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In terms of image quality, RAW has a definite advantage over other recording formats. This does not mean, however, that you should select RAW for every subject and in every situation. RAW naturally has strengths and weaknesses; the best way to optimize the benefits of digital photography is to fully understand the individual characteristics of all recording formats, so you will know when to choose RAW, and when to switch to JPEG.
Since RAW data is undeveloped, it must always go through a development process to create an image. Normally we think that digital cameras require no development process, but the truth is that JPEG data is instantly developed within the camera to produce a photographic image. Because it’s a split-second process, it seems that no development process is needed, compared to the time-consuming development process required for film cameras.
One definite disadvantage of the RAW format is the time and trouble required by the data-development process necessary to create the image. Since this development is usually handled on a personal computer, this also means that you must set up the system and learn the essential processing skills.
Some may think that this process is actually an advantage of RAW. You can spend more time and be more meticulous about image development because you personally develop the RAW data. Imagine that you are planning to retouch an image after shooting. With a JPEG-format image, retouching is in fact the second development, because you are actually redeveloping an image previously developed by the camera. If you want to retouch a captured image, you should definitely choose RAW, rather than doubling the development process and causing a deterioration in image quality with JPEG. We studied this interrelation between the image development process and image-quality deterioration last month, so you should be familiar with this by now.
Colors in a photograph are reproduced during the development process. That means that undeveloped RAW data is not a photograph, because it has no colors in it. You add colors to RAW-format images only by developing them.
One big advantage in RAW-format shooting is that you can leave the white-balance setting at auto all the time. When you are uncertain about a proper white-balance setting, or when you come across a subject or scene with a complex color combination, you can always use RAW, then develop the image later the way you want it.
This method can be very risky with JPEG, particularly in terms of image quality, because you are changing the original colors of an already-developed image. Remember this as one of RAW’s important advantages.
As I explained last month, one of the biggest differences between the irreversible-compression JPEG format and the reversible-compression RAW format is the file space required for each image.
Let’s look at RAW’s usefulness in more concrete terms. By the way, the figures used here are the average of the manufacturer-provided specifications: the actual number of recordable images may differ depending on the type of image you take.
When you select an image size of 10 megapixels and use a 1GB recording media in the K10D, you should be able to capture approximately 202 images at Best (or lowest-compression) image quality of the JPEG format. If you switch the recording format to RAW under the same conditions, you can only take 59 images. In other words, RAW demands 3.5 times more file space than JPEG.
This tells you that, in terms of the number of recordable images, it’s impractical to choose RAW for all images in day-to-day shooting.
The following setbacks are very much related to the issues regarding RAW’s large file-space demands, as described in Point 3. RAW-format shooting means delayed camera response and slower data-processing/transmission speeds, simply because RAW files are bigger. This problem becomes more evident in consecutive shooting.
Based on the average of the manufacturer-provided specifications, you should be able to keep shooting images until the recording media runs out of storage space — a process known as “stream shooting” — when you set the K10D to the 10-megapixel image size and Best (lowest-compression) image quality of the JPEG format.
In RAW-format stream shooting, you should be able to capture approximately nine images in succession. This suggests that RAW is not suitable for consecutive-shooting applications involving moving subjects, such as fashion shows and sports events.
Because of its large data volume, RAW also requires a high-capacity personal computer to improve the speed and efficiency of post-shooting processes, including data transmission and photo retouching. In addition, greater filing space is required to store the final image data. Considering all these factors, you must be fairly well prepared to comfortably use RAW.
When you want to take RAW-format images all the time, set the camera’s recording format to either RAW or RAW+ (simultaneous recording of RAW and JPEG images).
The K10D also offers the convenient RAW button, which allows you to instantly switch the recording format to RAW+ during JPEG-format shooting. This means that you can use JPEG in ordinary shooting, then switch to RAW via simple pushbutton operation whenever you need it.
Via a custom function, you can assign one of two functions to this RAW button: either reset to the original recording format after a single exposure, or maintain the RAW+ setting until the playback button is pushed.
With the K10D, you can also select the DNG (Digital Negative) file format, in addition to the conventional PEF (PENTAX RAW) format.
DNG is a new, multipurpose RAW-data file format advocated by Adobe System, who is widely known as the manufacturer of the popular Photoshop retouching software. This publicly available archival format makes it possible to develop RAW-data files using any compatible RAW-data development software.
How to select RAW as the standard recording format
The following procedure should be followed when selecting RAW as the camera’s standard recording format. I recommend, however, that you choose JPEG as the standard format and use the RAW button when you wish to preserve RAW-format images.
