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Sony Alpha 900 or Equivalent

 
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Lens-Zero



Joined: 12 Jun 2011
Posts: 2

PostPosted: Sun Jun 12, 2011 9:01 pm    Post subject: Sony Alpha 900 or Equivalent Reply with quote

Since Bo-Ming you already have on hand the Contax-N electronic codes, can you do the same thing to Sony Alpha?

Or, for the sake of the majority Contax-N lens owners, can you develope an external device to control the focusing and aperture rings of Contax N, applicable to Canon EOS, or Sony Alpha, etc. who may take another step to alter ther bayonet mounts.
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conurus
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Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Tue Jun 14, 2011 1:13 am    Post subject: Reply with quote

1, we don't think a conversion from Contax N to Sony A-mount is possible, because the N-mount expects electronic commands to control the aperture, but the A-mount controls the aperture with a mechanical lever.

2, all Contax N lenses converted by us are capable of aperture control using the lens' own aperture ring without a Canon camera body. The only requirement is a power source for the lens. See this thread for details.

http://support.conurus.com/viewtopic.php?t=720

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Lens-Zero



Joined: 12 Jun 2011
Posts: 2

PostPosted: Tue Jun 14, 2011 2:58 am    Post subject: Reply with quote

conurus wrote:
1, we don't think a conversion from Contax N to Sony A-mount is possible, because the N-mount expects electronic commands to control the aperture, but the A-mount controls the aperture with a mechanical lever.

2, all Contax N lenses converted by us are capable of aperture control using the lens' own aperture ring without a Canon camera body. The only requirement is a power source for the lens. See this thread for details.

http://support.conurus.com/viewtopic.php?t=720


By suggesting an "external device" I meant something like a "ring flash" to wrap around the lens neck. I can see that there is something like 4mm between the aperture ring and flange ring, and there would be another 3.4mm (for Sony A) and 4.0mm for Canon EOS, enough thickness for a mini cell phone battery or lighter battery, or a number of button cells underneath. Thus letting the lens independant from the camera commands per se, on aperture and focusing. I will be very happy to see this to happer soon.
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ManWearPants



Joined: 18 Feb 2010
Posts: 74

PostPosted: Sun Mar 03, 2013 2:04 pm    Post subject: Reply with quote

Hi Bo-ming,

I came across this adapter that comes with aperture. Assuming you can put a chip that runs through this adapter to activate the in camera OIS and AF, would it be possible to relook into Contax N to Sony A-mount. This will be especially useful for 70-300 and 400mm. Assuming both ends are of Contax N female and Sony A male.

http://www.dgpal.com/static/images/products/productimage-picture-kipon-contax-645-lens-to-canon-eos-camera-body-adapter-contax645-eos-3887.jpg
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conurus
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Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Mon Mar 04, 2013 8:42 am    Post subject: Reply with quote

There is also significant overlap between ZA and Contax N. For instance, we have ZA 16-35/2.8, 24-70/2.8, 50/1.4 and 85/1.4. Sony A-mount users seem to be very well served by ZA, with AF, AE and sensor-based image stabilization. Lens conversions are costly so there is no chance Contax N will be able to compete with ZA lenses on Sony A-mount cameras.

Regarding lens adapters with auxiliary aperture diaphragms, I would like to point out that lens designers took great effort to decide where to put the aperture diaphragm. It cannot be placed arbitrarily anywhere without impacting optical performance. Some lenses were reported to work well with auxiliary aperture adapters such as the one you cited, but some other lenses had problems with vignetting or strange bokeh.

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