The image circle was designed to match the size of the image sensors of most digital SLR cameras and this has resulted in a compact lightweight lens. The use of aspherical lenses provides correction for various aberrations and makes high quality images a reality throughout the entire zoom range. Compact dimensions offer superb handling and mobility.Digital characteristics were considered when designing the lens power layout. That's why the lens is the most suitable to make high quality images a reality throughout the entire zoom range. The coating for digital products used cuts down flare and ghost caused by digital SLR cameras and produces the best color balance. more info