RAW photos have three other aspects that should be considered when choosing JPEG or RAW formats: One is future compatibility, the second is future processing enhancements, and the last is to factor in the quality of any changes you might make to your photos in post-processing.
The future of RAW
You would do well to consider one very important aspect of the RAW format: Will this format be supported and readable in the future?
RAW format is proprietary. This format is not a standard and cannot be read except by those programs which have special enhancements. Programs such as Adobe Lightroom and Photoshop, as well as some other advanced image processing software have periodic updates that grant them the ability to read these formats. You will notice that when a new camera model is released, there is often a lag of several weeks to months before an update is available that enables these programs to read the RAW formats the new cameras produce. Until then you must either record in JPEG – or whatever other standard format the camera allows – or else use the software that comes with the camera to interpret their own proprietary RAW image format.
So what happens in 20 years? Or 50 years? Or 100 years? Will all of these special formats still be supported? Kodak just announced that they were getting out of the digital camera business. What happens to all of those Kodak digital camera RAW formats? How long can Adobe afford to maintain a library that includes Kodak RAW formats when the cameras are no longer being made? What about the Big Names – Canon or Nikon, for example? Surely their formats will always be able to be read, right? Maybe; Maybe not. Look at word processors. Can you find any program that still reads some of the early word processor documents, such as Lotus Notes, or PFS Write, or Brother Style Writer? These were very popular 20 years ago, but you can’t even read those files today without 20-year-old software. Think it couldn’t happen to Canon or Nikon? Nikon itself can’t read their own proprietary formats from some older cameras. How long can a third-party, such as Adobe, afford to support formats for cameras that weren’t manufactured for 20 years; or 50 years; or 100 years?
You want your photo format to last at least as long as you do, and preferably to readable far into the future. Using Camera RAW, you might not be able to open those files in 20 years.
So have we finally found the RAW killer? If I was going to archive my files in RAW format, then that might indeed be the death knell of RAW format, at least insofar as long-term storage was concerned.
Fortunately, Adobe is providing a solution that hopefully will address this very issue. DNG (Digital NeGative) is an open-source format for storing RAW images. This means that you can convert your camera’s proprietary RAW image format into Adobe’s DNG format and your RAW image is now in a standardized format that is open-source, which means that the format is public information and so has an excellent chance of still being readable in the foreseeable future. This format has been adopted by Adobe (of course), and will hopefully catch on. As of the end of 2011, 12 camera manufacturers have supported DNG in-camera in 38 camera models since its introduction in 2004. Manufacturers such as Casio, Ricoh, Pentax, Leica, and Samsung have all made cameras that will store their raw images in DNG format right from the camera. Over 230 camera models so far can have their RAW formats converted into DNG format. This is a powerful endorsement of the DNG format and should address the forward compatibility issue. (I will examine the DNG format in more detail in a future article). Adobe Lightroom has a feature that can automatically perform this conversion when you initially import your photos, so the process is fairly painless and invisible.
The take-away here is that if you want to keep your camera images in a RAW format for years, if not decades, then give serious thought to converting them to DNG format. If not, then I will strongly urge you to keep your archived images in JPG or other standardized formats as proprietary RAW compatibility decades from now is a risk you do not want to take.
Technology Doesn’t Stand Still
Once you take your picture, are you done? Is that the best possible picture you can get? The tools keep changing and improving as time goes on. What was state-of-the art a few years ago may look somewhat shabby in the future. Image processing is changing and if you don’t have your best possible source data to work with, then your past images will never look better. For many people, this is not a problem. Many people will take their vacation photos, print them once or post them on a website and never look at them again. On the other hand, how many of us have had that one photo that we wish was better. It was almost good enough. If only it wasn’t so dark or the contrast wasn’t so high or the colors weren’t so washed out. Well, these photos may be salvageable using current technology. But it is possible that some future technology may be able to process them even better than we can today. RAW format will give you the option to revisit these photos in the future and perhaps turn a poor photo into a real keeper.
Here is a photo that I took of a Canadian Goose in flight. Because of the bright sunlight, the photo has very high contrast, which makes the shadows on the underside of the bird very dark and much of the detail is lost.
Using the RAW processing technology available to Adobe Lightroom in 2003 (left images), you can see that it is possible to pull more detail out of the photo. Although this photo is much better than the original, you can see in the bottom detail how a strong purple fringe appears. Even in the original photo – reduced as it is – you can see evidence of purple fringes around the wing tips.
In 2010 (center images) you can see much better detail in the shadows and in the bottom enlargement, you can see how the details around the beak and eyes is much more visible. But you can see an even stronger purple fringe around the wing tips. This is really an extreme case where the shadows were really pulled up tremendously. In most photos where shadow detail is only modestly enhanced, there is much less fringing visible.
