Tuesday, February 06, 2007


I Love RAW...

Yeah, I know what you're thinking... WWE! But no, we're talking about Digital Photography today, and 'RAW' is the RAW image format!

Welcome to the world of Digital Photography, a world where Negatives have been swapped for sensors, film grain has been swapped for noise, where ISO and Colour balance are no longer difficult to deal with, and where the photographer processes his own photographs! It's a great place to be in, and photography has never been as exciting as it is today!

So where does RAW fit into all of this? To explain that, I'm going to have to get into some of the basics...

Sensors and things like that

Digital Cameras capture light using either a CCD or a CMOS sensor. Sensors are made up of tiny photo-receptors that are sensitive to either Red , Green, or Blue light. The images that we see are a combination of different intensities of these three basic colours.

The information from these photo-receptors are processed by an image processor microchip and are encoded into JPG or TIFF format files that we can see on the LCD of the camera or on a computer. There are some disadvantages to this method of obtaining 'finished' image files ... let me list them for you.

  • Further tweaking of the image after it is saved as a JPG or TIFF results in some loss in the tonal range of the image and increased noise levels in some cases.
  • If your white balance mode is not set correctly, you could have one hell of a time trying to correct it and when you do, you'll have a relatively noisy image ... bad, bad thing to do!
  • Highlights that are blown (overexposed without much detail) can never be recovered.
  • Any edits on the file are destructive edits. Meaning that once the file is modified and saved, the change to the pixel data is permanent and cannot be reverted. This, coupled with saving JPG files is a designer's recipe for bad image quality!
RAW to the rescue!

Now, how does RAW help you overcome this?

The smart people among you would have realised by now, that the 'RAW' file format gives you the raw, unprocessed data thats recorded on the camera's sensor. This enables you to forego the camera's built in image processing algorithms (also called de-mosaicing algorithms) and use one that you prefer. Personally, I prefer Adobe's Camera Raw plugin and Phase One's Capture One Pro software... They give me more control over the white balance, the amount of sharpening applied, access to the "curves" and "levels" tools, and the option to use different colour spaces and bit depths.

Even more impressive than this list of +points, is the fact that all the changes that I make are not directly to the actual RAW file, but to a settings file or database... This means that if, at a later date, I decide that I don't like the way that I've processed the file, I can go back to the file, revert to the original image and process it all over again (believe me, this will happen to you...). It also means that I can get different looks by processing the same image in different software.

Think of it as a Digital Negative! In fact, that's what Adobe is calling their standardised RAW format, the DNG format... There are some issues about the standardisation of raw formats at the moment because different manufacturers use different standards to define raw files... but that is something that we can discuss at a later date... for now, lets talk about RAW's problems.

One of the major setbacks that photographers will face with the RAW format is the large size of RAW files. JPG files on my Canon 5D come to about 4MB while RAW files come to about 12-13MB with their automatic compression enabled. This means that it will end up eating away at those megabytes on your CF cards and Hard Discs much faster than JPGs and storage and archival will eventually become an issue.

I swear by RAW

Evenings [on the banks of the cauveri] [forgotten wayside temple]
However, the benefits far outweigh the problems when it comes to RAW, and as an advanced amateur and a professional photographer there are immense benefits to the creative workflow... click on the images to see what I mean...

Try out RAW today if you have it on your Digital Camera... photography becomes all fun, and no work...

Have fun!

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