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Nikon Nikkor 105mm F2.5 AI
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PostPosted: Fri Nov 27, 2009 1:45 am    Post subject: Reply with quote

larsr wrote:
Sorry to repeat, but could someone just please clarify, which version of the 105/2.5 is Gauss, and which Sonnar?

This thread made me seasick Very Happy


The earlier version is the Sonnar. The AI and AIS is Gauss. I do not know the exact cut off point date wise however (ie was the transition made at the same time as the AI mount - I am not sure) but if you check out the site below you may find exactly where the transition occurred. The reason for my uncertainty is that there were several sub variants with the early versions of the lens.

http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/preAI70/105mm.htm

On a quick read the site says "The most important change of this lens may be occurred between 1971- 1973 (500001). The lens has a modified optical design where its old optical formula of 5 elements in 3 groups being reverted to an existing 5 elements in 4 groups construction. " This suggests that the change was made before the move to AI but I have not researched this properly.

Although the gauss design is regarded as technically better I prefer the Sonnar signature. It is kinda unique especially for portraits.


PostPosted: Fri Nov 27, 2009 1:55 am    Post subject: Nikkor P 105 2.5 Reply with quote

The first and second version (P) is a sonnar, then change the optical formula and is a double gauss, more focus but worse bokeh.
Upload photos soon made with a 105 P, the second version.


PostPosted: Fri Nov 27, 2009 6:30 am    Post subject: Reply with quote

I prefer the first version, the colour tone is much warmmer and nicer, although the later model sounds interesting.
How much does it worth? Humm... it depends on how much you want to get from this lens Laughing


PostPosted: Fri Nov 27, 2009 9:02 am    Post subject: Reply with quote

peterm1 wrote:
larsr wrote:
Sorry to repeat, but could someone just please clarify, which version of the 105/2.5 is Gauss, and which Sonnar?

This thread made me seasick Very Happy


The earlier version is the Sonnar.


Yes.

peterm1 wrote:
The AI and AIS is Gauss.


No. Its Xenotar.

peterm1 wrote:
I do not know the exact cut off point date wise however (ie was the transition made at the same time as the AI mount - I am not sure)


No, it wasn't the same time as the switch to AI mount.

(guesswork deleted).


PostPosted: Fri Nov 27, 2009 9:09 am    Post subject: Reply with quote

Sven wrote:
ChrisLilley wrote:

Here we go again. No, the P.C is the newer version; and its a Xenotar design, not a Gauss design.

Is today "post inaccurate Nikon-related info day" or something? Or does the search not work?


Well, sorry for quoting an inaccurate source.


The source is accurate. You quoted it inaccurately, or didn't read it closely enough.

Sven wrote:
According the the above Nikon link the Xenotar is a modified Gauss design so I can see how the mistake has been made.


Yes, lots of lens designs are derived from other designs. And according to the link you quoted, the design change happened when the lenses were still being listed as "auto" (auto-aperture, ie not stop down), which corresponds to the first Nikkor-P designation.

Yes, despite that link to Nikon desgn description, and despite earlier posting s that identified exactly when the change happen, we still have later postings muddying the waters with faulty remembering or guesswork, apparently its too hard to follow and read links or to actually read other postings in the thread? Rolling Eyes

Sven wrote:
I belive the question was more aimed at finding out if it's a good lens and what it usuallay sells for and in that sense most information here is still valid.


Around 50% of the responses confidently assigned it to the wrong optical design.

Look, people hit these threads through Google. The newer threads tend to come up higher. Some questions (like this one) come up repeatedly, people put in effort to get the accurate information, then it starts again in a new thread with people posting wild guesswork, hearsay, or faulty summarizing and off we go again.

Sven wrote:
In my view it's a very good lens for general use if one likes short telephoto lenses.


Of course it is. Its a pretty famous lens, well regarded.

The value to a photographer is much higher than its financial value, which is currently modest.


