Tōkyō Kōgaku lenses in Leica screw mount
Tokyo Kogaku, later renamed Topcon, made some lenses in 39mm Leica mount for some Japanese Leica copies, mainly the Leotax. All were all chrome unless noted. The chronological order is State - C Simlar - Simlar - Topcor - Topcor S.
- 35/2.8 Topcor, sold with a very big external finder
- 50/3.5 State (collapsible)
- 50/3.5 C Simlar (collapsible)
- 50/3.5 Simlar (collapsible)
- 50/3.5 Topcor (collapsible), diaphragm ring around the front lens, then around the barrel
- 50/3.5 Topcor K (rigid), aluminium barrel and knurled rings
- 50/2.8 Topcor, black and chrome finish
- 50/2 Topcor
- 50/2 Topcor S, chrome, then black and chrome, then black with aluminium barrel
- 50/1.8 Topcor S, black finish
- 50/1.5 Simlar
- 50/1.5 Topcor
- 90/3.5 Topcor, aluminium barrel and knurled rings, sold with an external finder
- 135/3.5 Topcor, aluminium barrel, sold with an external finder with 50/90/135 frames