World Photo Adventure - To use RAW or not to use RAW

To use RAW or not to use RAW

To use RAW or not to use RAW….

…..that is the question. The subject that causes the most arguments and flame wars on photographic forums is the great Digital v Film discussion. But running it a close second is the RAW v jpeg debate.

RAW advocates normally blast off with “jpeg is a ‘lossy’ format”. Fine, it is. But I have never seen a demonstration with an actual side by side print comparison that shows the extent of the ‘loss’. The next salvo is colour balance. O.K. but as a black and white merchant I can stand aside and ignore that one. “Ah!” exclaim the RAW advocates “The exposure you gave initially can be changed.” Yes so it can, but surely any photographer worth his salt should have assessed the subject and exposed accordingly? Then the jpeg merchants point out that saving huge files on memory cards mean that we are talking mega sized files and cards which correspondingly cost mega bucks to buy. Partly true, however memory just gets cheaper and cheaper. So where do I stand on this subject? Firmly and squarely in the middle.

As far as I am concerned the only RAW argument that applies is the exposure question. In the good old days of black and white film the landscape photographer would still come upon the subject where the film latitude wasn’t wide enough to cover the subject. So we exposed somewhere in the middle and trusted our processing and printing expertise to get us off the hook. O.K. usually it meant a bit of burning in of the sky area, or holding back the foreground. Unfortunately we can’t do this with our inkjet printer. And forget about the latitude of FP4, digital is comparable to Velvia.

But the RAW guys and gals have the answer when it comes to problems with latitude. The biggest single advantage with RAW is that although on screen it might look as though the highlight have ‘blown’ but within limits they haven’t, they can be retrieved. Most RAW converters allow the exposure to be changed in the range of around +/- 3 stops. So in the example below an average exposure was given. The sky, although a bit cloudy, was much brighter than the house front. I took an average exposure reading and realised that a bit of post-processing would be required. But of course whilst the sky would need reducing the house fronts would need lightening. No problem. In the RAW converter you can’t give an area one exposure and another area a different one you can only work on the whole image. Therefore with subjects like this RAW will help to retain highlight details (the shadow areas can be sorted out later in Photoshop.) With digital once detail is lost it’s gone. If jpeg is used for the initial capture no amount of P.S magic can retrieve it. So, go ahead and shoot the scene overexposing the bright areas and underexposing the shadows. Place your exposure in the mid range within the ‘latitude’ of the digital process. But remember, the placement of your exposure must be just as accurate indeed perhaps even more so then with film. Under-exposure creates digital “noise”. Later in the digital “darkroom” load the file into your RAW converter of choice, reduce the overall exposure by 2.5 stops, hey presto the sky has appeared, the house is very dark and gloomy but what the heck, now, time for Photoshop.

Once the file is displayed in P.S. we can work on the rest of the exposure. I find with digital it helps to pre-visualise the scene that you wish to photograph bearing in mind yours and P.S. limitations. With the example below the lovely clear edge of the roof tops it would be very easy to select the foreground with the lasso tool, for more complicated shapes the “magic wand” is perfect. You will normally find that by playing with the range of the “magic wand” you can get it to select the required area, even if you have to temporarily alter the monitor brightness to help. Then once the area has been selected apply any adjustment with “levels” or “brightness and contrast.” Another little tip here is that while the foreground area is selected do the sharpening, then reverse the selection back to the sky and apply a bit of “Gaussian blur”, especially if you are going to make a large print. Doing this avoids any digital artefacts showing in large areas of even or subtle tonality.

RAW versus jpeg

The illustration on the left is the original digital capture with the exposure placed to give the least exposure to the brightly lit sky, yet enough to capture the shadow detail, in fact placing the exposure within the limits of digital latitude. That latititude can be expanded by the use of RAW capture and PhotoShop wizardry to give the properly exposed print on the right.

The right hand image shows the final result. The sky was enhanced by cutting down the original exposure, thus revealing all the detail which, although present in the RAW capture wasn’t apparent on screen. Then the selection was reversed and the exposure effectively increased to compensate for the original under exposure. A little click of the “Unsharp Mask” and Hey Presto, it’s done.

To sum up. Treat digital capture exactly as you would film. Experience will tell you how much over-exposure will still ensure detail is retained and how much overexposure will be captured without creating noise. Then simply place your exposure to encompass both limits. Sort of Zone method without the fuss.

So the answer to the original debate: RAW or jpeg? In my opinion if the subject brightness range is extreme, extend the digital latitude with RAW. If not, why bother? Get more piccies on your memory card, and stop worrying about it. RAW is just another tool.

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