In addition to my previous post about Digital Post Porocessing, today I will write about Digital Technology in Photography - the process system that ocures inside the camera.
Digital Photography is a form of photography that uses digital technology to make images of subjects. It is one of several form of digital imaging as digital photography can be created also by non-photographic equipement (computer tomography scanners, radio telescopes or by scanning conventional (film) images). Digital sensors read the intensity of light as filtered through different color filters and convert an optical image into electrical signal. There are several main types of color image sensors, differing by the means of the color separation mechanism:
- Bayer sensor produces as many RGB pixels as photosensors through CFA interpolation or demosaicing
- Foveon X3 sensor produces uninterpolated image files with one-third as many RGB pixels as photosensors
- 3CCD produces image files using three discret image sensors with color separation done by a dichroic prism.
It is difficult to compare the resolutions based on the megapixel ratings of these types of sensors, and therefore sometimes subject of dispute. 3CCD considers the best quality and is the most expencive.
Digital memory devices store the digital image information, either as RGB color space or as raw data. The quality of a digital image is the sum of various factors, many of which are similar to film cameras. Pixel count (typically listed in megapixels, millions of pixels) is only one of the major factors, though it is the most heavily marketed.
The processing system inside the camera that turns the raw data into a color-balanced and pleasing photograph is the most critical, which is why some 4+ megapixel cameras perform better than higher-end cameras.
Therefore, image quality depends on:
- lens quality (resolution, distortion, dispertion)
- capture medium (sensor)
- capture format (pixel count, digital file type RAW/JPEG/TIFF)
- processing digital and or chemical processing of negativ and print
Images taken with digital cameras often lack on detail, depth and in dark areas often loose full details. It is best visible in image sizes from 800x600 pixels and above. To my disappointment, Canon images often lack on detail and good quality than those from Nikon, even thought Canon has put much attention to the noise reduction in its EOS series. The luck on detail remains from low up to high ISO and image looks more smeared or glazed. Nikon probably lacks on noise, but the image quality and details are much better. That noise is easy to be reduced by post-processing in Lightroom.
In my opinion Nikon D90 has the best image quality even thought it has lower ISO range than D300 or D700 or those from Canon EOS series. Surprisingly, Canon G11 has the best and the clearest image quality at ISO 100 and ISO 200. Even the background was very clear. My Sony DSC-W200 had also better images than most DSLR. D90 takes even better pictures in lower ISO than D3S or D3X. I was only disappointed by the low quality of an outdoor image. Here are other cameras better than D90. I still notice the lack on detail in the background or dark areas.
You can compare image quality with Imaging Resource Comparometer