3 ZM lenses reviewed

He said the 40 nokton blew it away not the 50. On the other hand I must say im kind of disapointed by what was said abuot the 50 sonnar, I have been very interested in this lens and up till now I have not seen a decent report or group of images from this lens. I love the 50mm length and want a compact yet fast lens but kind of disapointing....
 
AusDLK said:
I find the report that the CV 50mm Nokton "blew away" the ZI Sonnar very surprising indeed.
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No, not at all when considering the context of the Sonnar's existence; which is basically a re-issue of a classic, as will be the new 21 Biogon. These two lenses are not meant as competitors to ASPH lenses. Rather, approach the Zeiss lenses in the same you would if Leica re-issued their famous 21 super angulon.

MR and Co. simply misjudged the purpose of the Sonnar, IMO.

-grant
 
I tried two of them on two different M6 bodies and finally had to give up and go to the Planar. They both front focused at wide apertures. I actually thought it was severe focus shift because they were fine when stopped down to F2.8 or smaller.

I ran about 5 test rolls through for the Sonnar and got the same results as LL...Only one of my full aperture shots was in focus...all others focused on a point ahead of the intended plane of focus.

In the end I'm glad I worked with a dealer who was outstanding in the way he handled the problem (Tony R) and love the Planar I landed on.

Best wishes
Dan
 
i own one c-sonnar, and i also had some communication with zeiss technicians about it.
they told, that it is adjusted to focus correctly at f/2.8, and because of the focus shift it will front focus at wider apertures. they will adjust it to your needs, if you want it.

beside this, with the two lenses i had in hands, i had the impression that there might be an problem with properly adjusting it. the one i keep is quite nice since it returned from zeiss germany (they adjusted it for free). both were just off - focusing did not match the rangefinder.

here i need to state an explicit "big thank you" to both zeiss and SH photo who behaved very nicely dealing with these issues.

cheers
seastian
 
sebastel said:
they told, that it is adjusted to focus correctly at f/2.8, and because of the focus shift it will front focus at wider apertures.
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I don't understand that. What focus shift are they talking about? Are they talking about the change in effective focal length that happens when focusing? From what I can see, any such focus shift should be pretty well-defined construction wise and should be easy to compensate for when designing the rangefinder helical and the focusing cam.

Philipp
 
focus shifts with different apertures.
you need to keep in mind, that rays coming in in the outer areas of the lens will show a different (shorter) focus length. as a result, the optimum focus distance shifts with the aperture. this is a result of spherical abberation.

the german technical term is "Blendendifferenz".

pls also see wikipedia:
http://upload.wikimedia.org/wikipedia/de/thumb/0/02/Sphaerische_Aberration.png/300px-Sphaerische_Aberration.png

you can only compensate if you make the aperture selector have an influence on the focusing cam - looking at the amount of the necessary correction, this will be too expensive.

cheers
sebastian
 
Why don't the Noctilux or Summilux have the same problem? Do those lenses have a progressive cam dependent on aperture? What's the point of having 1.5 if you can't use it or if you want it in focus at 1.5 you need to accept fuzzy results at smaller apertures.

I was thinking of a ZM 21 and the 1.5 for my future M8 but it sounds like the 1.5 lens is unusable.
 
HAnkg said:
Why don't the Noctilux or Summilux have the same problem?
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well, they have.
but, both lenses are a different construction. the noctilux is more of the planar type where the effect shows up less intense, and the summilux is an aspherical construction, where especially SPERICAL abberation should be corrected to a much higher degree.

HAnkg said:
What's the point of having 1.5 if you can't use it or if you want it in focus at 1.5 you need to accept fuzzy results at smaller apertures.

I was thinking of a ZM 21 and the 1.5 for my future M8 but it sounds like the 1.5 lens is unusable.
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that's up to you.
if you want a sonnar, you'll get one, with all properties of this design.
if you cannot live with these properties, you better get something different.

by the way, there are NO fuzzy results with smaller apertures.

looks like i opened pandora's box.
now i wish i had not mentioned this at all.

just one more word: my sonnar delivers fine results, and i am very happy with it.
but, i won't give away my summicron (it just happens to be a summicron, could be a planar as well) - they are just different lenses.
 
sebastel said:
if you want a sonnar, you'll get one, with all properties of this design.

by the way, there are NO fuzzy results with smaller apertures.
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I'd like to get a better understanding of what the 50 sonnars limitations are because I certainly like the imaging signature (when the subject is in focus).

