The PORTRAIT HELIAR 75mm F1.8 is a large-aperture manual focus medium telephoto lens, exclusive to Nikon Z-mount, and the first Voigtländer full-frame interchangeable lens to incorporate a spherical aberration control mechanism. It covers the full-frame image circle, with an optical design optimized for the image sensors Canon mirrorless cameras.
This lens focuses on the relationship between spherical aberration and bokeh, enabling the deliberate control of under-correction and over-correction states to produce diverse bokeh expressions. Despite its Heliar-type construction with 6 elements in 3 groups, it achieves a large maximum aperture of F1.8. While changes in spherical aberration occur with aperture adjustment, operating the new control ring allows enjoyment of bokeh rendering with unprecedented variation.
Images with under-correction exhibit a soft-focus on the focal point and flare in highlights, while the background bokeh becomes smooth. Conversely, images with over-correction retain the sharp focal point, resulting in a hard, bubble-like bokeh. While these tendencies have traditionally been viewed as flaws requiring correction from an ideal optical design
perspective, this lens was planned and designed specifically to harness these characteristics for unique photographic expression. While varying spherical aberration optically shifts the focus position, this lens addresses this challenge with a mechanism that changes the spacing between lens elements in tandem with the control ring to counteract the shift. A small finger point protrusion is placed where the left thumb naturally rests during control ring operation, allowing the approximate correction state to be sensed tactilely. This lens incorporates electronic contacts, reflecting lens usage in the Exif data of captured images. It also supports in-body image stabilization and focus assist functions. The minimum focusing distance is 0.7m, and focusing is manual focus only.
The focus ring's metal finish features straight knurled pattern for the Nikon Z mount. A key feature is the high-precision metal helicoid, greased for a silky smooth operation, capable of withstanding precise focusing even at wide-open apertures. The aperture is mechanically controlled via a ring directly connected to the lens, adjusted on the lens itself rather than via the camera's command dial. The aperture consists of 9 blades, rendering out-of-focus point light sources with a pleasing, well-defined appearance.
