Asahi Optical Co. Super-Multi-Coated 35mm f/3.5-16.0

Lens categoryWide
Vendor nameAsahi Optical Co.
Type nameSuper-Multi-Coated
Product year1971
Focal min (mm)35
Focal max (mm)35
Focus min (cm)45
Aperture max3.5
Aperture min16
Element(s)5
Filter size (mm)49
Asahi Optical Co. Super-Multi-Coated 35mm f/3.5-16.0

Discontinued in 1979.

The rear grouping of elements in this lens contains a cemented doublet with a double convex and double concave lens. It is important to note cemented lenses in deconstruction, as splitting them will result in rough material on the glass. Recombining them as is will result in serious image degradation. The remnants of the glue can be removed with a solvent such as acetone. Typical materials for lens glue used by Pentax was Canada Balsam oil, due to its refractive index being very close to optical glass. In reparation one will need to find a suitable glue such as Cytoseal 280 among others, because if left alone, the separation of the elements will affect picture quality.

I have an example of this lens that has not yet been reglued, although it seems sharp still. (MaP)

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