16-18-21 MM BAYONET MOUNT LENSES

16-18-21 f/4 Tri-Elmar-M ASPH

The Leica 16-18-21 f/4 Tri-Elmar-M ASPH, introduced in 2006 at Photokina (see p.32 7/2006 Leica Fotografie International), was the second lens to feature a zoom design with three mechanical slots for fixed focal lengths, with the first being the Leica 28-35-50 f/4 Tri-Elmar-M ASPH lens³⁶¹. The lens was designed to work equally well on analog and digital M cameras²⁷⁷.

The lens employed a linear movement that simplified its design to some extent; however, the addition of internal focusing introduced mechanical complexity to an already intricate optical structure³⁶¹. Its compactness was achieved through an innovative method of attaching a separate filter holder and lens hood³⁶¹. This patented thread mechanism ensures that the hood and filter holder stop at a predetermined position, regardless of where you begin the movement, providing a secure lock and precise positioning similar to a bayonet mount³⁶¹.

The lens was resistant to flare, and shooting directly into the sun generated minimal ghosting effects³⁶¹. The lens was introduced during the production of the Leica M8 camera to offer users classic viewing angles at 21, 24, and 28 mm focal lengths³⁶¹.

The Leica 16-18-21 f/4 Tri-Elmar-M ASPH identified by the catalog number 11642³⁶¹. Its serial number started from 3995091³⁶¹. The lens consisted of 10 elements arranged in 6 groups, including two elements with aspherical surfaces³⁶¹. It offered an angle of view of 107º, 100º, and 92º, with a minimum focus distance of 50 cm³⁶¹. Weighing 335 grams, it included a filter holder in E67 size and a filter holder/adapter (14473)³⁶¹. This lens was available in a black anodized finish and featured 6-bit lens identification, along with a screw-on type lens hood³⁶¹.