Twenty Years of 28mm Ultron

Ultron is either a name of a certain design of Doube-Gauss-type lenses, or (mostly used as) a traditional name for a Voigtländer lens of f/2.0 or slightly faster - but not as fast as f/1.5 (then it's a Nokton).



A 28mm F1.9 rangefinder type wideangle lens in Leica Thread Mount (M39) under the brand name Voigtländer was presented at Photokina 2000 (Cologne) by Cosina. Sales begin was April 2001. It was a modern 9 elements/ 7 groups design. At that time it was the fastest 28mmm rangefinder lens in the world! (and still the fastest ever produced in LTM)

There was no Voigtländer RF camera with a 28mm frame at that time. This lens was set to market against LEICA's (then new as well) Summicron-M ASPH. 28/2.0 which was presented on the same Photokina. It can be imagined that Leica Sales people were a bit indignant about it. Although the Leica lens was shorter in size and probably a tad sharper, the price of the shiny Ultron 28/1.9 was merely 

a fifth of the amount Leica charged, and included a solid metal hood and nice slip-on cap, but not an external viewfinder (as came as a standard with their 25/4 15/4.5 uncoupled lenses)


Three generations of Voigtländer 28mm Ultrons: From left to right: Voigtländer Ultron 28mm F1.9 Aspherical (2001-2007, available in chrome or black) LTM (shown with M-adapter),

The first and second versions have sun shades included, but both are taken-off here for better size comparison of the pure lenses. The hood of the second (middle) is tiny and small. The actual version has no hood included (and probably don't need one in most situations). What annoys me is the large shiny outer bayonet (vintage Zeiss-Ikon-style) which is useless and a source of  glare with no hood. It would be much better if Voigtländer added a bayonet style front cap for it (as Zeiss did in the Contarex/Icarex era) instead of the cheap, shaky, prone-to-get-lost, big plastic front caps. The return of the nice felt-padded slip-on metal caps of the 1999/2000's to some lenses introduced since 2022 is a step in the right direction.

When comparing the front lens diameter of that three lens one can imagine the price of compactness (as well as to-the-edge-sharpness) of the newer designs, even the most expensive ones: Light falloff to the corners up to f/4 at least! Another optical aberration which gets more common on small compact wide-angle-lenses is distortion! It is common said that both aberrations can be corrected digitally, but this is true only to a certain extend: Waived distortion can't be corrected, and vignetting only at the cost of color contrast. At least in the aspect of distortion the Ultrons are unremarkable.

The back look shows that the rear lens protudes less backward with each version. Backward protruding rear elements and thus oblique impacting light rays are a serious problem for most, if not all digital sensors. But the 2008' F2 Ultron already behaves quite good on a (i.e.) Leica M240, no ugly color-shifts to the edges. The compact actual version is even less recessed and works even better. Note also the RF cam of the actual version is quite flat and acts as a shield to avoid sensor pollution with tiny drops of lubrication grease, which is a main reason why digital sensors need to be cleaned more often when M- or LTM-lenses are used on them.

Evolution of optical design: from large to compact. The actual design approaches the initial one.

LEICA  Summicron-M ASPH. 28/2.0 (2000-2015) and Voigtländer Ultron Aspherical 28mm F1.9 (2000-2007)
Picture of Ken Rockwell and link to his review


The LEICA 28mm f/2.0 was a (new at that time) biconcave-design and LEICA's first 28mm rangefinder lens of that speed.
So Cosina/Voigtländer weren't that bad!