RAW Photography: Who in the What Now?


RAW Photography: Who in the What Now?

RAW… for those in the know, it’s the only way to shoot when you’re rolling digital. For those not in the know, it’s usually met with a, “whoa, that’s a big file… and it kind of looks like dookie. Delete.” RAW image files are not “dookie”. They’re actually pretty amazing, comparatively speaking.

RAW files are often referred to as “digital negatives”, mainly because it’s about as useful as an unprocessed (chemically, that is) film negative (which is to say, very) and about as printable as a film negative is too (which is to say, not so much). They have almost all the information recorded by the image sensor (which I hope we’re all keeping clean) with minimal processing and compression being applied to it by the camera’s brains.

When you take a photo with a digital camera, regardless of what make or model, and save a jpeg, you’re left with a highly compressed, but printable, image file. The thing about it is that most higher end digital cameras, especially DSLRs, have the capacity to capture tons of data about the image you’re shooting with its image sensor. But when your camera creates that jpeg, it’s taking a lot of that data and throwing it out. That’s what compression is: deriving a smaller file size from a larger file while maintaining a semblance of that original file. This can be done with just about any file type (audio files, video files, image files, etc.). The issue is that there isn’t a tremendous amount of thought being put into the compression when your camera creates a jpeg. Don’t get me wrong, I love my camera, but I know it’s as dumb as a doornail when it comes to processing its image sensor’s data, calculating each pixel’s value and compressing that into a jpeg. I bought my camera for its brawn, not it’s brains. Trust me, you’re smarter. And as any photographer will tell you, having more control over your image is always better, even if it’s an option you don’t end up really exercising.

RAW files tend to look pretty flat, almost washed out, with little saturation or contrast and they haven’t been sharpened either, so they also look a little fuzzy. Part of the reason is that there is so much information to draw from in that file, but it’s really just what all that information looks like unprocessed. The fuzziness is a result of there not having been a sharpening filter applied. The flatness is a result of all that glorious detail in your shadows and light areas you didn’t lose, but that you would have if you saved a jpeg. Your camera actually does a lot of processing when it creates a jpeg. It just does a slipshod job of it.

All that’s what your really expensive camera is supposed to give you. That detail in your shadow and light areas is the fruit of “latitude”. Latitude is the measure of the ratio from brightness to darkness within which you can still discern detail without a loss of quality to the image. To look at it another way, there are two extremes in photography: crushed blacks and blown out whites. At either extreme you have no detail in the area that is crushed or blown out, it’s just solid black or solid white. Latitude is the measure of just how many stops you can squeeze between those two extremes. In digital photography that latitude comes in the form of “bit depth”. Ce tu parles? There’s math involved here, so bare with me. Your camera’s image sensor is capable of capturing 12 or 14 bits worth of information. A jpeg is an 8-bit file format. The more bits the greater the bit depth. The greater the bit depth the more leverage and thus latitude your image can have. Bit depth, in this sense, is a measure of how many values of luminosity a pixel can handle and potentially represent. So a 12-bit image sensor can record 4,096 values of luminosity, 14-bits can record 16,384, 8-bits gives you 256 (these are all, as you might be able to tell, multiples of 8. That’s because we’re digitizing something analog. Light exists in continuous waves (wavelengths); digital files exist in bits (non-continuous samples)). That’s basically a digital version of the measure of latitude; it’s being expressed in bits instead of stops. With a RAW file, you have the room to make larger adjustments to the exposure of the full image or parts of it before you start seeing artifacts and degradation in that image. That’s where you can really profit from all those values of luminosity in higher bit files. This measure affects your camera’s ability to reproduce colors as well. Since color is just a specific wavelength of light, and light actually has no color, image sensors don’t directly record color information. Sensors have red, blue and green filters (RGB) on specific pixels and, using a whole heap of math and computing where terms like “algorithms”, “demosaicing” and “matrixes” pop up, the information is processed to generate estimations of color bases on the luminosity of each of those color channels. That processing can happen in-camera and get spit out as a jpeg or one can preserve all that information in a RAW file and fully process it later with the help of some software. But when the camera does the work, you end up losing that unprocessed information and you’re just left with that jpeg. There in lie the benefits of shooting RAW. Not only are you doing a lot of the processing that your camera does manually, thus controlling it much more and to your exact specifications, but you can avoid doing some if the things that damage pixels.

