This lens incorporates 4 FLD (“F” Low Dispersion) glass elements, which have performance equal to fluorite plus 1 SLD (Special Low Dispersion) glass element. It enables this lens to minimize the chromatic aberration, especially toward the telephoto end, and provide clear image quality with high color fidelity.
*FLD glass is the highest level low dispersion glass available with extremely high light transmission. This optical glass has a performance equal to fluorite glass which has a low refractive index and low dispersion compared to current optical glass. It also benefits from high anomalous dispersion. These characteristics give excellent correction for residual chromatic aberration (secondary spectrum) which cannot be corrected by ordinary optical glass and ensures high definition and high contrast images.