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CZ Contax versus CZ Sony

picman

Member
I was surprised to see the difference in MTF charts between the 85mm1.4 in Contax/Yashica mount and the 85mm1.4 in A-mount (see attached files). There seems to be a considerable progress since the Contax days. Makes you wonder whether it is worth it to try and convert these "old" Carl Zeiss lenses to fit the A-mount. Or am I making a mistake in my interpretation of the charts?

Cheers, Bob.
 

edwardkaraa

New member
Hi Bob,

If I understand it correctly from Zeiss' answers on this matter, Sony's MTF are measured with an 24mp A900 body while the ones from Zeiss website are measured on 400 lp/mm b&W high resolution film.
 

Eoin

Member
Having never shot with the older C/Y lenses I'm also curious as to how these newer ZA's fair up against either the C/Y or the Contax N AF lenses.

As far as I'm aware they (C/Y or N) can not be adapted to fit the alpha mount. Someone please correct me if I'm wrong.
 

fotografz

Well-known member
Having never shot with the older C/Y lenses I'm also curious as to how these newer ZA's fair up against either the C/Y or the Contax N AF lenses.

As far as I'm aware they (C/Y or N) can not be adapted to fit the alpha mount. Someone please correct me if I'm wrong.
If I recall correctly, the Contax N AF 85/1.4 was a different formula than the CY 85/1.4 ... this was apparent when I owned both lenses at the same time and shot film using an RX and N film cameras. The N 85/1.4 was the better lens.

It is difficult to tell if the N 85/1.4 is the same as the ZA 85/1.4 since I don't have comparable capture media to do a side-by-side. I guess we could look up the lens data on both and compare those. However, in practical use, the Contax N Digital with the N 85/1.4 did not exhibit the CA issue of the ZA 85/1.4 on the A900.
 

edwardkaraa

New member
The C/Y, N and ZA 85 have all different formulas. The new ZE/ZF versions have a slightly improved formula as the C/Y but basically similar. The N version is designed for portraits exclusively and shows very high center resolution that drops substantially in the corners, as you can see in Zeiss MTF. The ZA version seems the very best to date. Some associate the presence of CA to lens corner sharpness, as optical correction of CA tends to soften the performance as well. Obviously Zeiss opted to favour sharpness over other considerations for this lens.
 

fotografz

Well-known member
The C/Y, N and ZA 85 have all different formulas. The new ZE/ZF versions have a slightly improved formula as the C/Y but basically similar. The N version is designed for portraits exclusively and shows very high center resolution that drops substantially in the corners, as you can see in Zeiss MTF. The ZA version seems the very best to date. Some associate the presence of CA to lens corner sharpness, as optical correction of CA tends to soften the performance as well. Obviously Zeiss opted to favour sharpness over other considerations for this lens.
Doesn't CA affect sharpness?
 

douglasf13

New member
Eoin, there are some mount converted C/Y lenses popping up out there for Sony mount. I know that the guy I mentioned a couple of months ago, who does really nice looking Leica R to Sony conversions, is considering offering a C/Y to Sony conversion as well.
 

picman

Member
Hi Bob,

If I understand it correctly from Zeiss' answers on this matter, Sony's MTF are measured with an 24mp A900 body while the ones from Zeiss website are measured on 400 lp/mm b&W high resolution film.
Aha, yes I see, thanks for clarifying that Edward!

Cheers, Bob.
 

picman

Member
Eoin, there are some mount converted C/Y lenses popping up out there for Sony mount. I know that the guy I mentioned a couple of months ago, who does really nice looking Leica R to Sony conversions, is considering offering a C/Y to Sony conversion as well.
At first, Leitax was considering it too but my latest information is they are backing out (except for two particular lenses which for technical reasons they were able to convert quite simply).

Douglas, I contacted the person you mentioned some time ago at

[email protected]

but never got a reply. Hope I got the right address.

Cheers, Bob,
 

wayne_s

New member
The C/Y, N and ZA 85 have all different formulas. The new ZE/ZF versions have a slightly improved formula as the C/Y but basically similar. The N version is designed for portraits exclusively and shows very high center resolution that drops substantially in the corners, as you can see in Zeiss MTF. The ZA version seems the very best to date. Some associate the presence of CA to lens corner sharpness, as optical correction of CA tends to soften the performance as well. Obviously Zeiss opted to favour sharpness over other considerations for this lens.
The only other things I would add is that the N 85 is supposedly to have better smoother bokeh and sharper wide open in the center than the ZA with low CA.
But the N versions requires electronics to close the aperture down to the aperture you have selected. I just bought a N 50 1.4 to be converted for my 1ds3 by Conurus who only converts the N series for Canon. It becomes a nice AF 50 on Canon with lower CA than the Canon for less money too. The large physical mount of the N series is another problem I would think in trying to adapt it to the smaller Sony bayonet mount. Main problem is the electronic conversion needed between N and Sony.
The current Sony camera with AF Zeiss glass is the 2nd coming of the Contax N series and zoom lens designs like the N24-85 may have been dusted off and of course improved to get the current 24-70 and 16-35. Sony needs to let Zeiss take the old N 50 1.4 design and produce an excellent AF 50 1.4 lens in ZA mount. That would nicely complete the fine Sony Zeiss portrait lens trifecta of 50,85, and 135. :)
 

douglasf13

New member
I agree! Although I have the Sony 50mm, which is pretty good, a Zeiss 50mm for Sony is the lens I've been hoping for the most.
 

douglasf13

New member
I've secretly been hoping that the supposed 24mm 1.4 ZA that has been shown in prototype form is actually a 50mm 1.2 :)

 

Eoin

Member
Sorry to disappoint Douglas,

Large aperture wide angle fixed and wide angle fixed by the look of things
 

fotografz

Well-known member
Here are the data of the three types (ZA, C/Y and CZ N).

Cheers, Bob.
Hmmm, I wonder why they didn't just redo the mount the N lens for the Sony? 10 elements in 9 groups, internal focusing, sharp across the whole range, 82mm filter, no CA that I remember.
 
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