[Leica] Zeiss Ikon Focus Shift

[henningw at archiphoto.com (Henning Wulff)]

At 8:32 PM -0500 1/11/05, Bill Marshall wrote:
>On Monday, Richard wrote:
>>"Well, since I am one of the people that calls it "smelling of 
>>marketing hype," let me reiterate why I thought so:
>- stress on high resolution when most experts say what are they smoking?"
>
>Richard, I assume that you are referring to the 400 lp/mm claim. I 
>don't know who the so-called "experts" are. The only one I read who 
>wrote about it at any length was Erwin Puts & he did so in rather 
>scathing terms. It's interesting that Kornelius Fleischer, who did 
>the testing for Zeiss that resulted in the high resolution claim, 
>responded to Erwin on a public forum (photo.net). If you didn't see 
>it, you can find it under the topic "Can ZM lens really resolve 
>400lpm???", posted by Arthur Yeo on October 24. Fleischer's post is 
>fairly lengthy & was posted on October 29; if you scroll down, you 
>will find it. Read it & see what you think about who is smoking 
>what. The url is: 
>www.photo.net/bboard/q-and-a-fetch-msg?msg_id=009t9L
>
>>"- stress on high RF baselength when only one lens (85/2) would benefit."
>
>Richard, I dispute the claim that only one lens will benefit. Is 
>this criticism saying that it's not a good thing to have a more 
>precise rangefinder & that all lenses won't benefit from focusing 
>with it? First, a longer bae line will minimize the effect of the 
>range of tolerances - whatever that range is. Second, a longer base 
>line will also focus more effectively with all lenses when they are 
>shooting close up - & especially close up & wide open. Have you 
>noticed that the CV Bessa R2, for example, is rangeinder coupled 
>only to 0.9 meter (35")? The ZI is rangefinder coupled to 0.3 meters 
>(12"). Huge benefit for all the ZI lenses! Finally, the ZI isn't 
>restricted to its own lenses. It's an M-mount camera that can use 
>any M-mount lens; it will handle all of those super fast Leica & CV 
>lenses & will focus them beautifully.
>
>>" Also again, doesn't the RF mechanism need to be of higher quality 
>>for the focusing accuracy to show there?"
>
>Since none of us have any idea what the quality is, we have no idea 
>whether it needs to be of "higher quality." Some of us have 
>impressions from photo shows, but none of us have inspected the RF 
>mechanism to see how well built it is. Hopefully it is of high 
>quality & hopefully Zeiss has spec'd it for tight tolerances. But 
>even it it of exactly the same quality as other Cosina-built RF 
>mechanisms, its length alone will make it a more effective 
>instrument. For example, if Cosina builds in a tolerance of +/- 1 
>mm, this will represent a potential error of +/- 1.3% or a total 
>error range of 2.7% on the ZI. On the Bessa cameras, the same 1 mm 
>tolerance = +/- 2.7%, or an error range of 5.3%. In other words, the 
>same tolerance will have double the effect on the shorter base line 
>because it is half as long.
>
>>"- stress on focus shift without showing its benefits"
>
>Simply put, I think that this whole focus shift issue was just 
>techno-speak for saying "We made these lenses as sharp as modern 
>lenses can possibly be made." Poor choice of marketing strategy to 
>get overly technical, perhaps, but not really a knock on the product 
>nor should it diminish expectations to the point where we say "It's 
>all just hype & nothing more." Yes, there's been hype, but I think 
>that there is substance behind it. The Zeiss reputation alone should 
>suggest that.

And that is all we have to go on. That, and the quality that we have 
seen from Cosina to date, as they will be producing not only the 
majority of the lenses but also most, if not all of the body. The 
quality on evidence at Photokina was not convincing as a realistic 
alternative to Leica products. The lenses were of a standard 
comparable to the better Cosina products, which is very good but not 
the same as Leica's. None of the bodies I handled were fully 
operational, but that was because something had failed on all of them 
during Photokina before I got to them. I don't believe that it would 
be at all fair to assume that the failures of the bodies will carry 
over into production, nor that the lousy finishes will, either on the 
lenses nor on the bodies.

As far a the lenses are concerned, Dr. Hubert Nasse of Zeiss, with 
whom I spoke at some length at Photokina, indicated that the lenses 
were the design of Zeiss, with production design, ie, glass types 
tuning and manufacturing details determined by Cosina. Mr. Kobayashi 
indicated that Cosina did most, if not all of the design. The 85 and 
15 are purely Zeiss products, and don't even look like they are part 
of the same family. Unfortunately, the family branch that the Zeiss 
lenses are part of is the severely obese side of the family. I'm not 
really interested in a 15/2.8 that is closer in size to an SLR 14 or 
15/2.8 than a usual M mount lens, and the 85 is also rather plus 
sized.

So I hope that the Zeiss/Cosina/Voiglander/Hasselblad lenses from 21 
to 50 are built to a higher standard than we've seen heretofore from 
Cosina, the 15 and 85 are worth their high price and large weight and 
size, and the bodies are significantly better built than the 
Photokina examples. I hope, and won't know until they come out.

The 85 I don't care about, as the 90AA sets a standard that will be 
hard to reach, let alone surpass and is smaller than the 85. The 15 
will need to be truly exceptional to convince me, and some of the 
other lenses are interesting, but I can get used Leica lenses of 
proven and outstanding quality for the same price. That leaves the 
body. I'll wait and see, but I'll continue using my Konica RF bodies 
quite happily for the shorter lenses, which its viewfinder is 
eminently suited for. The Konica's quality is certainly higher than 
that of the bodies Zeiss/Hasselblad showed.

The Zeiss body might be just the thing for the longer lenses, but 
again, a used Leica M7 body can be had for the same price.

For film, all the Zeiss offerings don't make a lot of sense to me. 
When (or if) Zeiss make a digital body, and show that their lenses 
work a lot better with it than the other lenses out there, this could 
all change. Until then, we have only Zeiss' word for the benefit of 
any of these products.

-- 
    *            Henning J. Wulff
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