Dynamic Range DSLR – It is not as simple as it looks
Dynamic Range DSLR – In photography dynamic range is termed as ratio of minimum and maximum possible values of light intensities. Practically it is not possible to attain full dynamic range which is experienced by humans using electronic device. That means in practice you never encounter true black or true white, you only experience varied degree of light intensity of source and reflectivity from the source.
The whole idea of dynamic range becomes ore complex and has to be described with reference to capture device like camera, display device such as print or the subject. Each one has their own dynamic range. In addition to these, dynamic range for human eyes is also there. The image information translated between these devices affect the image reproduced. The idea of dynamic range is to be used for relative comparison between the scene, the camera and finally the image on screen or print.
The incident and reflected light intensities have a contribution towards dynamic range. The scenes with higher reflectivity that’s the one having black objects and strong reflections have higher dynamic range than the scene large variation in incident light. In either case the photography can go beyond the dynamic range of the camera, in case exposure is not perfect. When checking dynamic range, the accuracy in light intensity called luminance, is very important.
Though the dynamic range for any scene is simply ratio taken between lightest and darkest areas, its description become quiet complex when used to describe digital camera. Light is measured in digital camera at each pixel. The size and the measurement of content of each photosite decide the dynamic range of a digital camera. The contrast ratio for your digital camera is the maximum number of photons that a photosite can hold divided by the measurable darkest light intensity that’s one photon.
Dynamic Range DSLR – Measurement
If each photosite can hold 1000 photons then the contrast ratio in such a case is 1000:1. In DSLR cameras as the larger photosites are capable of holding more number of photons dynamic range is higher than compact cameras. There is increase in dynamic range for low speeds of ISO and camera device with lower noise measurement. The unit that’s commonly used to measure dynamic range in digital cameras is f-stop. The contrast ratio of 1024:1 is said to have a dynamic range of10 f-stops.
Greater dynamic range can be perceived by human eyes as compared to the one normally possible in digital camera. Also if your digital camera can capture a large dynamic range but the conversion precision of translating light measurement into digital values actually limits usable dynamic range. That’s the parameter which depends on the design of your digital camera.
After getting acquainted with dynamic range, its time now to discuss a bit about reflectors and fillin. How shadow reflectors and flash are used to improve the light conditions in digital photography that will be covered in next part.
Tutorial Seventeen – Proper Utilization of Reflectors – Photography Tutuorial
Tutorial Fifteen – Shooting RAW – Photography Tutorial