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Author Topic: Sony A900 Announced  (Read 34282 times)
ErikKaffehr
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« Reply #80 on: September 16, 2008, 12:23:14 PM »
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Hi,

These are from the swedish Foto tests. They regarded the 135/1.8 "Top Class" but not the the 85/1.4.

I have some issues with Foto tests, they measure MTF down to 60 lpmm but only present results for 20 lpmm for full format and 30 lpmm for APS-C. The reports are based on all mesurements.

What I can see from these measurements is that:

1) MTF on 85/1.4 is low on full aperture in absoulte terms, not compared with other lenses.

2) Both lenses have singnificant astigmatism, even at aperture 8. Astigmatism means that sagittal and tangential structures don't have the same plane of focus.

There are other parameters than MTF, for instance flare and ghosting.

Best regards
Erik


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Absolutely true. Exceptional results on 1.5x APS-C is no guarantee for high-performance on FF. In fact dpreview has 2 different results for APS-C and FF, for every lens they test but Photozone only tests with APS-C sensors.
Now that the Sony FF is here, all of these lenses will be put to the test, under the unblinking glare of a high pixel density FF sensor. We will see how the tire measures up, when the tread hits the road. Since all of these lenses are designed/developed in the digital age (as opposed to film-era designs), I doubt any of these will have any problems in out-resolving the requirements of these sensors, either at these or even higher resolutions. We will see.
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« Last Edit: September 16, 2008, 12:33:24 PM by ErikKaffehr » Logged

aaykay
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« Reply #81 on: September 16, 2008, 03:15:18 PM »
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2) The G-lenses which seems to be based on Minolta designs. Who is building them?

Just a clarification here.  Please note that Minolta/Konica-Minolta was a top notch lens designer/manufacturer and was second to nobody, in that business, including making their own optical glass.  Some of their designs, like the 135mm STF etc are classics, unmatched by anyone else till date.

Their "G" line of lenses (70-200 f/2.8G, 300mm f/2.8G, 600 f/4 APO G, 300 f/4 APO G, 400 f/4.5 APO G, 200 f/2.8 G  etc)  are  high-end lenses comparable to a Canon 'L' and the equivalent high-end Nikons.  

KM sold their entire photography assets, including camera factories, lens factories and the whole shebang to Sony, when they got out of the business.  Their entire Photography and optical design staff also moved en-masse into the Sony fold.  Their Alpha 900 design team itself included 200+ engineers, a signficant portion of whom moved in from the legacy Konica-Minolta organization.

Sony however, did pay some royalties on some patents that they did not purchase outright (I assume they don't intend to use those patents for too long).  Some of the patents were purchased by Sony out-right, which I assume was because they intended to use them long-term or develop them further.

So, if someone wants to know where Sony builds their high-end lenses in Japan, you won't have to seek too far....Sony has had the ability to build dSLR lenses in-house, for around 2 years.    The professional-grade Zeiss lenses may or may not be built at these Sony (legacy KM) plants (they have not published where exactly those are assembled), since they have to follow the Zeiss manufacturing standards and use Zeiss equipment for the manufacturing and also testing/QA and also have to house Zeiss staff for audit/QA.  

They probably get their consumer-grade lenses (and also the Tamron-rebranded-Sony APS-C lenses), sub-contracted out to Tamron.  Even the Sony designed 16-105 APS-C-only lens is also (probably) sub-contracted out to Tamron.
« Last Edit: September 16, 2008, 03:19:38 PM by aaykay » Logged
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