Schneider 210mm Angulon.

In article ,
John J wrote:

To me, the important point in those threads to this thread is age and
use of the lens - regardless of how good a lens might be when brand-new,
a used lens is an unknown. We cannot know how it was used, cared-for, or
stored.

Honestly, I think those factors are almost irrelevant if we're talking
about typical large-format lenses in shutters. There's almost nothing
to bend or break and problems like separation of the elements will be
pretty obvious to the naked eye. Sure, you could get a lens that someone
has omitted a spacer ring from in reassembly -- but I don't think that's
nearly enough to explain why so many old Angulons are dreadful.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper

In article ,
Peter wrote:

I agree with observation that when a Linhof tested lens acquires the
Linhof trademark it meets a high standard. I also agree that
subsequent use may invalidate any test. May I also add that Linhof
has done different tests over the years.

Clearly, when testing old lenses (say, early '50s) the performance
expected was different and so were the tests. The Linhof mark on
older lenses is still noteworthy; merely note that it may vouch for a
different level of performance.

Frankly, I think you've fallen for the hype.

There are many, many really awful Angulons out there. Some carry the
Linhof name; some don't. But when they were made, there were other
manufacturers doing far ore rigorous quality control on their large
format optics -- you will not hear tales, for example, of "really awful"
Wide Field Ektars and it's quite uncommon to run into a bad WF Dagor or
other contemporary lenses meant for applications similar to the Angulon.

It's not hard use -- other old lenses have been used hard too -- it's
that, at the time and evidently still now, people fell for some kind of
mystique of Teutonic Precision and overlooked poor quality control for
fundamentally emotional, not rational, reasons.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper

Thor Lancelot Simon wrote:
[...] it's
that, at the time and evidently still now, people fell for some kind of
mystique of Teutonic Precision and overlooked poor quality control for
fundamentally emotional, not rational, reasons.

Next thread: The Leica Glow!

Thor Lancelot Simon wrote:
In article ,
John J wrote:
To me, the important point in those threads to this thread is age and
use of the lens - regardless of how good a lens might be when brand-new,
a used lens is an unknown. We cannot know how it was used, cared-for, or
stored.

Honestly, I think those factors are almost irrelevant if we're talking
about typical large-format lenses in shutters. There's almost nothing
to bend or break and problems like separation of the elements will be
pretty obvious to the naked eye. Sure, you could get a lens that someone
has omitted a spacer ring from in reassembly -- but I don't think that's
nearly enough to explain why so many old Angulons are dreadful.

I guess one explanation could be as follows, which I observed on my Meyer
Gorlitz Aristostigmat 120 mm f/6.3. It worked fine for a year or so, then it
became quite impossible to focus. This is a 4 element 4 group lens. There
are two elements in front of the shutter, and the other two are behind.

So, since it was apart, I cleaned the elements and put it back together. Now
these elements are nearly flat, an I suppose an inadvertent person could
either put the elements in upside down, or put the front one behind the rear
one (in each pair). That would sure screw up the design and get really
dreadful optical performance.

--
.~. Jean-David Beyer Registered Linux User 85642.
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Jean-David Beyer wrote:

I guess one explanation could be as follows, which I observed on my
Meyer Gorlitz Aristostigmat 120 mm f/6.3. It worked fine for a year or
so, then it became quite impossible to focus. This is a 4 element 4
group lens. There are two elements in front of the shutter, and the
other two are behind.

So, since it was apart, I cleaned the elements and put it back together.
Now these elements are nearly flat, an I suppose an inadvertent person
could either put the elements in upside down, or put the front one
behind the rear one (in each pair). That would sure screw up the design
and get really dreadful optical performance.

Centering is what scares me with complex lenses. How can we be certain
that we replace the lenses properly? I'm just not that smart, I guess.

John J wrote:
Jean-David Beyer wrote:

I guess one explanation could be as follows, which I observed on my
Meyer Gorlitz Aristostigmat 120 mm f/6.3. It worked fine for a year or
so, then it became quite impossible to focus. This is a 4 element 4
group lens. There are two elements in front of the shutter, and the
other two are behind.

So, since it was apart, I cleaned the elements and put it back together.
Now these elements are nearly flat, an I suppose an inadvertent person
could either put the elements in upside down, or put the front one
behind the rear one (in each pair). That would sure screw up the design
and get really dreadful optical performance.

