This would probably drive a professional editor up the wall, but for the target user, it’s brilliant. These cover 80% of the adjustments you might want to make, and the simplified tools do it better better than a novice messing with color levels or specific hue adjustments.
The sliders use the same radial brushed metal texture as the horizon adjustment line from earlier. We love it, but can’t help but feel like its use in the horizon line diminishes the power of this signifier. Across iOS 6, this texture means “knob for a slider.” But on that line, it’s just a button you can tap — you can’t drag it around.