PostPosted: Fri Nov 27, 2009 12:37 pm    Post subject: Reply with quote

ChrisLilley wrote:
Sven wrote:
ChrisLilley wrote:

Here we go again. No, the P.C is the newer version; and its a Xenotar design, not a Gauss design.

Is today "post inaccurate Nikon-related info day" or something? Or does the search not work?


Well, sorry for quoting an inaccurate source.


The source is accurate. You quoted it inaccurately, or didn't read it closely enough.



This is my original statement: "Acc. to Björn Rörslätt the older one is a Sonnar design while the newer PC is a Gauss design."
Plese check this link and see if he anywhere mentions "Xenotar" in connection with the 2.5/105. I might be wrong but I can't see it.
http://www.naturfotograf.com/lens_short.html
I can see that the designation PC not nessecarily signifies the new design so that could perhaps have been a bit misleading in my statement, but not entirely incorrect since the C (multi-coating) was not present on the old design.




ChrisLilley wrote:
Sven wrote:
I belive the question was more aimed at finding out if it's a good lens and what it usuallay sells for and in that sense most information here is still valid.


Around 50% of the responses confidently assigned it to the wrong optical design.

Look, people hit these threads through Google. The newer threads tend to come up higher. Some questions (like this one) come up repeatedly, people put in effort to get the accurate information, then it starts again in a new thread with people posting wild guesswork, hearsay, or faulty summarizing and off we go again.


I can understand your frustration. The truth has been written once, and then new postings tend to distort it.
I can't see how this could be entierly avoided though.
A forum like this will inevitably be populated by people with different areas of skills and knowledge levels. Personally I think that's what makes it interesting.
I realise that it might be annoying for the experts in the forum to continously have to correct the less enlightened ones, but isn't that the whole point, that we learn from each other.
It's a balance really. Tell peolple to avoid posting unless they are 100% certain of all facts and get correct but probably not so many threads. Or, leave it as it is and get many, but sometimes incorrect postings.
I agree that this thread got unusually messy regarding the optical design, bit maybe that's the price to pay for having an open and lively forum.


Last edited by Sven on Fri Nov 27, 2009 5:06 pm; edited 2 times in total


PostPosted: Fri Nov 27, 2009 3:18 pm    Post subject: Reply with quote

Yes, I'm wrong. The optical formula becomes Xenotar (Gauss type?) Models, PC, AI, AIS. etc.
There are six or more models, one of the last with 5 blades diaphragm.
I enclose two pages where more information see.
http://www.naturfotograf.com/lens_short.html
http://imaging.nikon.com/products/imaging/technology/nikkor/n05_e.htm

Greetins, sniper.


PostPosted: Fri Nov 27, 2009 3:45 pm    Post subject: Reply with quote

I did some research and cross-referencing on the net and this data on the 105/2.5 is based on my sourced findings.

There would seem to be five(5) distinct types of 105/2.5 lenses, and two(2) optical construction derivatives within those five types. Each type has at least one slightly varied subversion to confuse things.
The main types are the following:

1. 105/2.5 P-version (Optical design 5/3)
2. 105/2.5 multicoated P -version (Optical design 5/4)
3. 105/2.5 K-version (Optical design 5/4)
4. 105/2.5 AI version (Optical design 5/4)
and
5. 105/2.5 AIS version (Optical design 5/4)
Source: Roland Vink/Photosynthesis, see column "optic".

The Schneider Xenotar, Gauss and Sonnar-type designs are all individually different designs as follows:

* Schneider Xenotar is a 5/4 design, based on the Gaussian design
Source: Nikon, see "1. Lens structure and features"
Source: Wikipedia


* Gauss (or Gaussian, or Double Gauss as it is synonymously known) is a 6/4 design
Source: Nikon, see "G. Gaussian (Gauss-type) lens"

* Sonnar (combination of the Ernostar and Tessar) has two derivatives, both post-war, 7/3 and 6/4
Source: Nikon, see "1. The Sonnar-type lens and the Gauss-type lens"
Source: Wikipedia


However, based on this alone, one would come to the conclusion that only the versions after the first P-version would be Xenotar, and they would all be Xenotar-type.
Yet Nikon say that the 10.5cm/2.5 P was a 5/3 Sonnar design, even though they on the Sonnar-type page say that the Sonnar only had two variations, namely the 7/3 and 6/4. The 105/2.5 page also does not talk about Gauss designs at all.

