So yesterday I introduced the concept of JPG and RAW images.  If you’ve been into photography for a while or are aware of the plusses & minuses, then my apologies: one more repetitive post.  Today’s point is to expand on RAW images and what you have to go through to use them.  And why you might want to.

RAW.  Every camera takes RAW pictures in some way, even if it’s not on the spec sheet.  Every manufacturer has a different definition of what “RAW” is.  In most cases, it’s a variant on the TIFF standard – lossless, pretty bulky. Most formats are closed, meaning that they’re company secrets.  Typically, they store far more info than your typical JPG file.  I generally think of a RAW file as being something like a 3-layered JPG file: a separate TIFF for red, green, and blue colors.

That’s doubtlessly inaccurate (although it’s close to Adobe’s DNG format), but it kinda makes the point.  In fact, it’s probably more like a 3- or 4- layer image based on the CIELAB color space. Luminosity info is on a separate layer, and RAW format will save a wider range of that info.

To turn a RAW image into something that you can actually use, you have to run it through some sort of RAW photo processor.  I personally prefer the RAW converter that comes with Adobe Bridge. It’s fast, efficient, and gives pretty sharp results.  There are plenty of other options, mind you – but the end game is the same.  You do your own processing, and you save to a shared (usually JPG) format.  Only here, you can control everything about the end result.  For example, since you can change the photo before processing you can also change the exposure.  Were you off by 1/20th of a second?  A slight tweak to a slider & there you are.  Come back a week later – you want it to be darker, moodier?  Slide that slider the other way.  One image, many interpretations.  You can do it with a JPG, but it’s not as easy, and damages the image.

So, RAW photos are larger, take up more memory, and can’t be immediately used.  But they store more info, and much more info can be pulled out of them.  An example from my SLR:

A high-dynamic-range photo from a photoshoot in a near-ghost down in Nevada, 2008

This was taken in the desert, around 3pm.  A very bright day, with a very dark interior.  If you shoot with normal exposure, the windows get blown out – just too bright.  Expose for the windows and you lose all of the detail inside the room – it’ll come out too dark.  But a RAW photo, somewhat in the middle?  That can be tweaked after the fact, which gave me something like this.