This 135mm lens is the longest available focal-length of the Illumina S35 high-speed series. It is also the only lens with a T1.8 aperture. Most other lenses in the series that consists of a total of 7 focal-lengths ranging from 14mm up-to this 135mm have a T1.3 aperture. The only exception is the 14mm that has got a T1.8. The lenses are available with either a feet- or a meter focus-scale.