I am very puzzled here, as I was under the impression that there would only have been two variations of the Sonnar.

So it would seem that actually none of these are the real Gaussian designs, only modified versions of the Gauss design.

I'm looking for further black-on-white, sourced proof to work this out further.
I am pretty sure I'm also missing something.


PostPosted: Fri Nov 27, 2009 4:38 pm    Post subject: Reply with quote

larsr wrote:
I did some research and cross-referencing on the net and this data on the 105/2.5 is based on my sourced findings.


Excellent. I very much appreciate the depth of research and also the citation of sources.

larsr wrote:
There would seem to be five(5) distinct types of 105/2.5 lenses, and two(2) optical construction derivatives within those five types.


Since the earliest Nikkor-P 105/2.5 came in both optical constructions, it should count as two types and thus, the total number of types is six.
Source: Bjørn who says
Quote:
The first batch evidently were released without multi-coating and carried the 'P' designation (I own one of them), but these were quickly replaced by multicoated 'P·C'-labelled lenses.

Source: me (I also own a Nikkor-P which is of the second, Xenotar type).
Serial: 427030 Marking: Lens Made In Japan


Its possible to tell the two different Nikkor-P apart, because the older optical design has a silver-colored "nose" (the part of the barell closest to the front element) like this



while the later, Xenotar type has a black nose

Notice that this one says Nikkor-P not Nikkor-P.c and also that it says "auto".

Source: Roland Vink, specs
The thick blue line between the two Nikkor-P indicates a design change, in Roland's layout.

Another way to tell is by serial number, the last batch of old-design 105/2.5 have the serial numbers starting 234011 and covering at least the range 234380 - 286276
Source: Roland Vink, serials

while the remainder of the Nikkor-P, with the new design, have two sets of serials

a) starting 407301 and covering at least 407493 - 408125
b) starting 409001 and covering at least 409383 - 471485
type a)is labelled Nippon Kogaku Japan while type b) is labelled Nikon.
Source: Roland Vink, serials

To correct your original table, then, we have six types

1. 105/2.5 P-version, silvernose (Optical design 5/3)
2. 105/2.5 P-version, blacknose (Optical design 5/4)
3. 105/2.5 multicoated P.C -version (Optical design 5/4)
4. 105/2.5 K-version (Optical design 5/4)
5. 105/2.5 AI version (Optical design 5/4)
and
6. 105/2.5 AIS version (Optical design 5/4)
Source: Roland Vink/Photosynthesis, see column "optic".

larsr wrote:
The Schneider Xenotar, Gauss and Sonnar-type designs are all individually different designs as follows:

* Schneider Xenotar is a 5/4 design, based on the Gaussian design
Source: Nikon, see "1. Lens structure and features"
Source: Wikipedia


Yes. Nikon refer to it as a Xenotar-type design, and this seems to be correct. Bjørn refers to it as a Gauss design, which is incorrect, but as its a derivation of a double Gauss perhaps that is where he was misled.
I will contact Bjørn and ask if he could make a correction.

larsr wrote:
* Sonnar (combination of the Ernostar and Tessar) has two derivatives, both post-war, 7/3 and 6/4
Source: Nikon, see "1. The Sonnar-type lens and the Gauss-type lens"
Source: Wikipedia


However, based on this alone, one would come to the conclusion that only the versions after the first P-version would be Xenotar, and they would all be Xenotar-type.


Agreed.


larsr wrote:
Yet Nikon say that the 10.5cm/2.5 P was a 5/3 Sonnar design, even though they on the Sonnar-type page say that the Sonnar only had two variations, namely the 7/3 and 6/4. The 105/2.5 page also does not talk about Gauss designs at all.

