Unlike other Zeiss lenses I have, this ZA 24mm Sonnar does not come with usual Zeiss MTF chart and optical structure diagram. It has not been listed on official Zeiss website. From a Chinese website, I finally got the information I have looking for. Hope they will help dicussion about this interesting lens. Sonnar or not, you be the judge.
Unfortunately, unlike non za Zeiss lenses, the mtf is only theoretically computed and not measured from a real lens. Thus, actual performance will be lower.
Tariq Gibran wrote:
Unfortunately, unlike non za Zeiss lenses, the mtf is only theoretically computed and not measured from a real lens. Thus, actual performance will be lower.
How do you know it isn't measured? Because of Sony or because of it is APS-C? Thx
iskraII wrote:
How do you know it isn't measured? Because of Sony or because of it is APS-C? Thx
All you have to do is look at the F8 MTF chart and note the red line for 10 cycles which is right at 100 on the vertical axis in the center of the lens (0 on the horizontal axis). This is an impossible measurement for a real lens. Look at the best Zeiss and Leica measured MTF's and you will not find one which is this high. That's pretty much a dead giveaway this MTF is not real world measured.
The problem is that the nomenclature is not consistant with other Zeiss Z named lenses which are named for the mount they fit onto. We have the ZF for F mount, ZK for K mount and the ZE for the EF mount. Since the Minolta/ Sony SLR AF mount is universally known as the A mount, logic would dictate only those lenses intended for the A mount would be called ZA. This would follow the previous naming scheme above. Saying that ZA stands for Zeiss autofocus would suggest that any Zeiss autofocus lenses designed for Canon or Nikon would be called ZA, and that will never happen. ZA is specific to Sony. Sony created confusion by naming E-mount Zeiss lenses ZA, the same nomenclature used for the A mount...and you can bet this was a Sony choice.
Anything reporting a number higher than this (it is of course possible, but you have to resort to solutions like wavefront-controlled light collimation, not very probable in a photographic lens case...) is either calculated, or they've cheated really bad.
The MTF charts here should be compared to MTF charts from other Sony lenses, If you know a "good sample" from a similar Sony lens/report system then you can take an educated guess at what the lens will be like - in relation to the "other lens".
Tariq Gibran wrote:
The problem is that the nomenclature is not consistant with other Zeiss Z named lenses which are named for the mount they fit onto. We have the ZF for F mount, ZK for K mount and the ZE for the EF mount. Since the Minolta/ Sony SLR AF mount is universally known as the A mount, logic would dictate only those lenses intended for the A mount would be called ZA. This would follow the previous naming scheme above. Saying that ZA stands for Zeiss autofocus would suggest that any Zeiss autofocus lenses designed for Canon or Nikon would be called ZA, and that will never happen. ZA is specific to Sony. Sony created confusion by naming E-mount Zeiss lenses ZA, the same nomenclature used for the A mount...and you can bet this was a Sony choice....Show more →
Well, ZE was taken, and I guess Sony wanted to keep some brand recognition too. What else could they have called it, ZN (N for NEX)? Sony shouldn't have called it E-mount, if they had been looking ahead a bit.
Tariq Gibran wrote:
The problem is that the nomenclature is not consistant with other Zeiss Z named lenses which are named for the mount they fit onto. We have the ZF for F mount, ZK for K mount and the ZE for the EF mount. Since the Minolta/ Sony SLR AF mount is universally known as the A mount, logic would dictate only those lenses intended for the A mount would be called ZA. This would follow the previous naming scheme above. Saying that ZA stands for Zeiss autofocus would suggest that any Zeiss autofocus lenses designed for Canon or Nikon would be called ZA, and that will never happen. ZA is specific to Sony. Sony created confusion by naming E-mount Zeiss lenses ZA, the same nomenclature used for the A mount...and you can bet this was a Sony choice....Show more →
what about the m42 zeisses? they aren't called ZM because its already taken. they're called ZS for screwmount.
sebboh wrote:
what about the m42 zeisses? they aren't called ZM because its already taken. they're called ZS for screwmount.
Still refers to the mount.
Well, more Alpha Zeiss than Zeiss Alpha.
AZ has a better sense of direction to it, like alpha-omega.
Back to the fictional world of computed MTF reality, once you allow a fudge factor in the charts at the top of this thread, the lens seems pretty poorly behaved at f8, for users after decent cross frame, fine detail performance. Each line has seemingly developed a mind of its own. Pretty tidy at wide open aperture however, even at 15% off.
This is one good example why I wish CZ would publish the ZA lens data on their own website along with their other designs, past and present. Measured on an optical bench along with the others, thank you.
On all accounts I've read (Digllyod, Steve Huff to name 2) and shots I've seen, it seems like it will be a winner. Maybe not razor sharp at 1.8, but lots of character, good color and Zeiss contrast. It is certainly bigger than the m4/3 options, but from the spec, it's quite light. I'm definitely going to try it out with my Nex 7, assuming that ever arrives.
Yeah, I have the Contax G 45mm F2 and it's a phenom lens when I can nail the focus but I've found I've missed focus on about 50% of shots if I'm trying to do a quick or candid portrait of my friends or life.
It's just frustrating so I think this lens might do the trick and I'll be able to use ambient light. Every review says that the AF is spectacularly fast and with Contrast detect, should be 100% accurate.
If I need to do landscapes, I'll break out the Contax G 45mm.
It does seem to have an unusually large amount of CA for a F1.8 APS-C lens without OSS at $1000 but choices are pretty limited.
It's a lens with some definite character. Expect it to be very good close in and in the centre, it gets weaker at the edges and at infinity, but remains quite acceptable in performance, especially stopped down. The corners do get a lot better when stopped down.
My experience is it's great at wide apertures and short/mid focal distances and quite good at infinity when stopped down to f5.6-8. Rendering is very much a Sonnar look, so somewhat smoother than your typical Zeiss Planar or Distagon.
