Egami spotted two new patents filed in Japan. The new patents include Tamron 90mm f/2.8 and the Sigma 180mm f/2.8 macro lenses.
It is not clear if both macro lens patents for the former Tamron SP 90mm F/2.8 Di MACRO 1:1 VC USD and Sigma APO MACRO 180mm F2.8 EX DG OS HSM lens. Both macro lenses employs a glass material.
Another filed patent shows that Tamron is also working on a 45mm f/2.8 Macro VC lens for Four Thirds cameras.
Tamron 90mm f/2.8 Macro Lens Details
Description and self-interpretation of the patent literature
- Patent Publication No. 2013-122559
- Publication date 2013.6.20
- Filing date 2011.12.12
- Related 2013-122558 The version without anti-vibration
- Example 1
- Magnification INF – X0.5 – X1.0
- Focal length f = 92.74 – 81.62 – 64.66mm
- Fno 2.89 -. 4.06 – 5.75
- Angle of view 2ω = 13.12 – 7.72 – 4.03 °
- Overall optical length 158.72mm
- 14 pieces in 11 groups Lens Construction
- Two XLD glass
- Tamron patents
- 6-group configuration of positive and negative positive negative positive
- (To the image side, and the fourth group and the third group is the object side is the second group) inner focus
- Shake correction (Group 5)
Sigma 180mm f/2.8 Macro Lens Details
Description and self-interpretation of the patent literature
- Patent Publication No. 2013-104994
- Publication date 2013.5.30
- Filing date 2011.11.14
- Example 1
- Magnification INF – 1:2 – 1:1
- Focal length f = 174.60 – 133.36 – 101.19mm
- Fno 2.91 -. 4.72 – 5.32
- Angle of view 2ω 14.07 – 5.23 – 1.98 °
- 19 pieces of 14-group lens configuration
- Three FLD glass
- Sigma patents
- 6-group configuration of positive and negative positive negative positive
- (Second set to the image side, the third lens group moves toward the object side) inner focus
- Shake correction (Group 5)
- Prevent enlarged by placing a group of smaller axial light beam, the anti-vibration unit
via EG