Step 1: Step 2:
After pressing the MENU button to recall the rec. mode menu on the LCD monitor, use the up/down keys of the four-way controller to select the recording format listing. After pressing the right key of the four-way controller to display the set of recording formats, use the up/down keys of the four-way controller to select the desired recording format. Then press the OK button to confirm your selection. Finally, press the MENU button again to complete the procedure.
How to select a RAW-data file format (PEF or DNG)
Step 1: Step 2:
After pressing the MENU button to recall the rec. mode menu on the LCD monitor, use the up/down keys of the four-way controller to select the RAW-data file format listing. After pressing the right key of the four-way controller to display the two RAW-data file formats, use the up/down keys of the four-way controller to select the preferred format. Then press the OK button to confirm your selection. Finally, press the MENU button again to complete the procedure.
How to use the RAW button
Step 1: Step 2:
During JPEG-format shooting, press the RAW button to switch the recording mode to RAW+. This lets you simultaneously record both JPEG- and RAW-format images with the next shutter release. RAW+ is indicated on the LCD panel on the camera’s upper panel to confirm your recording-format switching. At the camera’s default setting, the standard recording format (JPEG) is restored after a single exposure.
How to assign a RAW button function
You can choose a desired RAW button function: either reset to the standard recording format after a single exposure, or to maintain the RAW+ format indefinitely until the playback button is pushed.
Step 1: Step 2:
After pressing the MENU button to recall the menu on the LCD monitor, use the right/left keys of the four-way controller to display the custom setting menu. Then, use the up/down keys or the front electronic dial to move to a custom setting page with a RAW-button function listing. Use the up/down keys of the four-way controller to highlight the one-touch RAW+ listing on the selected page.
Step 3:
After pressing the right key of the four-way controller to display two one-touch RAW+ functions, use the up/down keys of the four-way controller to select a preferred one between one time and continuous. Then press the OK button to confirm your selection. Finally, press the MENU button again to complete the procedure.
Over the last two months, we have studied both the benefits and disadvantages of the RAW recording format. If you have clear understanding of these, you know the right times to choose RAW:
When your priority is image quality;
When you want to retouch recorded images;
When you are uncertain about the proper white-balance setting;
Use JPEG for ordinary shooting, then switch to RAW using the RAW button when needed;
Choose RAW for subjects and scenes that require no consecutive shooting.
RAW-format special seminar: Part 3
Development process of RAW-format images
Now that you have learned the benefits of the RAW format, when to take advantage of this unique format and how to set the different RAW functions, it’s time to actually develop RAW-format images.
Which RAW suits you better — PEF or DNG?
I have mentioned two different RAW-data file formats: the original format (PEF, for PENTAX) and the Adobe System-advocated DNG format. It’s very understandable that DNG has attracted tremendous attention since its introduction, because it was developed and advocated by Adobe System, the developer and marketer of Photoshop — the de facto standard in the world of photo retouching software.
DNG provides an option to users of digital SLR cameras like the K10D, but I’m frequently asked about which format to choose. I usually answer that they should choose PEF — at least for the time being.
As a RAW-data file format, PEF files are processed with a certain degree of reversible compression, while DNG files are uncompressed. Because of this, I’m not convinced of the practical usefulness of DNG files at this point.
Secondly, most computer operating systems and software applications are designed to accommodate the original RAW-data file formats of major camera manufacturers. So I cannot come up with any particular reason to switch to a public, multipurpose format like DNG. Honestly speaking, even though a few years have passed since the introduction of DNG, it is not as popular as was originally expected, perhaps because of the issues I have mentioned.
Finally, in terms of visual expression, RAW-format images are not processed by the camera’s imaging engine — the key factor to reproducing the individual touches and renditions of each camera manufacturer. This means that RAW-format images lack brand originality. I suspect that, if you choose the DNG format and process DNG-format images with multipurpose data-processing software, you can no longer make a distinction among the different camera brands.
In this case, data-development software plays a very important role. Because I’m very fond of PENTAX’s visual presentation, I always use PENTAX PHOTO Laboratory, PENTAX’s original RAW-data processing software, to process RAW-format files.
Based on what I have described, I can’t find any particularly compelling reason to choose DNG as a RAW-data file format over a manufacturer-specific format like PEF.
Izumi Taniguchi's Profile
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Born in 1967 in Tokyo, Japan. Graduated in 1991 from Tokyo Polytechnic University. After working for an optical products manufacturer, he took up freelance photography in 1996. In addition to his professional assignments, mainly in the field of nature photography, he has also contributed articles on photographic techniques to a number of photo magazines, tutored at photo seminars, and served as a judge in numerous photo contests. His vast, in-depth knowledge covers all facets of photography, from the conventional film photography to the latest digital photography.
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Originally posted by Rusty 
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