# New patent app US20130258476A1 for EF35 F2 IS



## hpjfromdk (Oct 5, 2013)

On October 3rd, patent app. US20130258476A1 with priority in JP2012-072806 was issued
The US patent app entails 3 embodiments of a 35mm F2 lens with IS and a total lenght of 105mm (ref below). 
To achieve adequate reduction of comatic aberration with an aperture of F2 during image stabilization, the IS lens is placed adjacent to the aperture diaphragm. 
Emb Fl Fno ImH TotL BF 
1 34,49 2,05 21,64 104,5 38,3
2 34,49 2,02 21,64 104,24 37,58
3 34,5 2,05 21,64 104,5 38,3
4 34,47 2,05 21,64 104,5 38,3
Embodiments 1,3, and 4 have good correction for spherical, astigmatic magnification chromatic aberrations, but exhibit a negatively sloping curve i.e. some degree of barrel distortion 
Embodiment 2, is well corrected in terms of distortion but at the cost of lesser reduced levels of spherical, astigmatic magnification chromatic aberrations. 

Further details can be found here http://www.freepatentsonline.com/20130258476.pdf


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## candyman (Oct 5, 2013)

A 35-105 f/2 IS lens? That is interesting. Next to 24-70 f/2.8 MK II, 24-70 f/4 IS


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## neuroanatomist (Oct 5, 2013)

105mm is the 'total' optical length of the lens (physical length plus backfocus distance), not a 35-105 zoom. 

Odds are one of these designs was recently released as the new 35/2 IS. Since patents publish 18 months after they are filed, if company is moving rapidly they can get a product launched before the patent publishes.


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## Mt Spokane Photography (Oct 5, 2013)

neuroanatomist said:


> 105mm is the 'total' optical length of the lens (physical length plus backfocus distance), not a 35-105 zoom.
> 
> Odds are one of these designs was recently released as the new 35/2 IS. Since patents publish 18 months after they are filed, if company is moving rapidly they can get a product launched before the patent publishes.


I thought that Japanese patents are first released, then they are submitted for a US patent. Maybe that's wrong, but the Japanese patent may have been announced long ago?? It refers to a Japanese patent released in 2012, which I did not bother to look up, the OP should have done that.


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## hpjfromdk (Oct 5, 2013)

As stated US20130258476A1 takes priority in JP2012-072806
JP2012-072806 (hence) is the JP application number filed 2012-03-28
The application number for US20130258476A1 is US201313801467 filed 2013-03-13, i.e. before the 12 month deadline that allows it to take priority in the JP application. 
Adding 18 month to the JP filing date you get to 2013-09-28, but since US patent apps are published Thursdays, Oct 3'rd would be the closest you get to 18 month ... and if you look for it you will probaly find the Japanese "patent application laid open" will be published within a week or two...


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## candyman (Oct 5, 2013)

neuroanatomist said:


> 105mm is the 'total' optical length of the lens (physical length plus backfocus distance), not a 35-105 zoom.
> 
> ..................




Got it. Thanks


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