I am very puzzled here, as I was under the impression that there would only have been two variations of the Sonnar.

So it would seem that actually none of these are the real Gaussian designs, only modified versions of the Gauss design.


Yes. There is no Gauss-design 105/2.5 from Nikon.

And as you point out, it seems that it may be incorrect to call the first type Sonnar. I am not sure about this, however. Pending confirmation I have just referred to it as the "earlier design".


PostPosted: Sat Nov 28, 2009 3:25 pm    Post subject: Reply with quote

Thank you Chris!

This is excellent, proofed information which should rectify all misconceptions people have about this lens.

I started investigating myself because it really bugs me when people talk about things as if they were facts, without any kind of proofing.


PostPosted: Sat Nov 28, 2009 10:18 pm    Post subject: Reply with quote

ChrisLilley wrote:
And as you point out, it seems that it may be incorrect to call the first type Sonnar. I am not sure about this, however. Pending confirmation I have just referred to it as the "earlier design".


It is a clone of the original Carl Zeiss Sonnar, so its design is, naturally, a Sonnar design. Note that the early 105/2.5 is a derivative of Nikon's rangefinder series 85/2, which, in its turn, is a direct copy of pre-war Zeiss Sonnar 85/2.

These are Carl Zeiss Sonnar 135/4, Sonnar 135/3.5, and Sonnar 180/2.8:



Nikon 135/2.5 (early):


Sonnar 85/2 and Jupiter-9:



EDIT: one more diagram of pre-war Sonnar 85/2:



Nikon's 85/2 and Nikon's 105/2.5 'Sonnar' design. There's almost no difference in optical layout of the 85 and 105mm lenses:


Finally, Nikon's 105/2.5 'Xenotar' design:
[/img]


Last edited by aoleg on Sun Nov 29, 2009 12:45 am; edited 2 times in total


PostPosted: Sat Nov 28, 2009 10:44 pm    Post subject: Reply with quote

aoleg wrote:
It is a clone of the original Carl Zeiss Sonnar, so its design is, naturally, a Sonnar design. Note that the early 105/2.5 is a derivative of Nikon's rangefinder series 85/2, which, in its turn, is a direct copy of pre-war Zeiss Sonnar 85/2.


I am puzzled by this statement. I'm no expert on optics, but to me, "clone" means 'identical.' Is the Sonnar 85/2 (in blue) the pre-war Sonnar 85/2? If so, then there is substantial difference between this design, both in number of elements and shape, than the Nikkor 85/105. In fact, the Nikkor design is noticeably different from all the Sonnar designs you show, whether in number of elements, or element shapes.

I can see why Nikon referred to their 105/2.5 as a Sonnar type, since there is some general resemblance to the above formulas. But not specific resemblance, which I guess makes it their own flavor of a Sonnar design.


PostPosted: Sat Nov 28, 2009 10:57 pm    Post subject: Reply with quote

I agree about the wording.
"Clone" should be used only when the lens is identical and made as a perfect copy on purpose.
For instance, the Jupiter-9 is a clone of the Contax Sonnar 2/85
And the Industar 3.5/50 is a clone of the Tessar 3.5/50, and the Helios-44 is a clone of the Biotar 2/58.

When the copy is not a "perfect copy", I think we should use the simple word "copy", or "derivative".


PostPosted: Sat Nov 28, 2009 11:32 pm    Post subject: Reply with quote

larsr wrote:
I started investigating myself because it really bugs me when people talk about things as if they were facts, without any kind of proofing.


