Sharpen it

Last week, we discussed a few basic details about how digital cameras work. Now I will introduce you to a few more of their functions and explain how you can tweak some basic settings in your camera that will help you get more out of it, whether you just click away for fun or take your photography a bit more seriously.

Let's start where we left off last week. I mentioned that most digital cameras process the images before storing them. An exception to this is that Digital SLR cameras can store their images in their RAW format – that is without processing the image, but RAW is not so much an image format as each camera manufacturer has their own proprietary RAW format. When a camera processes an image they generally modify the image data in two ways. One is that the image is enhanced by the camera before it is stored.

As I mentioned last week, one of the key enhancements that are applied to the image inside the camera itself is 'sharpening' because images captured by digital cameras are generally 'soft' without clearly defined edges. The upside is that it improves image quality to an acceptable level if you want to use it straight off the camera. The downside is that cameras have limited processing power and therefore the quality of 'in-camera' sharpening that is applied is inferior to what can be done on a more sophisticated sharpening tool on a PC that is substantially more powerful. We shall discuss these PCbased image enhancement techniques in detail in the following weeks. Suffice to say that these in-camera enhancements are useful if you do not intend to edit your pictures later on a PC. If you do intend to enhance your digital photographs later on a PC, it is best to turn off or minimise the settings in your camera that process the image within it.

The second modification that is applied to an image inside the camera itself is compression. Almost all Compact pocket digital cameras and most Super-Zoom and DSLR cameras store their images compressed as JPEGs. JPEG is a 'lossy' compression technique, which means that some of the information in the image is lost during compression. JPEG is a very efficient image compression technique that is capable of greatly reducing the storage size of an image in memory, but it achieves a high level of performance by sacrificing some of the information that is captured. Storing images in the JPEG format will allow you to take more pictures on a given memory card. That's what most of us who want to have a record of a nice holiday, a family gathering or a reunion of old friends expect, but not if you are a professional photographer or even someone who considers photography a serious hobby.

Some Super-Zoom cameras have the option to compress a copy of every image you capture in TIFF format, which is a lossless compression technique. However, only a DSLR would have the option of storing the image in its native RAW format which encapsulates all the information that was originally captured by the camera. The extra information that these file formats retain is often useful when you want to enhance the image in numerous ways.

Adjusting the "White Balance" (WB) and setting it according to lighting conditions is one of the simplest and most fundamental techniques in digital photography, yet this is also one that is neglected most often. The WB setting is a reference point that the camera uses to adjust its colour sensitivity relative to a pure white surface. For example, in the light if a halogen lamp, a white will reflect a yellowish tinge and therefore the camera must reduce its sensitivity to yellow in order to capture the real colours of the image in front of it. You can set the WB manually in most cameras by opting to set the WB manually in the WB menu, focusing on a pure white surface (some photographers take a white piece of paper for this purpose) and selecting the "set" option. It may be tempting to let the camera decide what is best and keep most settings on "Automatic" mode. However, the following is an example of two pictures taken under a halogen light that are almost identical except for the fact that one has been taken with the WB set to 'Auto' and in the other, WB has been set manually.

Next week, we shall discuss a few more settings in digital cameras including ISO sensitivity and exposure compensation. I will also give you a few hints on how to make use of the histogram to monitor exposure levels and use it to improve the quality of your pictures. In the meantime, do write in to technopage@gmail.com with your questions and comments.