7 TECHNOLOGIES:IMAGING CAPABILITY Expanding the Potential of Your Images

Proprietary X3F file format for outstanding texture and color

In fact, shooting in X3F format has some advantages. In a digital camera, the image signal captured in RGB is recorded by being converted into what is known as YCbCr color space. The Y stands for brightness, and the CbCr stands for color difference. In an ordinary digital camera, a file format known as YCbCr 4:2:2 is used, where the color signal is set to half the brightness signal. This format was developed in order to send color information efficiently on the limited bandwidth available back when color television was first developed. Designed on the principle that the human eye is less sensitive to color data than to brightness data, this historical format has survived intact to this day, and is still used as the mainstream format in digital cameras.

However, now that digital camera performance has improved so dramatically, people are using their photos in different ways, displaying enlargements on their computer screens, and large photo prints are mainstream. Today's output conditions are getting better and better. The old YCbCr 4:2:2 format was designed for efficient signal transmission, and not for high-quality output. To our way of thinking, this format no longer adequate to meet the needs of all photographers.

X3F images preserving the balance of the natural data

The JPEG files from the DP series are output in YCbCr 4:2:2 in compliance with the Exchangeable image file format (Exif) specification, which is the standard specification for file formats. But in the direct image sensor, each pixel location captures the full complement of RGB color data, so in X3F files, which is the RAW data format, brightness data and color data can be kept in a 1:1 ratio without relying on interpolation. When this image is processed in Sigma Photo Pro, even if it is saved as a JPEG, if the JPEG quality-setting selected is 7 to 12, it will be saved as YCbCr 4:4:4. The DP's image quality, with its amazing vividness and texture, is really due to the X3F image data, which preserves the balance of the natural data. For the best photos with the best image quality, we definitely recommend shooting in X3F mode.

JPEG mode: photos finished the Sigma way

JPEG images captured by the SIGMA DP are photos finished in what Sigma considers the most appropriate way. If you find that the photos you take in JPEG mode look the way you intended, then by all means enjoy the ease and convenience of the JPEG setting. Your JPEG images are ready to print - just plug the camera into your printer - and the image data files are ready to share with your friends and family. If you want email-friendly image files that can be transferred straight from your camera, JPEG mode wins hands-down on convenience.

However, when you create a JPEG file, the data is subjected to irreversible compression, which leaves very little scope for image-correction afterwards. And here's the rub: if you only shoot JPEG mode, you may find it very difficult to reproduce the photo you saw in your mind's eye, which is your own personal sensory experience. If you've ever used a conventional compact digital camera that only has JPEG mode, you'll know how unsatisfying the results can be. Unfortunately, it can be extremely difficult to fully express your artistic vision using only JPEG images, which are created using the camera’s automatic settings.

SIGMA DP2x Special Contents

Page Top