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Techart Pro - Firmware v4

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#1 JimmyD

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Posted 30 October 2016 - 03:57 PM

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​Just got my Techart adapter 2 days ago.  Downloaded version 4 of the firmware yesterday.  I was prepared for a letdown from high expectations, but it didn't happen.  I have only tried on two lenses so far--Leica 50mm Summicron and Zeiss ZM 85mm f/4--and I am more than pleased.  I am shocked at this technological marvel.  Shot at a lot of different apertures with both lenses yesterday, favoring wide open particularly when light wasn't great, and focus was very accurate. At least for focusing people, a much better hit rate than I would have had focusing manually.

 

To raise an old issue, not related to the Techart adapter but rather to adapting wide angle M out lenses on the Sony A7 series (i.e. the thick stack sensor issue), what 24mm, 28mm and 35mm M mount lenses have people mounted recently that have performed well?

 

Thanks!



#2 sophcat

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Posted 01 November 2016 - 11:56 AM

Best report I have found up to date
http://www.lensrentals.c om/blog/2016/07/guide-to-leica-wide-angle-lenses-on-sony-a7-series-bodies/
Just going to buy A7ii with the same adapter and studying the area too.)

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#3 JimmyD

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Posted 21 November 2016 - 06:08 AM

Thanks sophcat.  The Lensrentals report is very good if you typically shoot at close range, however, as one blog responder noted performance of rangefinder wide angles on Sony bodies gets worse as focus moves toward infinity.  This weekend I tested at infinity the Leica Elmarit-M 28m f2.8 II (one of the lenses which the Lensrental's report said the performance of was "useable wide open") with a novoflex adapter against the Nikon AI-s 28mm 2.8 with a Novoflex adapter and against the Sony GM 24-70mm f2.8.  The Leica was the worst of the bunch; at infinity it was nowhere near useable at 2.8; in fact, the corners were barely acceptable when stopped down to f11.  The Nikon had to be stopped down as well, but corners started looking okay at f8 and were better than the Leica's corners at f11.  At infinity at f11, the performance of the Leica was almost as good as that of the GM 24-70--with the Sony GM at 2.8 !!!



#4 Golem

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Posted 26 November 2016 - 08:30 PM

​.......... 

 

To raise an old issue, not related to the Techart adapter but rather

to adapting wide angle M out lenses on the Sony A7 series (i.e. the

thick stack sensor issue), what 24mm, 28mm and 35mm M mount

lenses have people mounted recently that have performed well?

 

Thanks!

  

I don't know why the M-mount-wides/thick-sensor question is 

endlessly reposted. A better question would be "What octane 

rating of gasoline is the best for drowning out fires ?" I myself 

just use the lowest, cuz it's cheaper and the result is identical 

to super high octane. 

 

You are soooo verrrry correct to be concerned about adapting 

non-retrofocus wide angles onto digital cameras. The image 

projection angles toward the off-center regions of the sensor 

are far more sensor-friendly with retrofocus lenses, because 

they are designed to provide clearance for the motion of the 

mirrors in SLRs. 



#5 Ben

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Posted 27 November 2016 - 07:53 AM

This thread's link

http://www.sonyalpha...y-mr-haruhikot/

outlines a method that may make previously unviable lenses an option for the Sony sensor stack. Plano convex auxiliary lenses can help. The problem is, that you need to calculate the proper parameters with a simulation of a similar optical design and then you still need to find a manufacturer that offers this very lens with the suitable thread diameter.

Although the Nikon 20/1.8 is a retro-focus uwa lens designed for slr registers it still suffers from strong field curvature, but I haven't been able to find a manufacturer that offers these kind of lenses in 77mm thread versions. I guess it comes down to luck, if this approach will work. Luckily the linked thread seems to be still active and it might yield some more working examples.

Hope this helps,

Ben


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