Now, in the 2012 version of Lightroom (right images), you can easily see the improvement that this version has over the version that was just two years old. The detail in the eye and beak is much improved and, looking at the detail, the purple fringing has been tremendously diminished to just a purple shading around the edges, which is almost invisible in the wing tips.
The final consideration is your post-processing needs. Apart from the improvements that may occur in the future, post-processing imposes its own needs which RAW can satisfy better than JPEG.
If you look at the color histograms, you will see the difference between a cool white balance setting, such as Tungsten vs a warm white balance setting, such as Shade. The cooler white balance compresses the red and information to the left, while shifting the blue range somewhat less and to the right. You will also notice that the upper and lower ranges for the blue and green channels is pulling in much more information in the cooler setting (although it is compressed more) than in the warmer setting. The warmer settings tend to expand the color information over a broader area, but tends to drop out the highest and lowest information.
The result is that if you are using a JPEG image, you just don’t have all of the information to properly change the white balance. If you make the image warmer, then you have to expand a smaller range to fit a larger one and the mapping won’t be smooth. If you move from a warmer image to a cooler one, you are missing information that was discarded when the JPEG was first created. This is why you cannot effectively perform white balance changes as effectively from a JPEG image. In a RAW image, all of the original sensor data is still available, so the computer can re-balance the three color channels for a smooth distribution with no missing data either at the ends or in the middle.
When you modify an image, as I did here, if your image is in RAW format (center), then you have access to all of the sensor data. If your image is in JPEG format (right) then it only has the information that was already in the image to start with. If you enlarge this image, you will be able to see a clear difference in tone smoothness and color in the RAW image compared to the JPEG image. Why is this? It’s because in pulling up the exposure in the dark areas, the RAW processing is pulling in information that was lost in the JPEG image.
As you can see by this image sequence, when brightening up dark areas in a RAW image, the lower end of the histogram is nice and smooth, which is indicative of the system pulling in low-light information from the sensor that was not originally included. Compare that to the histograms of the JPEG image. You can see on the left side of the histograms that the lower light levels are choppy rather than smooth. This is highlighted by looking at the far right column in the display. This is an overlay of the JPEG vs the RAW image histograms where you can see how much difference there is in the lower light information between the two. The small, thin area of difference over the entire histogram is simply due to different editing to make the images look good – the same settings just don’t work well with JPEG as they do with RAW and vice versa. However the large highlight difference on the left of the difference histogram column is due to the fact that RAW can pull in more valid data from the file, whereas the JPEG image just doesn’t have the information available and can’t produce as good looking change when brightening up dark areas.
Camera Profiles in Post
One last consideration for using RAW is that your image processing software (Adobe Lightroom and, thus, Adobe Camera Raw) may have profiles that are available from your camera manufacturer that can modify a RAW image to use a variety of camera profiles, each of which has a particular look to it. For my camera (the Canon 60D), I have been provided with five alternatives to the default Adobe Standard profile. These differences can be simulated using various settings, but they may contain characteristics that could be difficult or impossible to fully emulate just using the Lightroom settings.
- Camera Faithful has rather less contrast than Adobe Standard
- Camera Landscape is more saturated in the blues than normal
- Camera Neutral is similar to Camera Faithful
- Camera Portrait has warmer reds
- Camera Standard is just a little brighter overall
All of these choices also have subtle differences in color that would be very difficult to reproduce using the image controls, as they draw from the entire gamut of image data that was recorded by the sensor. With a JPEG image, you might be able to specify an image style, similar to the profiles your camera manufacturer provides to process RAW files, in-camera. But if you are shooting JPEG, then those profiles are embedded in the image itself and cannot be changed.
As this example image shows, the difference a simple profile change can make in a RAW image can be significant. No other modification was made except to change the camera profile. This adds additional flexibility to RAW that JPEG cannot match.
Raw IS Better (but is it worth it?)
Without a doubt, RAW is a better file format if you are going to edit your files, but is it really worth it? The RAW image shown above (in DNG format) was 16.6 MB in size, while the JPEG image was only 4.9 MB. The question you need to ask yourself is whether the benefits outweigh the size. Storage space is cheap and always getting cheaper, but even so, this is an enormous difference in size. The truth is, if you are shooting in a low-contrast environment, using the correct white balance, then there is probably little or no advantage to using RAW. Even in the fairly extreme cases shown in this review, JPEG performed surprisingly well. On the other hand, if you are shooting a relatively small number of photos, or shooting in a high-contrast environment, or plan on doing significant post-processing of light, then RAW may still be your best bet.