictures of objects that are located at a distance from you is impossible. Zooming enlarges an object on to the CD or CMOS sensor either using Optical zooming or Digital zooming. Optical zooming is preferable as the picture is enlarged by actually adjusting the main camera lens as against digital zooming, which magnifies the captured image by filling in extra pixels in between the spaces of different colors in the picture. Digital zoom compromises or rather degrade the clarity of the picture.

1. 5.    Memory card compatibility: Digital cameras nowadays feature a slot for expandable flash memory cards, which offer extra storage space along with the built-in memory. The maximum capacity of memory supported by a standard high end digital camera ranges from anywhere around 4 GB to up to 32 GB. This facilitates in clicking a large number of photos, and record videos of longer duration. Different types of memory cards available are Compact Flash (CF), Secured Digital (SD), Multimedia, Smart Media, Memory Stick, and XD, etc.

1. 6.    Battery: Lithium-ion batteries have now become the de facto standard and choice of digital camera manufacturers. Li-Ion, as they are commonly known, last longer on every recharge compared other rechargeable batteries like NiCd or NiMH batteries. The LCD screen of a digital camera gorges on precious battery juice. The bigger it is, the faster a battery gets drained. Thus, a long lasting battery is quite important when you plan to use the camera outdoors, as a power source for recharging a pair or two might not always be close by.

1. 7.    LCD screen: The LCD screen facilitates in viewing captured pictures or recorded videos. Any LCD screen must ideally measure at least 3.5 inches diagonally so as to provide an unobstructed view of images and videos. But, as explained in previous point, a LCD screen guzzles down a large amount of the battery power whenever it is displaying something. Thus, a camera with the option to turn off the LCD even when taking photos is the perfect choice. One can then click photos by viewing the object in a viewfinder that must be present in the upper region of that digital camera.

1. 8.    Image stabilization: When someone with an unsteady hand, or say standing in a moving object clicks a picture, the picture is never going to be clear or sharper. In such situations, the image stabilization feature comes in handy as it compensates for vibrations or jerks while you capture the image thus ensuring that the captured image clear even in shaky situations.

Making the right decision

As you browse through the innumerable options you will also be faced with a choice of the color that you may want your camera in. Almost all color options including the ever-popular black digital cameras or the stylishly feminine pink digital cameras are available under most camera brands. Lastly, prior to buying any digital camera, carefully scrutinize the product that you have isolated after considering the above-mentioned features. If possible, get a hands-on exposure to the zeroed-in digital camera, click pictures with it and then check the captured images for quality. Also, read reviews from existing owners to ascertain if that digital camera fulfilled their requirements or not. This will make for justifying the price that you are paying for the features supported by the digital camera of your choice.