IMAGE SENSORS IN A DIGITAL CAMERA

The image sensors in a digital camera

The image sensor in a digital camera replaces the film.There are two main types of sensors used in D-SLR camjeras. They are the CMOS (Complementary Metal Oxide  Semiconductor) and the CCD (Charge Coupled Device). Both sensors have their particular idiosyncrasies, and they have various characteristics that should be taken into account when purchasing. So it’s important to look at some example files and research the characteristics of the system you intend to purchase. When professional photographers are choosing and purchasing a camera system, they like to shoot some  comparison test shots with the cameras they’re considering. Where possible, emulate this practice. Check the  files in the image-editing software on your computer.Make sure both cameras are tested with all in-camera sharpening turned off to allow for a fair comparison. A camera technician at your local store can show you how to do this. Some sensor/camera combinations are particularly good for low light when using a sensor sensitivity of 400 ISO or higher, while others are fantastic in full natural light and terrible when used with a high ISO sensor sensitivity. Check the amount of “noise” or“grain” at a higher ISO. Do your research well and choose a suitable sensor for the type of photography you’re most interested in. Whereas in the era of film you would have bought your camera and decided on the type of film required at ? a later stage, now you have to make this important decision at the outset. It’s not just about the file size your intended camera is capable of. For instance, if the sensor is less sharp than the alternative camera, or the color characteristics less favorable, you could be unhappy with your choice. Some D-SLRs have in-camera sharpening to compensate for anti-aliasing filters, the main source of “unsharpness.” Initially you wouldn’t think that the physical size of the image sensor would be a factor to consider, since the quality of the file would seem to be the governing factor. However, the smallest sensors on a D-SLR are 18mm x 13.5mm, compared to the format of a traditional 35mm film camera, which is 24mm x 36mm. In this case, a 50mm lens, which on a film camera would constitute a standard lens, becomes a 100mm short telephoto. This initially may seem to be an advantage, since you won’t need long telephotos. But there is an issue with wide angles. A 15mm is an extreme wide angle with a  35mm film camera. With a small sensor, this is only a  slightly wide angle, equivalent to a 30mm lens on a 35mm film camera in some digital cameras. Some manufacturers are addressing this and are beginning to produce special lenses specifically for digital bodies, such as the extraordinary Olympus Zuiko Digital ED 7-14mm f/4.0. ?