"What The Heck Is A RAW Image File?"
Article explaining the difference, advantages and disadvantages of raw image files.
As I come from a sort of old school of thought in regards to photography (i.e. Film instead of Digital), I remember first hearing the term ‘RAW image file’ and to be honest I felt a bit out of my depth. Before that moment I had always seen a direct correlation between digital and film based photography. However, I understood the basics. That it was a larger file size and that I could potentially do more to the image after I took it, like in Photoshop, before saving the image a bit smaller in jpeg format or something similar.
This was enough information for me for a while; however, I must admit I rarely used RAW for a few naïve reasons. Firstly the hassle of downloading the file, this hassle varies from person to person as it directly relates to their camera and what format their camera saves the file as in RAW format.
Let me explain in regards to a couple of the most popular cameras. If you are using a Nikon camera it saves a RAW image file as a NEF (Nikon Electronic format) file. This is a file type that was designed by Nikon and therefore you will only get this file type when taking a picture in RAW on a Nikon camera. However, there’s no uniform standard of NEF files, meaning that every model of Nikon camera has a different type of NEF file format. Because of this most software packages like Photoshop will not automatically be able to read a NEF file as a RAW image file. So when you want to open such files you will have to download a plug-in. A Plug-in is a bit of software that tags on to your current software (like Photoshop) converting the file information in terms that your current software can read. Your only other option is to use Nikon image manipulation software. Often your camera will come with this anyway. The drawback is that more times then not the software is limiting in its capabilities, therefore it’s really worth your time to download a Plug-in from the Internet to use with your current photo manipulation software.
A lot of the most popular camera brands out there have adopted the same rule of thought in regards to what extension they use for their RAW image file; Cannon and Sony to name a few. I have read articles that point out that it would be a lot more helpful to have an industry standard for RAW image file extensions, in doing this software could potentially be able to read RAW image files from any camera. DNG (Digital Negative) is an extension that has been proposed to act as the industry standard for RAW image file extensions. This brings me to my favourite topic, Pentax.
Ok so I must say that I am a devout Pentax user, I am sure that if you continue to read my blogs I will consistently refer to Pentax, as it is in my opinion the best brand of camera on the market. Pentax are probably the most widely recognised brand that has started a revolution by not using their own encrypted RAW image file extensions. Pentax digital cameras save their RAW files as DNG, and thankfully DNG is already readable by most image manipulation software. Most versions of Photoshop for instance will automatically read a DNG file as a RAW image, thus taking out the hassle of downloading a plug-in, or having to use their brands own sub-par software.
Another reason why I didn’t use RAW image file capture when using my digital camera was because I simply did not understand what difference it made. To me I saw that it made a larger file, but I rarely print my images so this was of concern, and besides, it took up so much space on my memory card that I often could only get 50 to 60 images on a 1 GB SD card where I would get over 200 capturing in JPEG. But as I continued to develop as a photographer, and started rubbing elbows with other photographers I realised (as I was told consistently) that capturing in RAW was really the best thing. This lead me to do a bit more investigation and what I found converted me from always shooting in JPEG to now where I always shoot in RAW, So now I will get down to the main topic at hand:
“What the heck IS a RAW image file?”
For those of you that have used film and understand how it works, the best way to describe a RAW file is as a digital negative. By this I mean that the file holds ALL the visual information that existed when taking the picture. Just like when using a negative it is after you take the film (or SD card) out of the camera that you then can manipulate it. Many photographers refer to programs like Photoshop as a “digital darkroom”. That is to say that you will be able to develop the image digitally. I know to many of you this is quite difficult to understand (especially if you have not used film). How I explain this to students in my class is this:
Photography is all about capturing light. Try to imagine that every colour, therefore, every bit of visual information burns into film (or your image sensor) at different temperatures. If you then zoomed right in on it you would see what looks like a mountain range of visual information. Every peak and trough would carry information like, white balance, exposure, aperture, shadows etc… al created by whatever settings you set your camera to when taking the image. When you take an image in RAW and then transfer it to your computer this mountain range is fully in tact and therefore can be manipulated. When you open the file you should be able to adjust all the information to create an idealized image without affecting the image quality.
Now if you were to take the picture in JPEG format what you would happen is that all those peaks and troughs that are created when you create the settings in your camera would then be flattened. Imagine you take a piece of glass and flatten the mountain range… you will still see the image but all those peaks and troughs are now stuck in the position in which was created when the file was taken. What then happens if you open the image on your computer? Well, you can still manipulate it to a degree, but because certain visual information is not changeable you will ultimately have a loss in quality with the more you try to do to the image. This can result in pixilation or colour shifts, and over exposed areas, to name a few.
Don’t get me wrong there are a few good reasons to use JPEG files when shooting, and I have used it on occasion. Say you are going out on a really sunny day and you have taken a few test shots in auto mode and they look fine, and maybe you are only going to be pasting them to your Facebook page. In these situations maybe being able to take a quantity of photos would be more important then optimizing quality. So I would suggest using JPEG shooting mode in these situations. But if there’s any possibility that you may want to alter your photographs after the fact always use RAW. In my opinion the benefits will always outweigh the drawbacks.