RAW vs. JPEG
Ah yes, the age old question. Does a digital camera, like a Canon 20D, take better photos with RAW mode, or JPEG? Some swear by RAW. Others say it doesn't make any difference. There are technical comparisons aplenty on the Internet - just Google for some. But the only way to know for sure is to try a few experiments. They don't have to be precisely controlled (after all, I don't often go out to take photos in a precisely controlled environment) but they do have to represent real world scenarios and image captures. Straight to it, then...
Details in the Highlights
Tina and I went out for a day in Bourmemouth, and I ensured the camera was in RAW/HQ-JPEG mode. That is, for every shot, it saved both the RAW image data and the best quality JPEG variant of that image. I had the camera set to "Parameter 1" settings, which applies a little saturation and sharpening. Here's a shot, RAW version on the left, and JPEG version on the right:
The RAW image was resized and converted to web-friendly JPEG format by ACDSee; the JPEG version was just resized. I don't know what parameters ACDSee used to do that RAW to JPEG conversion, but it doesn't really matter. This is just an illustration, and the lesson learnt is obvious: the JPEG version is crap. The background is completely blown out and the image appears over exposed. It couldn't really be rescued either - that background (which is actually the sunlight reflecting on the sea) is mostly pure white, and is therefore useless. On the other hand, you can see the camera JPEG conversion at work in the jumper - the colours are much brighter - and there's more contrast in the sand.
That blown background ruins the shot, but fortunately I have the RAW image data which contains more detail where the sunlight is playing on the sea, and more detail where the sea meets the wet sand. It needs plenty of work doing with the colours, of course, but it looks like a usable shot from the RAW data.
I imported it into Photoshop using v2.4 of the RAW data filter, following a workflow recommended by Bruce Fraser in his book "Real World Camera Raw with Adobe Photoshop CS", then did my usual colour tweaking and sharpening workflow. Here's the result with the camera's JPEG image again on the right:
Still not great because the image was over exposed to start with, but there is more detail in the background, and the colours are definitely more accurate than what the camera produced. I probably could have tweaked and sharpened the camera's JPEG image to get the colours in the jumper and sand close to how they should be, but there's not much I could have done with the sea.
Details in the Shadows
Read up on any technical discussion on the advantages of RAW over JPEG and you'll very quickly come across the argument that RAW images contain more detail in the shadows and dark areas. Technically that makes sense, but if you don't understand the reasons, you should at least see the difference between these versions of this rather dull shot, taken in Rome. The top one is the RAW image, again resized by ACDSee:
It was one of those crisp, cold days, with dazzling sunshine and a bright blue sky - perfect for heavy shadows (and showing off dust on the sensor :o}). The colours in the JPEG version are pretty much spot on here, but the amount of extra detail in the RAW version of the image makes it a much better starting point for a retouch job. The result of that retouch job is below, processed RAW image top, and the camera's JPEG image again below it for comparison:
Looking through all the shots I took in Rome over that bright weekend (about 350), this is the most dramatic example of how RAW captures shadow highlights that the camera's JPEG compression looses. There were plenty of other shots, however, that will come out better being processed from the RAW than the JPEG. RAW images holding better shadow detail is no myth.
Here's another shot to ponder. This one was taken in the old city of Pompeii (you must go if you get the chance, it's an astonishing place) on a bright, cloudless day. As usual, ACDSee's RAW version is top:
What the heck has the camera done to the sky? It was blue, not cyan! This was taken with auto-white balance, which is my usual setting, and I'd have thought that a crystal clear day in southern Italy would have been an easy one for the camera to work out, and therefore get good colour reproduction. Obviously not. Maybe the shadows threw it. Quite a lot of my Pompeii photos came out like this, so it's not as if it's an isolated bad one.
When I first got the camera I shot a few RAW+JPEG images and looked hard at the photos trying to see where JPEG artifacts were being introduced. I couldn't see any at all - at high quality mode the JPEG compression is so weakly performed there isn't any practical difference between RAW and JPEG for the vast majority of images. I figured that I should take another look if ever I progressed to studio work, but for what I wanted the camera for, RAW mode was pretty much useless.
I was, of course, looking for the wrong thing. It's image detail that's the issue, not JPEG artifacts, and the fact is that RAW images do contain more detail than JPEG ones. In many cases, maybe even most cases, the JPEG image is plenty good enough and the extra effort involved in processing the RAW file isn't worth it. But it does seem that having the RAW data will occasionally allow me to make a poor image into a usable one, or a good image into a great one.
I suppose people have to draw their own conclusions really, based on their own photographs, created using their own techniques and equipment, but for me the conclusion was simple. RAW undoubtedly captures details and accuracy that is lost when the camera does its internal JPEG conversion, so I'll be shooting in RAW+JPEG mode from now on.
Derek Fountain - 25th November 2005
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