UV-Sonnar 105mm f/4.3

The UV-Sonnar is the one lens in the Hasselblad V system that is not made of glass. Optical glass absorbs ultraviolet, and so do the balsams and cements that hold conventional lens groups together, so Zeiss built this one from quartz and fluorite with seven elements standing in seven separate groups — every surface an air-glass surface, nothing cemented. Ernst Wildi’s Hasselblad Manual gives the payoff in numbers: ordinary camera lenses transmit down to roughly 350 nm, the quartz UV-Sonnar to about 215 nm. Zeiss’s data sheet adds the property that makes it usable rather than merely transparent — the chromatic correction covers the ultraviolet and the visible together, so “for UV photographs, focusing can be made with visible light without any further adjustment”, which spares the operator the refocusing dance that UV work otherwise requires.

The specification is otherwise modest and slightly awkward, as scientific optics tend to be. Seven elements in seven groups, an exact focal length of 107.2 mm despite the 105 mm name, a maximum aperture of f/4.3 that appears nowhere else in the system, an aperture scale running 4.3 – 5.6 – 8 – 11 – 16 – 22 – 32, closest focus of 1.8 m — twice the 100mm Planar’s — and 670 g in the C barrel with a Compur size 0 shutter and bayonet-50 filter mount. Because glass absorbs UV, the usual close-up accessories are unusable: Wildi instructs the reader to skip Proxars entirely and use extension tubes or the bellows, and notes that each lens came with a Schott UG11 filter in a bayonet mount to cut visible light, with the Wratten 18A as an alternative. Zeiss’s own list of applications is unglamorous and specific — textiles, detection of printing forgeries, materials examination of all kinds — with one line that is not: the lens is “of special interest for extraterrestrial UV photography”.

Only two versions exist, and they are the same optics in different barrels. The C ran from the late 1960s; lens-db.com dates it to 1968 and filmphotograph.com to 1967, and this entry takes the earlier date while noting that neither Zeiss sheet nor Hasselblad Historical’s lens table carries a year. The CF followed the rest of the line into the Prontor barrel in 1982, gaining bayonet-60 filters and 150 g — at 820 g it is the heaviest short lens in the system — with catalogue number 10 42 09 and a place in Hasselblad’s brochures among the “CF Special-purpose lenses” beside the Makro-Planars. There is no CFi, no CFE and no shutterless F version; Hasselblad Historical’s table lists the UV-Sonnar in C and CF and nothing else.

The prices are the clearest measure of what the lens was. Victor Hasselblad Inc.’s April 1973 suggested-retail list has “105mm UV-Sonnar f/4.3/black” at $3,627.00 when the 100mm Planar cost $715.00 and the standard 80mm $427.50. By the dealer list effective 1 January 1980 it had reached $6,350.00 — more than four times the 100mm Planar, more than the 500 C/M body with lens and magazine, and the highest figure anywhere on that price list. It is also, on that page, the single C lens written without a T*: every other entry in the block carries the multicoating mark and this one does not, which fits a lens whose whole purpose would be defeated by a coating tuned for visible light. What coating, if any, its surfaces do carry is not stated by any source consulted.

How many were built is unsettled. Leitz Photographica Auction, selling serial 7139689 from what it calls “the last batch of 20 lenses (7139688-7139707)” issued in 1988, states a “total production 73 lenses for Hasselblad C”; a member of UltravioletPhotography reports that when he approached Zeiss about his own, “they mentioned there were about 400 that they knew of”. The two need not contradict each other if the larger number counts every UV-Sonnar Zeiss made and the smaller only the Hasselblad C mount, but no source says so. What the auction lot does establish is that a C-shuttered UV-Sonnar was still being assembled in 1988, six years after the CF barrel replaced the Synchro-Compur everywhere else — evidence that the lens was made in occasional small batches to order rather than run continuously. Prices since have been erratic: $40,000 and $21,500 asked in 2019, about €15,000 in 2021, an estimate of €16,000–18,000 unsold from an €8,000 start at Leitz, and a $30,000 CF listing that Erin Emery’s lens guide mentions and then refuses to discuss further.

Open: the introduction year, 1967 or 1968; the true production total and how the 73 and 400 figures relate; whether the C version has serial batches between the reported first series (5139568–5139592) and the 1988 final twenty, and what the first series’ date was; whether any coating is applied to the quartz and fluorite surfaces; the aperture-blade count, which appears only in a forum specification list as five; when the CF was discontinued; and whether Nordin’s compendia carry a factory figure. No written review of the lens has been found — the only assessment traced is a forum remark that it is not as sharp as the UV-Rayfact and UV-Nikkor built for the same work.