Selecting a RAW File Converter

All serious photographers shoot RAW files when taking pictures they plan to edit and print. The reason is simple: RAW files give you greater adjustment flexibility, thereby allowing you to recreate the shot you saw and gain the best quality from your digital camera. However, before you can edit RAW files from your camera they must be converted into standard TIFF or JPEG format.

Because RAW file formats are proprietary, camera manufacturers must supply conversion software with all cameras that offer RAW capture. Unfortunately, that software can range from efficient to frustrating and it may only work with specific cameras from the manufacturer’s range. Older models may not be supported. For these reasons, many photographers seek out alternative RAW file converters.

In this feature we’ll look at the characteristics that make a third-party RAW file converter effective, and compare some of the leading products on offer. We’ve also listed some useful freeware applications you might like to try.

What to Look For in a RAW Converter

How can you decide whether a RAW converter is up to scratch? Here are some features you should consider:

1. Interpolation quality. Many different algorithms are used in the colour interpolation (‘Bayer de-mosaicing’) process that extracts the colour images from RAW files, and they can differ widely in quality and effectiveness. Check out how well detail is resolved (particularly in shadows) and whether noise is amplified when you try to extract more detail. RAW conversion always involves a trade-off between detail and noise, so you may need to sacrifice some detail to obtain maximum image clarity. In the end, be guided by what looks best to you. Experience will fine-tune your ability to be discriminating.

2. Camera profiles. A good RAW converter should come with effective generic camera profiles for all cameras supported. However, the most accurate profiles may not deliver pleasing results so, again, subjective evaluation may be required. Always check that the camera you use (or plan to buy) is included before purchasing the software. You may have to wait for the latest models to be included in some applications. Updated profiles are often offered free of charge.

3. White balance support. There are two kinds of white balance correction: one involves clicking on a neutral spot in the image, while the other uses presets and/or colour temperature to adjust image colours. Make sure you can preview white balance adjustments in real time so you can decide for yourself what changes to make. Some RAW converters provide a slider for adjusting tint/tone as well.

4. Exposure adjustments. Good exposure compensation is essential and you should be able to view the effects of adjustments on a histogram or equivalent display. Over-exposure is more difficult to counteract than under-exposure because when highlights are clipped you can’t restore the information that has been lost. Curves and Levels adjustments can be very advantageous.

5. Noise removal. Opinions vary as to whether it is better to remove image noise during RAW file processing or after the image is processed. Noise removal usually reduces overall image sharpness so some authorities say it should be applied early, so the problems are less likely to be amplified in subsequent processing steps. However, some very effective tools for high-ISO noise removal are available as Photoshop plug-ins, and you may prefer to use them. In that case, noise removal is optional in a RAW file converter.

6. Other adjustments. In most cases, removal of moirø© and adjustments to image sharpness, contrast, brightness and colour saturation and general colour corrections are best done in Photoshop, which supports a wider range of modifications.

7. User interface. Good RAW converters are simple to use and very interactive, performing most operations in real-time. A large preview is essential for checking adjustments. The ability to process adjusted files in the background while you work on the next image will improve workflow efficiency.

8. Colour management. Good RAW converters should also be compliant with colour management. Every file you get as output of the RAW converter should be tagged with a working space profile (choices of sRGB and Adobe RGB 1998 should be available at a minimum).

9. Batch processing. Many photographers have shoots in which all (or most of) the files require the same corrections. Being able to batch process such files can save you time and hassles. Most RAW converters support batch processing – but some limit the number of files you can process at a time.

10. Integration. A good RAW converter will integrate effectively with your workflow – and your favourite editing software. This integration should include a RAW file browser and the ability to apply settings from one image to a group of other images.

Click here for a comparison table (PDF) for third-party RAW converters.

[Above: Adobe’s Camera Raw is an integral part of the latest versions of Photoshop and Photoshop Elements and provides most of the controls serious photographers require. Regular updates ensure it is compatible with recently-released cameras.]

Freebies

The application that underlies most free (plus a lot of not-so-free) RAW converters is Dave Coffin’s dcRAW converter (www.cybercom.net/~dcoffin/dcRAW/), which is written in ANSI-C code and designed for use with Linux PCs. A list of applications that use dcRAW can be found on this website, along with cameras the decoder can be used with and some handy links to other software developers who have produced complementary programs that work with dcRAW, such as Windows and Mac compliers, Exif data viewers, and plug-ins for loading RAW files into editors, such as the Gimp.

Although this site has plenty to appeal to technophiles, photographers who are less interested in technology will probably want to go straight to applications that have been fully developed and tested. And there some excellent freeware programs to choose from with a range of different capabilities.

The latest version of Picasa (www.picasa.google.com) is one of the most polished and easy-to-use of the freeware converters. All versions of the popular graphic viewer, Irfanview (www.irfanview.com) from V3.92 on include RAW file conversion.

RAWDrop (www.wizards.de/RAWdrop/) is a software tool developed by Frank Siegert for converting RAW images from digital cameras to TIFF and *PSD formats easily just by drag-and-drop. RawView (www.through-the-lens.net) is a Java-based freeware application for batch conversion of RAW files to JPEG format.

However, our pick-of-the-bunch is Pixmantec’s RawShooter Essentials 2005, which provides most of the functionality serious photographers need. Available from www.pixmantec.com, it contains a powerful file browser, dynamic previews and multi-threaded batch processing support. It is also kept up-to-date when new cameras are released.

[Above: Pixmantec’s RawShooter Essentials 2005 is the most versatile and feature-rich freeware application currently available.]