Rollei filter ident required, Du1o 1 - 34 diameter

[david_seto1]

I'd be grateful to anyone who can describe the function of this bay 2

filter. And possible value if I decide to sell it.

It is clear with fine concentric etched rings.

Thanks and regards David.

[victorm.]

Duto filters diffuse (soften) the image. "They produce fluffy, softened contours and sunny, halo-like highlights..." That's what "The Rollei Handbook" says. The effect seems to be one of a sharp image overlaid with a soft image. They work best at wide apertures, losing some of their effect as the lens is stopped down. Rollei supplied them in two strengths, 0 and 1.

[patric_dahl_n]

The name "Duto" comes from the inventors, the hungarian photographer Jenö Dulovits and Miklós Tóth (DuTo) who came up with this soft filter in the early 1930's.

 

The softening effect tends to differ with the aperture you use. They works best with the lens fully open to 5,6. Don't use it with smaller apertures than 8-11. If one use Rolleinars (close-up lenses), Duto and stop down to 22 the concentric rings could be visible on the negatives/transparents and on the prints.

[victorm.]

Thanks, Patric, for the additional information. It's all too easy to forget that someone had to have the creativity to invent what they needed rather than simply buying something.