Cosina/Voigtlander Heliar 50mm f/2, nickel ltm version of 2009, 600 made. Certainly obscure, so under the radar, and our host might still have a few... 🙂
Compared with the earlier 50/2, this one is screw mount, rigid/not collapsible, with an infinity-lock focus tab. Same 11 aperture blades, and lighter in weight at 191gr. The first nickel-plated LTM lenses since about 1938.
Herbert Keppler's column in the Dec 2006 PopPhoto praises the previous model: "The Heliar turned out to be incredibly good, comparable at all apertures to the 50mm f/2 Leica Summicron-M we'd tested in 1996." Cosina did it with "Newly developed super high-index glass (that) reduces all aberrations." This is quite a breakthrough, as the Heliar was historically not suited to small-format use, its qualities not including the necessary acutance or desired speed. As essentially a Tessar with another element cemented-in to make a front doublet, it's amazing it could exceed f/2.8. Fastest Heliar ever made. Having only 6 air-to-glass surfaces, it's extremely flare resistant and contrasty.
Positive/Negative Negative Negative/Positive 5-element sequence with cemented pairs front & rear and a free-standing negative at center next to the diaphragm. This in contrast to the symmetrical classic Planar with Positive element at front, then a Pos/Neg cemented pair, mirrored behind the diaphragm. Like the Planar, the symmetry helps close-up sharpness, and macro lenses often use this pattern.
The optics are the same as the previous collapsible M-mount model, so this should still apply: Sean Reid says that it is softer wide open, esp in the corners (likely due to field curvature), than either the Summicron or Planar, and more subject to veiling flare for a "classic" rendition. Improved noticeably at f/2.4, but evidence of a focus shift at mid apertures.
My observation: Focus about right-on wide open and I suspect a slightly concave field of focus. Not crisp wide open but pretty good at f/2.8 and up. Maybe a slight tendency to front-focus a bit at f/4. Lovely smooth bokeh with very slight doubling in near-bokeh so perhaps undercorrected spherical aberration.
Compared with the earlier 50/2, this one is screw mount, rigid/not collapsible, with an infinity-lock focus tab. Same 11 aperture blades, and lighter in weight at 191gr. The first nickel-plated LTM lenses since about 1938.
Herbert Keppler's column in the Dec 2006 PopPhoto praises the previous model: "The Heliar turned out to be incredibly good, comparable at all apertures to the 50mm f/2 Leica Summicron-M we'd tested in 1996." Cosina did it with "Newly developed super high-index glass (that) reduces all aberrations." This is quite a breakthrough, as the Heliar was historically not suited to small-format use, its qualities not including the necessary acutance or desired speed. As essentially a Tessar with another element cemented-in to make a front doublet, it's amazing it could exceed f/2.8. Fastest Heliar ever made. Having only 6 air-to-glass surfaces, it's extremely flare resistant and contrasty.
Positive/Negative Negative Negative/Positive 5-element sequence with cemented pairs front & rear and a free-standing negative at center next to the diaphragm. This in contrast to the symmetrical classic Planar with Positive element at front, then a Pos/Neg cemented pair, mirrored behind the diaphragm. Like the Planar, the symmetry helps close-up sharpness, and macro lenses often use this pattern.
The optics are the same as the previous collapsible M-mount model, so this should still apply: Sean Reid says that it is softer wide open, esp in the corners (likely due to field curvature), than either the Summicron or Planar, and more subject to veiling flare for a "classic" rendition. Improved noticeably at f/2.4, but evidence of a focus shift at mid apertures.
My observation: Focus about right-on wide open and I suspect a slightly concave field of focus. Not crisp wide open but pretty good at f/2.8 and up. Maybe a slight tendency to front-focus a bit at f/4. Lovely smooth bokeh with very slight doubling in near-bokeh so perhaps undercorrected spherical aberration.
