We haven’t had any photo questions these past few weeks and without questions I have run out of ideas for Shutterbug 101. But from one of my other desert forums came the question, “What is RAW data and why do you like it.”
Basically RAW means exactly that, it is the unadulterated, unprocessed image data from the camera — hence the word raw.
“When a digital camera makes an exposure, the imaging chip (whether it’s CCD or CMOS) records the amount of light that has hit each pixel, or photo site. This is recorded as a voltage level. The camera’s analog-to-digital circuitry now changes this analog voltage signal into a digital representation.” says luminouslandscape.com. But what does that really mean.
It means that when one shoots an image, all that information is gathered by the sensing device and recorded without changing anything except from analog to digital.
It doesn’t concern itself with sharpness, color, etc.
If the settings are adjusted in the camera by the user (or the camera) such as white balance, sharpness, digital zoom, image quality, etc. then those settings are applied to the raw data, compressed and saved as a jpeg onto the memory card — it is no longer unprocessed by the camera therefore it is no longer RAW.
When saved as a jpeg there is data loss and image quality loss.
When one shoots RAW, then all the choices to be made: white balance, contrast, color, sharpness can be adjusted in post-processing software like PhotoShop and other programs, by the photographer. If your camera is capable of shooting RAW, the software to convert those images into either TIFF or PSD formats for final processing should have been included with camera. The conversion produces fairly big file sizes.
I know you are probably thinking, “what a pain — why would I want to shoot RAW? Too much work or hassle.”
Because you have greater latitude in determining the final print size, color, brightness and contrast. And more importantly, you are getting all the quality your camera can produce. You are making the decisions in the photo instead of the mathematics inside the camera.
There is a learning curve with shooting RAW but it is not insurmountable and well worth it.
If one makes an error, let’s say, in exposure, it is easier to correct when you have the RAW data to work with. And mistakes are made, trust me on that one.
While some say the downside of RAW is the large file size, I say that is its upside. I can create much larger prints from my 46 meg files than I could create from a jpeg of the same image which would come at about 23 megs. I also have more color information to work with.
When shooting RAW, I save all the good images in their original format. That enables me to play with the photos over and over without any degradation of the original pic. As soon as I convert and save a RAW file I have a .psd format — Photo Shop Document. My original photo is still just the RAW data awaiting any other conversions I might want to make.
For example, what if you are shooting a scene that has really bright highlights and very dark shadows. It is impossible to adjust a jpeg of that pic and get an acceptable quality image.
But if one shoots RAW, one can convert the same photo twice: once for bringing detail to the highlights and once for opening up the shadows.
The two images then can be sandwiched together to make the final image that has good detail both in the highlights and shadows.