PHOTOGRAPHY BLOG

If your camera can shoot in RAW, you should shoot in RAW because Adobe’s RAW processing engine has dozens of powerful tools for fine tuning your digital images. I’ll try and show you how to remove Chromatic Aberrations using Adobe Camera RAW processor.

But first, what are Chromatic Aberrations?

CA or Chromatic Aberration is a purplish, bluish or greenish fringeing around the edges of Digital pictures caused by poor lens design, or good lenses used under certain lighting conditions. Teleconverters or Extenders are notorious for inducing CA. So are low cost P&S Digital Cameras. You can see this purplish fringeing at the edge of Pharaoh Ramses’s face in the illustration below, which is a crop from a NEF (Nikon RAW) file. In the diagram, I have tried to illustrate how Chromatic Aberrations are caused by poor quality, or poorly designed lens systems. The good lenses are expensive because they incorporate several lens elements and exotic coatings to reduce or remove Chromatic Aberrations ….. Full Article.

Infrared (IR) radiation falls into the light spectrum beyond red and is invisible to human eyes. However, some digital cameras can clearly see the light in the near-IR spectral range and display the image seen directly on their LCDs. This makes the digital IR photography possible and much more convenient than the traditional film approach.

An IR photograph is usually manifested as monochromatic (B&W) when a true IR filter is used. There are also other IR filters (Hoya R72 is a typical example), which are not so opaque to prevent all visible light from coming into the lens and reaching the CCD or CMOS sensors. The colour processing arrangement and optical system inside a particular digital camera may cooperate well with the R72 filter to possibly generate an interesting special colour effect. Owing to the red light with a relatively long wavelength travelling through the filter, the image straight from the camera has a red or magenta colour cast. These colour components after filtration across the entire image form the basis of colour IR photography.

It is fairly easy to set up a custom white balance to clean up the reddish hue. This can be done either on camera during shooting or in a digital darkroom using an image-editing software package such as Photoshop. To shoot in JPEG format is often fine, but to shoot in RAW means a greater level of comfort for adjustments …….. Full Article.