Designed for full-frame mirrorless cameras, the 17mm and 50mm lenses are I-Series lenses featuring all-metal barrels. They are available in Sony E-Mount and Leica L-Mount. The 17mm is 1.9" long, weighs 8 ounces (L-Mount), and has a close-focus capability of about 4.7". The 50mm features an arc-type AF/MF switch and a stylized ring on the all-metal barrel.
The 23mm lens is designed for APS-C mirrorless systems and offers a 35mm field-of-view equivalency with the 1.5x crop factor applied. It is offered in Sony E-Mount, Leica L-Mount and Fujifilm X-Mount.
The Sigma 17mm F4 DG DN Contemporary lens lists for $599, the Sigma 50mm F2 DG DN Contemporary lens lists for $639, and the Sigma 23mm F1.4 DC DN Contemporary lens lists for $549.