Does the Sonnar have a narrower DOF?
Is it a problem in the near range, do you need to avoid subjects closer then say 3 meters?

If you have the lens optimized for focus at 1.5 will it back focus at 2.8?

When would you use the Sonnar and when would you reach for the Planar or Summilux? Zeiss must have had some particular application in mind when they produced the lens knowing the designs percularities. Thanks in advance for any illumination on the subject as I have not seen much on this lens that gives a real sense of its capabilities or limitations.
 
HAnkg said:
Does the Sonnar have a narrower DOF?
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no.

HAnkg said:
Is it a problem in the near range, do you need to avoid subjects closer then say 3 meters?
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no.
the focus shift is ONLY related to the aperture. measuring as percentage, the effect should be independent from focus distance. measuring in absolute focus difference, the effect is larger at large distance, smaller at close up.

HAnkg said:
If you have the lens optimized for focus at 1.5 will it back focus at 2.8?
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yes.
the problem here is, that the design will always be a compromise.

usually, the effect is small enough to "drown" in depth of field for smaller aperture, so you can safely optimize for full open.

as soon as the effect gets stronger, you need to decide where you can accept a deviation from the expected technical behaviour.

for a correctly adjusted lens, the effect should be quite small - just noticeable.

please note, that i can tell only from observing it on one lens, and without knowing the exact specification for lens adjustments given by zeiss.

HAnkg said:
When would you use the Sonnar and when would you reach for the Planar or Summilux?
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summicron.
i own the summicron, not the summilux.

to put it compact:
i'll use the sonnar, when i want the sonnar's imaging properties, and the summicron, as soon as i want the summicron's.

as you already said: the sonnar has its special signature.
i regard the summicron as something like a "reference lens".

let's say, for example portrait:
summicron --> neutral or analytic (i don't like the term "clinical" ...)
sonnar --> expressive, "dreamy"

don't nail me on this comparison - the differences are subtle, highly subjective and lie in the eye of the beholder.

asking, which 50mm would i take on the far away island?
answer:
the sonnar.

HAnkg said:
Zeiss must have had some particular application in mind when they produced the lens knowing the designs percularities. (sic)
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sure.
it is a classical lens, reborn.
 
sebastel said:
...

you can only compensate if you make the aperture selector have an influence on the focusing cam - looking at the amount of the necessary correction, this will be too expensive.
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When Zeiss started the ZM range, they stressed that these lenses were extremely well corrected with respect to aperture related shifts of the focal length (spherical aberation). I guess the Sonnar C is not one of them. Actually people often prefer lenses with significant spherical aberations when it comes to discussing the out-of-focus image (Bokeh). Seems a case of you can't have it all ...

If one actually reads the Zeiss publications incl. the MTF, distortion and vignetting data (http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CSonnar_1.5_50_ZM.EN/$File/CSonnar_1.5_50_ZM.EN.pdf) it is clear that this is not supposed to be "the sharpest" 50 there has been. When it comes to MTF, the Plannar 50/2 is just better (http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/Planar2.0_50mm_ZM_e/$File/Planar2.0_50mm_ZM_e.pdf). Emphais in the C-Sonnar marketing is given to compact size, flare and distortion control. There is a reason why "all" manufacterers went for modified double Gaussian designs (Planar in Zeiss speak) in the second half of the 20th century when ultimate sharpness was the key aim.

Please get my right, I am not saying the C-Sonnar sucks. Just ultimate sharpness was not one of it's design goals.

So the review at luminous landscape did only discover what Zeiss marketing tells you anyway. Where is the beef?

With respect to the Nokton 40/1.4 there seems to be a bit of scatter. The guys at LL seemed to have gotten a very good sample. The British mag "AP" was more luke warm when they reviewed it: about what you expect for the price and spec, but nothing outstanding.
 
i just doublechecked to evaluate the actual amount of focus difference.

at f/1.5 at 0.95 m distance, the focus difference is about 9-10 mm - that is a bit less than the DOF at this aperture.

please note, that DOF seems to be more shallow on digital sensors.

the noctilux for example also shows focus difference. at f/1.4 it is smaller compared to the sonnar, but at f/1 it looks to me to be about the same amount (if not more) like the sonnar at f/1.5.

after all, it is exactly the abberations that make the sonnar so special. assuming you have a correctly adjusted one, the abberations are not neglectible, but can be conquered. whether this (from my point of view small) effort is worth while everyone needs to decide for her/himself.
 
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