Centering is what scares me with complex lenses. How can we be certain
that we replace the lenses properly? I'm just not that smart, I guess.


I usually do not take lenses apart. In fact, the Meyer Gorlitz was the only
one where I actually separated the elements. In that lens, there was no
problem, because the design of the lens is such that you cannot help
centering it correctly (at least, the same as when it was manufactured), and
the spacing was determined by a ring between the elements.

Other lenses have shims and such to adjust the spacing.

I would expect more problems if I were to uncement the elements of a
cemented element, but even then, sometimes the lens elements are ground
after centering so it is probably sufficient to put them in a v-block before
hardening the cement (with a UV light these days, I suppose).

Richard Knoppow probably knows more about these things.

--
.~. Jean-David Beyer Registered Linux User 85642.
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In article ,
Peter wrote:

As I understood the situation we were discussing Angulons. Linhof's
tests have always been further assurance that a high standard of
quality is met for a new lens, at the time it is tested.

I just don't buy it -- I have owned a 90mm Angulon with Linhof markings
which was terrible, and seen at least one each 120mm and 210mm Linhof-
marked Angulon which were really not good. All these lenses were in
fine physical condition to any cursory examination and in one case a
non-cursory one: I had PCR check the centering of the 90mm example,
which they said was fine (though also commenting that the lens seemed
to have some serious sharpness problems at the edge of the field).

When you say "a high standard of quality", I assume you mean "a standard
of quality comparable to that maintained by other top-tier lens
manufacturers". Otherwise, how can we know what "high" is to mean? By
any objective standard I find it hard to agree that the standard of
quality Linhof applied when they were testing Angulons was "high".

I have seen descriptions of their later quality-control procedures and
agree that they sound quite rigorous. Maybe they were afraid it would
get around that they were letting awful lenses slip through and decided
to step it up. There's really no way we can know, now.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper

In article ,
John J wrote:
Jean-David Beyer wrote:

I guess one explanation could be as follows, which I observed on my
Meyer Gorlitz Aristostigmat 120 mm f/6.3. It worked fine for a year or
so, then it became quite impossible to focus. This is a 4 element 4
group lens. There are two elements in front of the shutter, and the
other two are behind.

So, since it was apart, I cleaned the elements and put it back together.
Now these elements are nearly flat, an I suppose an inadvertent person
could either put the elements in upside down, or put the front one
behind the rear one (in each pair). That would sure screw up the design
and get really dreadful optical performance.

Centering is what scares me with complex lenses. How can we be certain
that we replace the lenses properly? I'm just not that smart, I guess.

I don't often take lens cells apart. But in the cases in which I have
(generally to investigate or clean internal haze) I have never found it
possible mechanically to put them back together any way but how they came
apart -- that is, centered as the factory left them.

There may be designs where preserving centering during disassembly and
reassembly is difficult. I am aware it can be a significant problem when
repairing 35mm lenses, particularly complex zoom designs. But I don't
think it's much of an issue with typical large format optics unless you
remove not just the cell but the *cement* -- and that's just not a very
common thing to do.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper

Jean-David Beyer wrote:

I usually do not take lenses apart.

Jean-David:

I've two elements here of a Wollensak, Series IIIa, Ex WA, F/12.5 8x10.
(Reading directly around the lens.) No shutter.

Does anyone have specs for the 'tween the lens mounting? I do have
several shutters ~#3 to use. Just never felt the need to go there.

I've no idea if this is worth a thing. What ya all think? Dog? Saint?

I use a Goerz ~180mm for 8x10 when I manage to shoot 8x10) and am fairly
happy with it.

Is the Wollensak worth a darn to mount up?

jj

John J wrote:
Jean-David Beyer wrote:

I usually do not take lenses apart.

Jean-David:

I've two elements here of a Wollensak, Series IIIa, Ex WA, F/12.5 8x10.
(Reading directly around the lens.) No shutter.

Does anyone have specs for the 'tween the lens mounting? I do have
several shutters ~#3 to use. Just never felt the need to go there.

I am definitly not the person to ask this. Others on this group know way
more about these things.

I've no idea if this is worth a thing. What ya all think? Dog? Saint?

I use a Goerz ~180mm for 8x10 when I manage to shoot 8x10) and am fairly
happy with it.

Is the Wollensak worth a darn to mount up?

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 07:20:01 up 3 days, 36 min, 3 users, load average: 4.18, 4.14, 4.05