Heliar-Hyper Wide 10mm f/5.6 Aspherical

The Heliar-Hyper Wide 10mm f/5.6 Aspherical was, when Cosina released it in 2016, the widest lens ever made for the 35mm full-frame format without bending the picture into a fisheye: 130° across the diagonal, thirteen elements in ten groups with aspherical surfaces doing the straightening. Cosina brought it out in 2016 as the widest of a new trio of M-mount ultra-wides — the 15mm f/4.5 III of March 2015 before it, the 12mm f/5.6 III that November after it — and it did so in two mounts at once — Sony E first, on 26 May 2016 at ¥155,000, and then this VM version on 21 July at ¥135,000 excluding tax. In the Leica-thread and M-mount Voigtländer line it sits below the 12mm f/5.6, which had held the widest-rectilinear title since 2000, and it is the first of the family with no ancestor: there was no 10mm in screw mount, and there is no earlier version to confuse it with. It is still in Cosina’s VM catalogue, and it remains the widest lens in any Leica-compatible mount; the only lens to go wider on full frame since, Laowa’s 9mm f/5.6, exists for mirrorless mounts only.

The specification is Cosina’s: f/5.6 to f/22 in half-stop clicks on ten blades, 0.5m minimum focus, a barrel 67.8mm across and 58.7mm long that weighs 312g, and a hood that is part of the barrel. There is no filter thread, and there is no rangefinder coupling — Cosina’s page says 距離計連動なし in as many words. On a film M or a Bessa the lens is scale-focused, which at 10mm is less a limitation than it sounds: the depth-of-field scale does the work, and the focus ring stops at half a metre. What the body cannot do is show the picture. No M-series finder frames anything wider than 28mm, so the lens needs the optional 10mm Viewfinder M, a ¥45,000 accessory that is not in the box, or a digital body with live view. The E-mount version of the same glass adds electronic contacts, a de-clickable aperture ring and a longer, heavier barrel — 68.5mm and 375g — and that is the version most reviewers tested.

The reviews agree on the optics and split on the mount. Bastian Kratzke, who tested the E lens for Phillip Reeve’s site and notes that the M version is optically identical, found good to very good sharpness and contrast in the centre and midframe from wide open, negligible distortion, excellent resistance to flare and coma, and sunstars he calls beautiful; against that, vignetting of about 2.5 stops in the far corners that stopping down never removes, corners soft at every aperture, and a faint green cast on an A7s. Jordan Steele at Admiring Light, also on Sony, came away convinced to buy one — a lens under three inches long, solid metal throughout, that does things no other lens can — with the warning that 10mm demands composing around the converging lines rather than against them. Louis Ferreira at Sony Addict is the one who shot both versions, the M lens on a Leica M240 and then adapted to a Sony A7, and his finding is the one a buyer needs: on the Leica the M lens is very sharp in the centre with the fall-off confined to the edges and distortion amazingly well corrected once the camera is level, but on a Sony sensor it shows colour problems he calls horrendous, which the E version cures with a built-in correction profile. His advice is to buy the mount the lens will actually live on.

What to check when buying is therefore mostly which lens it is. The VM version is the one with the Leica bayonet, the shorter barrel and no contacts; an E-mount lens on a listing headed “Leica M” is a mistake, and a VM lens bought for a Sony is the wrong choice. The 10mm Viewfinder M is a separate purchase and rarely comes along in the box, so a listing that includes one is worth more than it looks; a listing for the finder alone is not the lens. The front element sits behind a hood that cannot come off and takes no filter, so the front cap matters more than usual, and cleaning marks are the first thing to look for. Nothing about the mount couples to a rangefinder, so a seller describing the lens as coupled is describing the 12mm III or the 15mm III instead — those two are the 10mm’s stablemates, and the three barrels look alike from a distance.