Most DSLRs can save both a RAW file and a jpeg of any exposure at the same time. It’s a good exercise to do this and look at the difference between the two files before you process. You’ll find a lot more detail in your shadows and a lower propensity for over exposure in that RAW file (hurray latitude!). It just happens to look a tad “meh” when it comes out of the camera. All that is a good thing, because once you process the image it can look amazing, thanks to the deep pool of data you’re now drawing from.

So what exactly do you do with a RAW file? You process it of course! It basically slips another step into your digital workflow that you might not have had there, while at the same time putting parts of a camera-born jpeg workflow into that new step. At the end of the day, if you habitually edit your photos anyway (which you really should), it all evens out, time wise.

With a RAW file you need some sort of software that can do this processing I keep talking about. Photoshop (since CS2, at least) can do this with Camera RAW, which is a plug-in that opens up automatically when you open a RAW file, but there are a number of pieces of software out there that can accomplish this. The issue with all this, however, is that there is no such thing as a standard when it comes to RAW files. Not yet, at least. Cameras and scanners produce these files, and for each make and model there seems to be a slightly different file type. Companies like Canon, Panasonic and Nikon are constantly developing the technology and hardware in their camera bodies, and that means the software/firmware changes too. Every company has it’s own file extension for their proprietary RAW file type. But that doesn’t lay out the whole story, because for each company (say Nikon or Canon) that has their unique file extension (Nikon’s NEF files or Canon’s CR2 files) there are different versions of the file extension. So not all NEFs or CR2s are the same. You might notice that if you work on a Mac, your software updates often have something called the “Digital Camera RAW Compatibility Update X.XX” (the last one was 3.16, I believe). This is why there are a lot of those updates for you to download. For almost every new model of a camera a company issues, there is a new version of their proprietary RAW file format. This can be a hassle for a lot of folk who upgrade their cameras, but not their software, and I don’t mean just downloading that free update from Apple. For example, I used Adobe CS4 at home but CS5.5 at the office, and I work with a Nikon D7000. That was a problem if I ever wanted to work on something from home that I shot with that D7000. The RAW file format for that particular camera is completely incompatible with Camera Raw 5.2, the version of the plug-in in Adobe CS 4. There’s no way around it. In order to open an NEF from a D7000 you need Photoshop CS 5 or later so that you can use Camera Raw 6.3 or later because that’s version of the plug-in that will recognize the RAW files that camera makes. Que cosa fa, Adobe/Nikon/everyone else? The only solution for me is to have Photoshop CS 5 or later. Period. This is something that can pop up with any camera manufacturer and any older version of Adobe’s software. So keep that in mind when the time comes for a camera purchase. Now, all that being said, if you’re not running into this problem, what do you do with that software?

Lots. If you do any color/hue, exposure, contrast, saturation, sharpness, noise reduction, or white balance adjustments or even compensating for lens distortion, you’ll find you’ll do that in your RAW processing, with most pieces of software. If you’re going to retouch the photo (i.e. actually move pixels) you’ll do that in Photoshop proper, or whatever program you usually use for that.

Obviously there are a few drawbacks to shooting RAW. The obvious one is file size. You’re multiplying the file size by a good 2 to 6 times what a jpeg would be. But if you’re shooting a lot of images of the exact same thing, looking to find that one great shot, like say a model, it’s worth the space because you don’t necessarily need to keep every single shot. Also, drive sizes are increasing on what seems to be a monthly basis. You can buy a 128 GB memory card for your camera and a 3 TB drive for photos for a few hundred dollars today. That helps alleviate the storage problem. Besides that there is the fact that there is no standardization, which in and of itself poses problems, as I noted earlier. But that might not even be the biggest specific detriment to this lack of a standard. The big fear is that, due to the ever-changing nature of RAW file formats, one day a photographer might not be able to open his RAW files because support for this in software will be dropped.

There is a push to creating a standard file format, however. Adobe’s DNG RAW file format seems to be the most likely candidate at this point in time, but that by no means is a done deal.

Ultimately I’d shoot RAW. At the end of the day you have greater control, and you end up being able to save a pristine jpeg or TIFF that you controlled the look of, instead of your camera. If you really felt like you were hard up on drive space, I suppose you could delete them after you process them and save the image into whatever format you prefer, but don’t take that a recommendation. You just never know. You might want to do things very differently down the line, and it’s hard to put a price on the value of being able to go back to square one with a photo. In the very least you should try it out. Shoot RAW and jpeg simultaneously and play with both files in the postproduction workflow you prefer. See the difference.

May Hyperion shine favorably on your every exposure.