Picture Quality / Size Options (8.5)
The Rebel XTi's 10-megapixel sensor delivers a native pixel dimension of 3888 x 2592 pixels. It records JPEGs at two quality levels – Fine and Normal - as well as RAW files. Its Large JPEGs are at full resolution, and Normal files are a bit more than half the size of Fine files. Medium size JPEGs are 2816 x 1880 pixels, and can be shot Normal or Fine. Small JPEGs are 1936 x 1288 pixels, and can be shot at Normal or Fine. RAW files are shot only at full resolution. The Rebel XTi can be set to record RAW and Large-Fine JPEGs simultaneously.
Picture Effects Mode (9.0)
Picture Style is a Canon initiative to make the look of their images consistent from camera model to model, and to create grouped combinations of image parameters for various types of shooting. The Rebel XTi has the same styles that more expensive Canon DSLRs have: Standard, Portrait, Landscape, Neutral, Faithful, and Monochrome. The user can tweak these for Sharpness, Contrast, Saturation and Color Tone, and can create custom styles using the same parameters.
Standard boosts sharpness and saturation. Portrait sharpens less and saturates less overall, but warms skin tones selectively. Landscape boosts sharpness and saturation, and selectively boosts blues and greens. Neutral doesn't sharpen or increase saturation, and is meant for users who plan to edit their images on a computer. Faithful is similar, but it's calibrated to match the subject when shooting in 5200K lighting.
Standard, Portrait and Landscape styles are meant for users who don't post-process their images. The styles are supposed to make post-processing unnecessary. They also make post-processing of JPEGs problematic – they boost saturation and sharpness, which decreases the amount of detail in the image. Sharpening a JPEG twice tends to create blotchy artifacts. Adjusting color twice causes similar problems.
RAW files show the effects of picture styles, but in a way that prevents data loss. Of course, with a RAW file, post-processing can accomplish everything that the styles can with much more flexibility.