It's all very well complaining about people who make mistakes with proofing. It's sometimes difficult to make the connection between referenced statements and the references themselves. For example...

larsr wrote:

* Sonnar (combination of the Ernostar and Tessar) has two derivatives, both post-war, 7/3 and 6/4
Source: Nikon, see "1. The Sonnar-type lens and the Gauss-type lens"
Source: Wikipedia


The Nikon source takes us here....

http://imaging.nikon.com/products/imaging/technology/nikkor/n40_e.htm

I've looked very hard but I can't find the reference to a 6/4 Sonnar although there is reference to 6/3 and 7/3 Sonnars and a 6/4 Gauss. The Wiki source refers to a 6/3 Sonnar. Am I missing something ? Given my previous record I might be - but I can't see the 6/4 Sonnar. The
Ernostar-Tessar reference is given here...

http://imaging.nikon.com/products/imaging/technology/nikkor/nwords-e.htm#sonnarty

but I can't find it your source.

larsr wrote:
Nikon say that the 10.5cm/2.5 P was a 5/3 Sonnar design, even though they on the Sonnar-type page say that the Sonnar only had two variations, namely the 7/3 and 6/4.


I'm not sure that they say that there were only two types. Here's the quote..

The Sonnar-type lens, which was discussed in Tale 34, can be configured as a three-group, six-element lens, as shown in Figure 1, or as a three-group, seven-element lens, with the rear group comprised of three elements.

Nikon appear to be referring to the Sonnar type lens which was discussed in Tale 34 which is is 6/3 Sonnar discussed here ...

http://imaging.nikon.com/products/imaging/technology/nikkor/n34_e.htm

This source provides a further reference....

http://imaging.nikon.com/products/imaging/technology/nikkor/n33_e.htm

This is a 5 element Sonnar. Quote...

This lens was designed with a Sonnar-Type lens configuration that Nippon Kogaku K.K. used for a long time.

I'm not always sure how to count the elements so I'm not sure whether or not it's 5/4 or 5/3. Anyway, if you replace the air gap between the 2nd and 3rd elements with an extra element and cement the three together you get the 6/3 referred to earlier.

Replacement of the rear elements (a cemented doublet - I'm not sure that this is technically correct but there are two of them - glued together) in the 6/3 Sonnar with a single elemnet would give a 5/3 with a configuration matching that of the 2.5/105 Sonnar P

http://imaging.nikon.com/products/imaging/technology/nikkor/n05_e.htm

Maybe, and this is only a guess, this is why Nikon refer to the early 2.5/105 as a Sonnar.

larsr wrote:
I am very puzzled here, as I was under the impression that there would only have been two variations of the Sonnar.


Are you refering to Nikon lenses only ? If not there are lots of variations...

CZJ 3.5/135 and 4/135 both 4/3
CZJ 2.8/200 and 4/300 both 6/4

http://www.praktica-users.com/lens/mlenses.html

Ziess ZA Sonnar T* 135mm f/1.8 11/9

http://www.photozone.de/sony-alpha-aps-c-lens-tests/381-zeiss_za_135_18

Sonnar is a Registered trademark of Zeiss and they can use it how they like.

Of course I've no idea if any of this is true but the references might be useful.


PostPosted: Sun Nov 29, 2009 12:37 am    Post subject: Reply with quote

John,

my purpose was not to attack you or anyone else participating in this thread - what I said was not meant to be directed at discussion in this thread, rather, at any and all people I've conversed with who stood up to their words with no proof whatsoever, only to be later stood, well, corrected. I am sure you know the type.
My motive is to spark discussion and investigation, not war and flaming - and I do apologize if this was the way you or anyone else might have understood it.

I also originally wrote:
larsr wrote:
I am pretty sure I'm also missing something.


All that said, I'm also very thankful for the work (and the depth of it) you brought in. I'll try and see if I could pull together a referral of some sort (if Chris doesn't manage first :)


PostPosted: Sun Nov 29, 2009 12:43 am    Post subject: Reply with quote

cooltouch wrote:
aoleg wrote:
It is a clone of the original Carl Zeiss Sonnar, so its design is, naturally, a Sonnar design. Note that the early 105/2.5 is a derivative of Nikon's rangefinder series 85/2, which, in its turn, is a direct copy of pre-war Zeiss Sonnar 85/2.


