Sigma Photo Pro contd.

Sharpness (+/- 2.0 in 0.1 steps)

SD9 images are by default quite sharp but the sharpness adjustment can be useful for 'pulling out' subtle detail. I found a sharpness adjustment of +0.2 or +0.3 provided the best compromise between sharpness and sharpening artifacts. Photo Pro's sharpening algorithm appears to be similar to an unsharp mask. The images below are 100% crops from the same image at different sharpness settings.

Sharpness -2.0

Sharpness -1.0

Sharpness -0.5

Sharpness 0.0

Sharpness +0.5

Sharpness +1.0

Sharpness +2.0

Color Adjustment

Photo Pro's 'Color Adjustment' is carried out in one of two ways. Firstly you can enable the eyedropper function and simply click on a grey or white area of the image, color balance will be measured from that point and represented as a combination of Cyan, Magenta and Yellow. Alternatively you can simply drag the zero point around the color adjustment wheel manually, the changes applied in real time to the review image.

Color adjustment is useful for fine tuning white balance accuracy or compensating for strong light sources. It can also be used for special effects.

Adjustment 0	Adjustment 3M+6Y (white click)	Adjustment 5M+5Y (manual)

Save as: Image sizes

Photo Pro allows you to output the image in three different image sizes: same size, half size, double size. This means that you can output a standard 2268 x 1512 image as double size 4536 x 3024. You can also produce half size images which may be useful for web publication or color / tone proofing. Using the double size option from Photo Pro tended to produced slightly better images (less artifacts) than simply upsampling in Photoshop.

Half size (1134 x 756) - 343 KB JPEG

Same size (2268 x 1512) - 1,463 KB JPEG

Double size (4536 x 3024) - 3,972 KB JPEG

Save as: Color space

Photo Pro allows you to save the output image into a variety of color spaces: sRGB, Adobe RGB, Apple RGB, ColorMatch RGB. Saved files have embedded profiles, this means that when opened in an ICC aware application such as Adobe Photoshop they will be automatically recognized as being in a different color space (depending on your settings). Below you will find an sRGB and Adobe RGB sample of the same X3F RAW source, note that to view the color of the Adobe RGB image correctly you will need to download it and open it in an ICC aware application.

sRGB color space	Adobe RGB color space

Sigma Photo Pro: Performance

Timings below taken on a Windows XP workstation with a dual Athlon 1.2 Mhz CPU's and 1 GB of RAM. As you can see from the figures below Photo Pro caches a certain amount of its processing, this means that if you have opened (saved from browser or reviewed) an image in that session then any further review / save of that image will be extremely fast. Photo Pro is clearly designed with performance in mind and never really leaves you waiting (take note major manufacturers!)

Sigma Photo Pro: What's missing, Issues

This is the first release of Photo Pro (v1.0 Release 1024) and unfortunately it's not without a few issues. Luckily for Sigma and Foveon I should imagine it would be just a matter of time before some or all of these are addressed and a new version of Photo Pro made available, we will of course update this review at that time.

What's missing

• Ability to change white balance in batch (from the browser)
• Ability to assign / remember adjustments on a per image basis (or assign from browser)
• Folder creation / deletion
• Workflow management (grouping images / 'film rolls' / jobs)
• Printing directly from Photo Pro
• Chromatic aberration reduction
• Studio remote capture, the ability to capture / convert on the fly via Firewire / USB
• Noise reduction for higher ISO images

Current issues

• JPEG output quality (2x2 subsampling) lets down high quality source images
• Gray halos around overexposed areas of color (see below)
• Occasional slow response from browser

Color clipping / Gray halos

As highlights on colored areas of an image approach overexposure (presumably when a particular channel reaches saturation) Photo Pro can't work out the correct color for a pixel and instead turns it grey. This approach while scientifically sound produces images which have a unnatural look and fairly noticeable halos around highlights. These can be seen in the 200% magnified crops below.