The advent of digital photography has changed the type of correlation that exists between the camera body and the lens. In traditional reflex systems, the value of a photographic kit was mainly evaluated based on the quality of the supplied optics, while the camera body played an almost marginal role, because only with excellent lenses could high-quality images be obtained. In digital, this is no longer the case.
The lens naturally continues to be the main component of a good photographic kit, and it is wise to invest at least two-thirds of your purchase budget in it because ten million pixels obtained using poor quality glass equal ten million poor quality pixels, and no software can correct the lack of quality. However, to achieve a flawless photograph, a quality camera body is also necessary. Not so much for the hundreds of functions each product offers, most of which the vast majority of us will never use, but for the quality and size of the sensor. This is where the big industrial battle is fought, right in the heart of the system.
The sensor is an electronic component that replaces the old photographic film and has a rectangular silicon structure made up of millions of photosensitive diodes, the photosites, which convert the light passing through the lens into electrons. There are three types of sensors on the market: CCD and CMOS, which are the most common, and Foveon, mounted only on Sigma and Polaroid cameras and on some special cameras like Hanvision.
CCD stands for Charge Coupled Device and is the most widespread sensor in digital cameras. CMOS, on the other hand, stands for Complementary Metal-Oxide Semiconductor; it is a cheaper sensor to produce because it is based on the same manufacturing technology as the microprocessors used in computing, and therefore can be manufactured in less specialized industrial plants. Thanks to its particular construction technology, the CMOS consumes up to 100 times less than its competitor, nevertheless, the image quality obtained with this sensor has always been considered much lower than that of the CCD. This is because each individual photosite mounted on a CMOS chip is paired with a transistor dedicated to converting the signal into digital format, which in the CCD, instead, is obtained through a component external to the sensor. This particular architecture significantly reduces the useful surface area dedicated to the photosensitive elements, resulting in a lowered capacity to capture images and the need to rely on interpolation to improve the final quality of the files. Moreover, the heavy presence of electronic circuits favors interference and thus increases background noise. However, with the application of sophisticated microlenses that amplify light rays, the problem seems to have been brilliantly resolved, so much so that today CMOS sensors are mounted on professional cameras such as the prestigious Canon Eos 1Ds Mark III and the brand new Nikon D300, products where quality absolutely cannot be lacking.
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