Sunday, 28 November 2010

The value of raw

There are some who argue that shooting RAW does not have much benefit over larger file jpegs. The RAW file can be considered at the digital version of a negative; it holds all the information captured by the original camera settings and these can be of real practical value. These settings can be manipulated later using RAW conversion software and some of these features are not available in photoshop or other photographic software. Reading the following two articles was interesting as they argue from both sides of the fence.

Luckily I am able to access a friend's vast personal library of photography books on many topics and have temporarily borrowed Camera Raw with Adobe Photoshop CS, Bruce Fraser Copyright 2005 Peachpit Press, RAW 101 Better Images with Photoshop and Photoshop Elements Jon Canfield Copyright 2005 SYBEX Inc and RAW Workflow from Capture to Archives, Philip Andrews, Yvonne J.Butler, Joe Farace Copyright 2006 Elsevier/Focal Press.

As ever it is impossible to sit and read huge chucks of such detailed technical books, many of the techniques they begin to introduce you can only grasp when undertaking the practical, but it has given me a greater understanding as to why RAW can be such a powerful tool and I can see that given the opportunity I will enjoy sitting and "playing,"

These books explain how raw differs from JPEG, and how to exploit those differences. One of the best things about shooting raw is the freedom it confers in imposing your own interpretation on your images.

Raw capture, gives you total control. I have a tendency to do the barest minimum in RAW and then fix things Photoshop as this is something I know and it is my comfort zone but Bruce Fraser likes to point out “the fact is that Camera Raw allows you to do things that simply cannot be replicated in Photoshop.”

Fundamentally, a digital raw file is a record of the raw sensor data from the camera, accompanied by some camera-generated metadata, a record of the sensor data.

So why shoot raw? It is something asked by many photographers and the authors of these books. As stated already, the basic answer is simply, control. When shooting JPEG, the camera's on-board software carries out varies tasks to produce a colour image, then compresses it using JPEG compression and you get locked into the camera's interpretation of the scene. With raw, the only on-camera settings that effect the captured pixels are the IS0 speed, shutter speed, and aperture. Everything else you can control when converting the raw file.The white balance, the colormetric rendering, the tonal response, sharpening and noise reduction and, within limits, even the exposure compensation can be re-interpreted.

You also produce a file that can withstand a great deal more editing in Photoshop than an 8-bit per channel JPEG. Edits in Photoshop are "destructive"-when using tools such as Levels, Curves, Hue/Saturation, or Colour Balance; the actual pixel values are altered.

Having extolled the virtues of RAW there are limitations; you have to take the time to process the raw file to obtain an image. Some professionals, for example wedding photographers and photojournalists will not use RAW due to time constraints.

Raw files are larger than JPEGs-typically somewhere between two and four times as large. This becomes an issue with both storage and the size of memory card you use. Another important issue with raw files is the use of proprietary formats for raw files, and concerns over their long term readability.

It will be interesting to undertake the exercises with regards to RAW to see if I still will be so heavily on the side of shooting in RAW.

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