Teeth

A Meyer-Optik Gorlitz Orestegor 200mm f/4 Zebra lens on the front cover of an old 'She' magazine. Photographed with a Canon EOS 30D + EF 35-135mm f/4-5.6 lens.
The Meyer-Optik Gorlitz Orestegor 200mm, a sturdy East German pre set lens, was in production from 1963 until 1990. However, it was redesignated as a Pentacon following the merger of Meyer-Optik with Pentacon in 1971, when it was given auto diaphragm capability. At some point in the production run the number of iris blades was reduced from 15 to six, presumably as an economy measure. This occurred during the 'Pentacon' years. The original Orestegor with its 15 blades is known as the 'bokeh monster' because the blades form an almost perfect circle. Obviously that sort of geometry is impossible with only six blades in the diaphragm.