Lens Distance Setting

[joewehry]

In Leica technical data for any given lens, I often see in the "distance setting" area, a detail of "smallest object field" and "highest reproduction ratio."

Ex for the Summicron 35mm, the smallest object field is 419 x 627 mm and the highest reproduction ration is listed as 1:17.5

What does this information mean, and what application does it have when taking a photo or printing it?

[giordano]

Originally Posted by joewehry

In Leica technical data for any given lens, I often see in the "distance setting" area, a detail of "smallest object field" and "highest reproduction ratio."

Ex for the Summicron 35mm, the smallest object field is 419 x 627 mm and the highest reproduction ration is listed as 1:17.5

What does this information mean, and what application does it have when taking a photo or printing it?

Smallest object field is the field of view when the lens is focused at its closest distance (on a full-frame camera, not a "cropped" digital sensor).

Reproduction ratio is the ratio between the size of the actual object being photographed and the size of its image on the film or sensor (regardless of "crop factor"). Divide the 419x627 image area by 17.5 and you get (near enough) the 24x36 Leica film frame.