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It’s coming, really!
We posted the filed patent of a 24-70 f/2.8L II way back in October. However it has now been published as of April 21, 2011. The big omission appears to be IS. I think it’s safe to say the lens is coming soon.
Other Lenses in the Patent
A couple of other lenses appear in the patent. A 70-300 f/4-5.6L IS, which has been released. Also appearing is a 55-250 IS lens. This could be a version II of the current lens. It could also shrink to 200mm at the long end.
- Patent Publication No. 2011-81062
- Published 2011.4.21
- Filled 2009.10.5
24-70 f/2.8L II
- Focal distance f=24.74 – 67.50mm
- Fno 2.92 – 2.91
- Half angle of view 41.17 – 17.77 deg.
- Lens length 206.42 – 177.53mm
- Back focus 38.43mm
- Aspherical 2
- zoom ratio 2.73x
- MOD 0.38m
70-300 f/4-5.6L IS
- Focal distance f=72.21 – 299.52mm
- Fno 4.65 – 5.85
- Half angle of view 16.68 – 4.13 deg.
- Lens length 142.64 – 201.84mm
- Back focus 37.77mm
- Aspherical 1
- zoom ratio 4.15x
- MOD 1.4m
55-250 f/4-5.6 IS
- Focal distance f=55.60 – 203.11mm
- Fno 4.16 – 5.88
- Half angle of view 13.80 – 3.85 deg.
- Lens length 162.05 – 202.41mm
- Back focus 58.79 – 82.03mm
- Aspherical 0
- zoom ratio 3.65x
- MOD 1.5m
Egami notes the 24-70 patent shows possible performance issues. You can check out their findings here.
The performance does not seem to be so good. The spherical aberration is delivered to less than +-0.2mm in all conditions at the outskirts. The astigmatism exceeds 1mm extremely badly in the short distance. The distortion is -4% of barrels type in the wide side. In the short distance, the distortion is +5% of lozenge type in the tele side. The chromatic aberration of magnification is corrected well.