All the pixels in a photo have certain level of brightness ranging from black to white. These values of the pixels serve as the input for the computer monitor. Due to technical limitations, CRT monitors output these values in a nonlinear way: Output = Input ^ Gamma
Author Archive
Dynamic Range Of Sensors
February 28th, 2011 
Andrei The dynamic range of any sensor used in digital cameras is defined by the largest possible signal divided by the smallest possible signal it can generate. The largest signal represents the maximum amount of light that can be converted by the sensor into a unique digital value that represents a pixel into a photo. The [...]
Compression
February 4th, 2011 Andrei There are two ways in which digital images can be compressed: lossless and lossy. Lossless Compression Lossless compression is similar to what WinZip does. For example, if you compress a document into a ZIP file and later extract and open the document, the content will be identical to the original. No information is lost in [...]
Posted in Digital Imaging 
Tags: compression, digital image, jpeg, lossless, lossy, tiff 
No Comments »Color Spaces
February 1st, 2011 Andrei A color space (or color model) is an abstract mathematical model describing the way colours can be represented as groups of numbers, typically as three or four values or color components (e.g. RGB and CMYK are color models). The Additive RGB Colors The cells inside our eyes (called cone-shaped cells) are sensitive to red, green, [...]
Posted in Digital Imaging Tags: Adobe RGB, CMYk, color spaces, digital image, LAB, RGB No Comments »Bits
January 24th, 2011 Andrei In digital computers world bits are the smallest pieces of information that can be stored. One bit of information has a value of either “0″ or “1″. This values correspond with the two states of a switch: “on” and “off”. The electronic switches used in computers are called transistors.
Artifacts – Part 2
January 10th, 2011 Andrei In this second (and last) part we will talk about Moire, Maze Artifacts, Noise and Sharpening Halos. Moire and Maze Artifacts If a scene contains areas with repetitive detail which exceeds the resolution of the camera, a wavy moire pattern can appear. Anti-alias filters reduce or eliminate moire but also reduce image sharpness. Sometimes, moire [...]
Posted in Digital Imaging Tags: artifacts, digital image, maze, moire, noise, sharpening halo No Comments »HCG Diet
January 8th, 2011 Andrei As holidays past, I think you will find these websites very useful: HCG HCG Diet HCG Diet
Artifacts – Part 1
January 5th, 2011 Andrei In digital photography artifacts refer to the undesirable modifications caused by the sensor, optics, and internal image processing algorithms of the camera. On low budget compact cameras these artifacts are more visible and easy to identify. On the other hand, top DSLR cameras will require a more careful analysis to identify these artifacts and most [...]
Posted in Digital Imaging Tags: artifacts, blooming, chromatic aberrations, digital image, jaggies, jpeg compression 4 Comments »Aliasing And Anti-Aliasing
January 2nd, 2011 Andrei All the pixels in a digital image have a square form. For this reason if you zoom in on areas where there are diagonal lines or circles, you will observe that they have a jagged appearance. This is the aliasing or steps effect. Here you can see an example:
Night Photography: Fireworks
December 14th, 2010 Andrei In this final night photography lesson we will talk about one of the most spectacular man made light effects: fireworks. Capturing some exciting fireworks images needs careful planning and, why not, a bit of luck. As fireworks are usually set off at night, this does give the chance to use long exposures without fear of [...]
