Radionar 38mm f/3.5

Notes and sources

Robot M26 screw-mount standard lens. A triplet (3 elements/3 groups) and an eight-blade iris are documented by the Burgard specimen review and the Collection-Appareils object record. Published specimen reports disagree on minimum aperture (f/16 versus f/22) and nearest focus (0.50m versus 0.55m); these two canonical fields are unset, without inventing separate production Versions from that discrepancy. The retained 140g weight is a specimen measurement; the 46mm diameter and 21-25mm flange-to-front length follow 135compact, not an overall-length specification. A screw-in collapsible hood is illustrated by Burgard. Exact filter-thread standard and production boundaries remain unverified.