## Hardware Design__Rating: 9/10__The industrial design is the perfect balance of functionality and elegance. There are no superfluous buttons or rings. In fact, there are no buttons at all. This is a fully manual lens which means that both the aperture and focus are set on the lens itself. However, __the rings controlling these settings can be easily operated as they are well separated from each other and have different widths__ (Unlike the Loxia models).This lens is the direct descendant of the original Super Wide Heliar by Voigtlander. It's is actually the third generation __specifically made to be used on Sony FE Mount camera bodies__. Previous versions, made for Leica, could always be adapted to be used on Sony A7 series cameras, but that introduced several issues: purple coloring towards the edges (due to the way the light would impact the sensor), larger _effective_ lens size (due to the adapter) and no exposure info being fed back to the camera. Since this is a fully Sony FE-Mount lens, EXIFinfo is passed to the camera for each shot. Additionally, the optical issues have been corrected (more on that later).This lens is __tremendously small__. It's just slightly larger than the Sony/Zeiss 35mm/f2.8 (http://amzn.to/1ORg8jR), which is my point of reference for small lenses on FE mount.I used to use a Rokinon 14mm f2.8 (http://amzn.to/1UejkFq) before switching to this lens and although they are both native Sony FE-Mount lenses, the difference in volume and weight is just ludicrous. Although the Rokinon is an "OK" lens from an optical point of view, it poses several disadvantages: it doesn't communicate with the camera in any way, so Exposure EXIF information is not embedded in images. Also, the Rokinon lens exhibits some serious distortion that needs to be corrected in post-production. Granted, the Rokinon 14mm is a _faster_ lens (i.e. f/2.8 vs f/4.5), but in this case, I rather sacrifice those few stops for excellent image quality, portability and building construction.The focus ring is fully mechanical, meaning that it has both _start_ and _stop_ points as opposed to the _focus by wire_ method used by modern auto-focus lenses where the focus ring turns freely in both directions. Mechanical focusing provides a better feedback and allows to achieve accurate focus easier and faster than focus by wire most of the time, in my opinionIt's worth mentioning that the camera can be set to activate the _focus magnifier_ as soon as the focus ring is operated, which is a feature that some people may find appealing. I prefer setting one of the camera's configurable buttons to do so, but that's just personal preference.One disadvantage of Voiglander's design, is the fact that the __lens hood is permanently attached__. That means that, no filters can be used on this lens.## Hardware Quality__Rating: 10/10__The Voigtlander 15mm f/4.5 is a little and hefty bundle of metal and glass. It feels as solid as the Sony/Zeiss 55mm/f1.8 (http://amzn.to/1Veynkx) or any Batis lens (http://amzn.to/2356hKb) released by Zeiss. This may not be a coincidence, as Cosina Japan manufactures several Zeiss lenses.Although the lens is relatively heavy, it doesn't make the Sony A7 II camera feel out of balance. The focusing ring moves smoothly, with just the right amount of friction. The aperture ring makes an audible and pleasant "click" when changing apertures. However, __it can be easily de-clicked to improve operation and handling when filming video__.## General Performance__Rating: 9/10__The lens' performance is extraordinary, in my humble opinion, and I'm not the only one out there praising it. There is a famous review for the first generation of this lens by Ken Rockwell and he puts it ahead of the Leica 21 mm f/2.8 (http://amzn.to/1THCmSm) and the Leica 18mm f/3.8 (http://amzn.to/1UpSEBs). Although the reviewed model was geared towards Leica Film cameras, this version has been optimized to work on digital cameras.### Sharpness / Corner testsI setup the camera on a tripod, disabled "Steady Shot" and took several shots of the scene below with different apertures (f/4.5, f/9.0 and f/22.0), always focusing on infinity. The attached images were edited just to slightly increase exposure, no other post-processing was performed. I have included images of corners and center of the frame as reference.The Voigtlander 15mm f/4.5 sharpness performance in both center and corners is outstanding. I keep checking the photos on camera (LCD screen), zooming in and having difficulty finding images that are not sharp, even without using a tripod. I'm not exaggerating, it's really impressive to say the least. Although sharpness tends to fall towards the ends (especially at f/4.5), image quality is still very good.### ContrastAlthough the lens doesn't have the outstanding color contrast performance of Zeiss lenses, it's pretty close to it!, and does not small achievement. Obviously, contrast can be tweaked in post-production via Lightroom.### VignettingThere is definitely vignetting, but that's just expected considering such a wide focus lens. It's worth mentioning however, that it's much controlled than the vignetting presented by previous Heliar generations. Additionally, __the purple tint on edges exhibited by previous generations has been controlled__. In any case, vignetting can easily be corrected by clicking a checkbox in Lightroom (see below).## Ease of Use__Rating: 10/10__The lens is as easy to use as any other manual focusing lens. Actually, I would say it's _easier_ to use. This is because due to its wide angle and small aperture (i.e. f/4.5), it's very likely it would be used for landscape and/or architecture photography, in which case just setting the focus ring to infinity would be enough to have everything crisp and focused most of the time.