A RAW image file is quite different than TIFF or JPEG. RAW files contain the pure raw data as it comes from the CCD, typically 12-bits represent one pixel of the CCD array. No in-camera processing is applied to this data, this is left to conversion software used at a later date. In addition to the raw CCD data the header of a RAW file will also contain exposure and setting information such as selected white balance, tone, sharpening etc. all of these parameters are used by the raw conversion software to produce the final image.

RAW image files can be seen as a 'digital negative', they are untouched by the camera processing algorithms and are therefore open to improved image processing facilitated by the additional processing power of a desktop computer and ever improving processing algorithms. At the time of writing this review there are only two applications available for RAW conversion of S2 Pro RAW files, both from Fujifilm. It will be interesting to see if any third party companies produce RAW conversion software which can handle S2 Pro RAW files (especially considering the honeycomb SuperCCD layout).

S2 Pro RAW files have the .RAF file extension, interestingly they contain a 1440 x 960 JPEG which can be viewed by certain image viewers (works with ACDSee). This JPEG is no doubt used by the camera for playback and magnification. At the moment there is no facility to extract this JPEG but it would be useful, perhaps in a third party application.

RAW File Converter LE

RAW File Converter LE is a very simple application which provides straightforward conversion of RAW image files to a 4256 x 2848 8-bit TIFF (each one 35,591 KB) in the sRGB color space. There are no options or settings which can be applied. The white balance, sharpening, tone and color saturation settings made at the time of the exposure are used for the conversion. To use RAW File Converter LE simply drag and drop an image or group of images onto the application then click on 'Convert'.

RAW File Converter EX

RAW File Converter EX is the extended RAW converter from Fujifilm. It is part of the 'Hyper Utilities' suite which is an extra cost (£129.99 in the UK). Personally I feel that EX should be a standard part of the S2 Pro kit, Converter LE offers no control at all. EX offers no thumbnail browsing, multi file selection (although you can drag multiple files), no zoom or other 'normal' features.

Having used many different RAW conversion packages from different manufacturers I can say that I don't feel that RAW File Converter EX is worth the money, especially considering what you get for free from other manufacturers. The problem is that without Converter EX you don't have any useful RAW conversion options. Lets hope those third party converters turn up soon.

Converter EX allows you to select your output bit depth and color space at the time you drop an image or group of images onto the application. Note that you can only select Adobe RGB with a 16-bit TIFF output (each one 71,103 KB). Good news is that Fujifilm are correctly tagging these TIFF files with the Adobe RGB color space (Photoshop recognizes it). There is also a special Fujifilm RGB color space. sRGB color space output is available only with 8-bit TIFF files. There is no option to convert RAW files directly to JPEG.

The main window for Converter EX is split into two sections. On the left is a preview of the RAW image (as it will be at the time of output) along with the output image size (you can select any of the four standard image sizes). On the right are the custom settings options, leave 'Camera Setting' checked and Converter EX will simply convert the image according to the settings recorded in the RAW file at the time of exposure.

Check 'Custom setting' to alter various settings. You can choose a predefined tone curve or make your own, select a predefined white balance (which can be fine tuned), use a gray picker white balance or enter a color temperature white balance. You can define sharpness, color and sensitization (digital exposure compensation). These custom settings can then be saved into setting files to be used on batches of images later.

RAW Conversion Performance

The test machine used was a desktop PC with dual Athlon 1592 Mhz (1900+) CPU's 1 GB of RAM running Windows XP. Software used was RAW File Converter LE and EX. Five RAW images were run through the RAW conversion software, the time taken was then divided by five to calculate an approximate time taken per image.

Software Output image Color space Image adjustments Time taken per image
Converter LE 4256 x 2848 8-bit TIFF sRGB None 29.2 sec
Converter EX 4256 x 2848 16-bit TIFF Adobe RGB None 31.6 sec
Converter EX 4256 x 2848 8-bit TIFF sRGB None 30.2 sec
Converter EX 3024 x 2016 8-bit TIFF sRGB None 29.6 sec
Converter EX 4256 x 2848 8-bit TIFF sRGB Tone, WB, Color, Exp. 29.6 sec


The following tests were performed by taking the exact same scene first as JPEG and then as RAW. The RAW images were then converted to TIFF using Converter EX. These TIFF files were used for the crops you see below, however they are far too large to provide for download so high quality JPEG copies are the only option we can provide for your own comparison. Due to bandwidth constraints it is also not possible to provide the original .RAF files (which are in excess of 12 MB each).

Resolution chart

Below you will find crops from shots of our standard ISO resolution chart. First at the 4256 x 2848 (12 mp) resolution and then 3024 x 2016 (6.1 mp). As described above the JPEG's are straight from the camera, RAW files converted using Converter EX.

4256 x 2848 (12 mp) image size

JPEG (4,442 KB) RAW (as a 2,630 KB JPEG)

At the full 12 megapixel image size it's clear to see that the additional processing power (and time taken) to convert the RAW to TIFF has a positive effect on image quality and resolution. A S2 Pro RAW file converted at this resolution almost produces maximum resolution on our resolution chart (in both horizontal and vertical directions). There are also quite noticeably less moiré, jaggies and sharpening artifacts in the RAW converted image.

3024 x 2016 (6.1 mp) image size

JPEG (2,318 KB) RAW (as a 1,367 KB JPEG)

At the more manageable 6.1 megapixel resolution it's great to see that the RAW converted image exhibits so much resolution that once more it pushes our resolution chart to its limits. Without a doubt the RAW converted images exhibit the highest resolution we've seen from any six megapixel DSLR.