Tamron filed two new macro lens patents in Japan for APS-C cameras. These are Tamron 30mm f/2.8 Macro and Tamron 28mm f/2.5 Macro.
- Patent Publication No. 2014-21341
- Publication date 2014.2.3
- Filing date 2012.7.19
- Example 1
- Focal length f = 27.49mm
- Fno. 2.60
- Angle of view 2ω = 55.11 °
- β = Inf – 1.0
- 10 pieces of 8-group lens configuration
- Four 7 sided aspherical
- Example 3
- Focal length f = 29.98mm
- Fno. 2.88
- Angle of view 2ω = 50.69 °
- β = Inf – 1.0
- 10 pieces of 8-group lens configuration
- Four 7 sided aspherical
- Tamron patents
- Three-group structure of the positive and negative positive
- Inner focus
- Single lens of a portion of the second group
- AF speed diameter, so small and light
via: EG