Digital Cameras, sensor size

Follow FullPress on Google

Add us to your preferred sources.

In traditional analog cameras, the portion of film exposed to light can have various sizes, depending on the type of camera we are using. It ranges from the Kodak disc, which measures just 8×10 mm, to the Kodak Brownie with a size of 56×81 mm, up to the 20×25 cm films used in the backs of view cameras. Naturally, many other intermediate formats exist: the typical size of the most common SLRs, known as 35mm or Leica format, measures 24×36 mm. This is precisely the format that manufacturers refer to. In digital cameras, the sensor size varies from 40% to 100% of the 35mm format size. Low-end products have sensors with a surface area of just a few square millimeters, and only some professional devices achieve the full 24×36 format. To better understand what happens when using small sensors, imagine wanting to print a 20×30 photo starting from traditional film. To reach the desired size, we would need to enlarge our negative 8 times. In digital cameras, since the sensor is smaller, even more enlargement is needed to obtain the same print. For example, an image taken with a low-end compact camera with a 1/3.2″ sensor, that is, a size similar to the film used in old 8mm movie cameras, must be enlarged 66 times to print a 20×30 photo. While with a high-end compact, which generally has a 1/1.8″ sensor, only “just” 41.8 enlargements are necessary. With digital SLRs, the situation obviously changes because the sensor size is very close to the 24×36 standard format, so a photo taken with a Canon D must be enlarged 13.5 times, whereas with a Nikon DX, the enlargement is “only” 12.7 times.
But be careful, in our example we referred to the enlargement needed to achieve a certain print size without considering the final image quality, because it’s assumed that a 20×30 photo from an inexpensive camera can never match that of a professional camera. So why is it that often, even a high-end product produces only medium-quality photos? What does it depend on? Well, the problem is precisely the sensor size! Remember that resolution is simply obtained by multiplying the number of pixels along the two sides of the CCD/CMOS. Therefore, if our device can produce 8 megapixels but has a sensor that is too small, the pixels themselves will be small, otherwise so many wouldn’t fit in such a small space. Consequently, there will be an unexpected increase in electronic noise and a reduction in dynamic range, meaning photos of lower quality than expected. However, there is a way to solve the problem: buying a camera equipped with lenses of excellent quality. At the expense, of course, of our wallet.