{"id":144,"date":"2009-03-04T11:08:58","date_gmt":"2009-03-04T02:08:58","guid":{"rendered":"http:\/\/paulgoodchild.net\/blog\/?p=144"},"modified":"2011-11-22T23:58:11","modified_gmt":"2011-11-22T23:58:11","slug":"digital-photography-concepts-camera-raw","status":"publish","type":"post","link":"https:\/\/paulgoodchild.me\/blog\/digital-photography-concepts-camera-raw\/","title":{"rendered":"Digital Photography Concepts: Camera RAW"},"content":{"rendered":"

This topic is discussed and questioned all over the web, so why do I feel the need to talk about it here?\u00a0 There’s just something not intuitive about some attempts to articulate it…\u00a0 we all have different way to describe things, so the more explanations out there, the better.\u00a0 Hopefully this will help clear up any\/some understanding gaps for you…<\/p>\n

Before the days of digital sensors, the main medium used for photography was ‘film’.\u00a0 This film is a thin strip of plastic upon which are laid silver-halide crystals that undergo a photochemical reaction upon exposure to light (electromagnetic radiation).\u00a0 This reaction is what forms the basis of film-based photo capture.\u00a0 The film is then ‘developed’ using various chemicals in a controlled environment to produce ‘negatives’, which are used as the template for the prints that are typically produced in a lab.\u00a0 As long you retain these rolls of negatives you have the ability to re-print as many copies as you desire.\u00a0 The negative roll doesn’t change, it cannot be edited, and is a representation of the light that hit the roll of photosensitive film right back when the shutter was clicked.<\/p>\n

In the same vein, Camera RAW files are the digital equivalent of these film negatives.\u00a0 Basically light hits the photosites on the camera sensor, each site produces a signal and the camera processor interprets and stores the firing of these sites.\u00a0 With the appropriate software, the stored data that is the collection of these fired signals (RAW files) can be interpreted and output as an image either on-camera or on your computer.<\/p>\n

As with negatives, these files don’t change and cannot be edited – at least the image data can’t be changed.\u00a0 So how does that differ from the JPEG files you get on your camera when you normally take photos?<\/p>\n

In a big <\/strong>way.\u00a0 Or rather a lot of big ways.\u00a0 It may help to describe briefly what happens when you go from snapping a picture to receiving a JPEG image in most all digital cameras…<\/p>\n

You click, the image is captured by gathering up the sensor data at the photosites, the colours are determined and a RAW image is created.\u00a0 The in-camera processor performs some post-processing such whilte-balance adjustments (based on what it believed the surrounding light to be at the time of capture), image sharpening, contrast and brightness adjustments and of-course, noise reduction.\u00a0 As it does this, it scales down from the RAW data range to fit the JPEG data range.<\/p>\n

This JPEG image file is what the digital camera processor believes, given the settings you specified (if any) and the surrounding environment, what your final image should look like.\u00a0 If you want to edit it afterward so that it reflects what you<\/em> saw, you need to consider the limitations you’re faced with.\u00a0 So what are the primary differences between camera RAW and JPEG?<\/p>\n