Rodenstock Imagon

The Rodenstock Imagon is an achromat doublet photographic lens design uncorrected for spherical aberration used together with diffusion discs ("sink strainers") called sieve aperture (Siebblende [de] in German).

In a joint effort with the pioneering photographer Heinrich Kühn, who, as a pictorialist, was artistically seeking for "romantic softness without sugariness, blurring without a woolly effect"[1] in images and had been experimenting with binocular lenses and soft filters and rasters in the 1920s already,[1] the lens was technically designed by Franz Staeble [de],[1][2] founder of the optical company Staeble-Werk [de] in Munich, Germany.

The unusual term Tiefenbildner is a German composition, which can be best translated as "depth-of-field creator, modulator or painter" in an artistic sense; this designation was later dropped.

There are also variants which can be mounted on focusing helicoids or bellows to be used with medium format or 35 mm cameras.

By rotating the outer rim of the disc, the opening of these smaller holes can be modified, and by this the amount of softness, which superimposes the sharper core of the image, is also changed.