By Wendell Benedetti and Ron Eggers
Over the last few years the raw file has become the de facto standard for high-end professional digital imaging. The raw capture provides a level of image control that just isn't available any other way. This feature takes a look at raw files and how Nikon Capture NX and Adobe Photoshop Camera Raw handle raw processing.
As Adobe underscored with its development of the DNG format, raw files can be equated to film negatives. All the information required for an image is there, it just has to be processed and optimized. The raw file converter compares to the role of darkroom developing.
The fundamental difference between RAW and all the other image file formats is that the camera that captures a raw image doesn't handle the digital processing required to optimize it.
Everything that would have been done by the camera's built-in optimization engines with other JPEG or TIFF formats has to been done in post processing on a computer. Until recently, working with raw file formats could be cumbersome. Each manufacturer had its own conversion software, and many times raw formats for different camera models from the same manufacturer weren't compatible. That meant that manufacturers had to ship proprietary raw converter software applications with each camera they sold.
The need for additional software for each body or model line was a pain, and if a photographer wound up on a computer system without his specific raw converter, he was out of luck altogether.
Programs like Raw Shooter and XnView provide some post processing and conversion capabilities for a variety of RAW file formats, but they don't include all the optimization features that maximized the image quality of raw files.
Adobe Lightroom 1.2 shares the same processing engine as Camera Raw, but not all of the functions. In Camera Raw, you can set 9 color picker samplers that provide readouts on RGB values and you can set the color space that drives the RGB values. Apple Aperture also has raw processing features, which were reviewed in the May issue of Professional Photographer.
Photoshop Camera Raw and the Adobe DNG file format addresses the consumer's need for extensive optimization control for a broad range of raw file formats while Nikon Capture NX does the same for Nikon's proprietary NEF file format.
Camera Raw 4.1 (now updated to 4.2*) is a Photoshop CS plug-in, and Capture NX is a stand-alone application. Both include a comprehensive selection of optimization tools that control things such white balance, exposure, brightness and contrast, as well as the levels and slider controls that tweak the shadow to highlight sections of an image. Both applications also include hue/saturation/luminescence sliders, and lens aberration correction.
Either application will get the job done quickly and neither's learning curve is too steep. Any photographer who's used a proprietary raw file converter will feel comfortable working with either application's interface. Nevertheless, it would wrong to equate Camera Raw or Capture NX with other raw conversion applications. They include a selection of special tools that set them apart from the competition, and from each other.
Several tools set the Camera Raw plug-in from other raw converters. Its four Sharpening sliders, for example, give users the ability to precisely adjust where and how sharpening applies. Of the four, the Amount slider defines the degree or strength of sharpening. It works like other percentage value sliders, but the scale goes from 0 to 150, instead of 0 to 100.
Image ©Wendell Benedetti
The Radius slider defines the distance from an edge in pixels that sharpening will affect, while the Masking slider adjusts the level of sharpening that takes place in sections of an image that don't have pronounced edges. The Details slider seems to work like other threshold sliders, yet it doesn't appear to introduce any noticeable JPEG-like artifacts, even when the slider is set to the maximum affect.
By carefully adjusting the four sharpening sliders, photographers can precisely define and apply a level of sharpening that's appropriate for each image. However, don't be surprised when the sharpening effect is not immediately evident on the image. Camera Raw doesn't update the on-screen image until the image zoom level has been set to 100 percent or greater.
The Clarity slider, another Camera Raw tool, adjusts mid-tone contrast without dramatically affecting the other parts of the image. It gives images a little something extra, something print-making darkroom technicians referred to as snap. With some effort, it's possible to come close to the Clarity affect by using a combination of other Camera Raw tools, but it can't be fully duplicated.
The Noise Reduction tool in Camera Raw uses Luminance and Color sliders to minimize the electronic noise that's associated with images captured at high ISO. Though not the equal of a dedicated noise removal plug-in that takes the digital camera's sensor characteristics into consideration, it does a good job of minimizing noise without seriously degrading detail.
Photoshop Camera Raw, which now also works with JPEG, TIFF and DNG files, supports more than 160 digital cameras that generate raw files. It ships with Photoshop CS3 and is available as a free download for Photoshop Elements users.
Nikon Capture NX software supports the company's proprietary NEF raw files, as well as JPEG and TIFF images. It doesn't work with DNG files. Capture NX's unique capabilities set it apart from other RAW conversion applications. Its Control Points use U Point technology developed by Nik Software to give photographers an entirely new way to immediately see the effect Control Point adjustments will have on user-defined areas of an image. Color Control Points modify hue, brightness, contrast, saturation, red, green, blue and warmth. Black, White and Neutral Control Points control dynamic range and color casts. Capture NX also has a Red-Eye Reduction control Point.
Image ©Ron Eggers
To visualize the effect, think of Control Points as real-time Photoshop Levels eyedroppers that can be placed and moved around on an image. As you move the eyedropper, the resulting effect is immediately reflected onscreen.
For example, selecting the Neutral control point and dragging it around an image shows how the image will appear when the color under the control point is considered to be neutral gray. While this may sound like a useless exercise, it opens up all kinds of interesting possibilities. All Control Points can be placed and moved around the screen at the same time. Although it takes a while to grasp what this utility can do, it's worth exploring.
The Capture NX Edit List on the far right side of the screen serves several purposes. When you first open an image, its Edit List is empty. Then, as you apply various NX tools to optimize the image, each tool shows up in the list as a numbered entry in the order of its usage. If you use Brightness/Contrast first, it's at the top of the list.
Image ©Ron Eggers
The Edit List also allows users to selectively turn the affects on or off, or re-adjust them. It's a powerful, sophisticated undo tool that keeps the original image intact while recording and storing all the changes made to it.
Nikon Capture NX is available for Mac and Windows systems and has a street price of $149.99.
If you're going to be working with a variety of RAW file formats captured by different camera models, go with Photoshop Camera Raw. But if you're working strictly with Nikon gear, Capture NX is the obvious choice.
*The Photoshop Camera Raw 4.2 update added support for additional camera models and corrected a bug that affected noise reduction for Bayer patterned sensors.