I am puzzled by this statement. I'm no expert on optics, but to me, "clone" means 'identical.' Is the Sonnar 85/2 (in blue) the pre-war Sonnar 85/2? If so, then there is substantial difference between this design, both in number of elements and shape, than the Nikkor 85/105. In fact, the Nikkor design is noticeably different from all the Sonnar designs you show, whether in number of elements, or element shapes.


While I agree on the wording ('clone' is probably a strong statement for comparing the two 85/2 lenses), I clearly see the resemblance between these optical formulas. If anything, Nikkor 85/2 and early 105/2.5 have the optical scheme derived from Sonnar 180/2.8, probably the very first Sonnar ever built en masse. Therefore I have no problem classifying Nikon's 85/2 and early 105/2.5 as Sonnars.

BTW, here's another Sonnar from Nikon, this time 135/3.5. Try finding the difference between this and Jena:



PostPosted: Sun Nov 29, 2009 2:35 am    Post subject: Reply with quote

larsr wrote:
John,

my purpose was not to attack you or anyone else participating in this thread - what I said was not meant to be directed at discussion in this thread, rather, at any and all people I've conversed with who stood up to their words with no proof whatsoever, only to be later stood, well, corrected. I am sure you know the type.
My motive is to spark discussion and investigation, not war and flaming - and I do apologize if this was the way you or anyone else might have understood it.

I also originally wrote:
larsr wrote:
I am pretty sure I'm also missing something.



Lars - thanks for your reply. I understand what you are saying and please accept my apologies for directing my rant at you. It might have been better directed at Chris rather than you. However you appeared to support him and one of your posts gave me the opportunity of illustrating how difficult it is to get everything absolutely right.

Look at what Chris said....

ChrisLilley wrote:
Look, people hit these threads through Google. The newer threads tend to come up higher. Some questions (like this one) come up repeatedly, people put in effort to get the accurate information, then it starts again in a new thread with people posting wild guesswork, hearsay, or faulty summarizing and off we go again.


He is, of course, right. But it's the very nature of forums (fora ?) like this one that errors are made. Google collects these errors which are picked up by members of other forums and the errors are propagated, eventually being repeated here.

What's the alternative ? Already we have people prefacing anything they say with AFAIK, IMO, IMHO or some such, for fear of being attacked lest they get it wrong. What now ? Are we going to demand that every statement of fact is clearly indicated as such ? And every statement of fact is provided with a reference ? And what sort of reference ? Presumably only quality references are to be allowed. So no more references to Wikipedia ? I can't speak for the field of photography but in my own field it's half full of sh1t. There's some good stuff as well but you have to be an expert to know which is which - which rather defeats the object of looking there in the first place !

I think that Sven got it right...

Sven wrote:
I can understand your frustration. The truth has been written once, and then new postings tend to distort it.
I can't see how this could be entierly avoided though.
A forum like this will inevitably be populated by people with different areas of skills and knowledge levels. Personally I think that's what makes it interesting.
I realise that it might be annoying for the experts in the forum to continously have to correct the less enlightened ones, but isn't that the whole point, that we learn from each other.
It's a balance really. Tell peolple to avoid posting unless they are 100% certain of all facts and get correct but probably not so many threads. Or, leave it as it is and get many, but sometimes incorrect postings.
I agree that this thread got unusually messy regarding the optical design, bit maybe that's the price to pay for having an open and lively forum.


As for Google ? Well it's a great resource but it a horrible mixture of the good and the bad, the true and the untrue, the relevant and the irrelevant... If you are going to use it, the trick is learning how to. So forums like this one will provide an entry into the field of study/research but in the end you might prefer to rely on primary sources such as Nikon, or Zeiss, or whatever, rather than the content of the forums themselves.


PostPosted: Sun Nov 29, 2009 3:36 am    Post subject: Reply with quote

Guys, this is peer review in action. Brings me back to my college days. I love it. Cool


PostPosted: Sun Nov 29, 2009 4:10 am    Post subject: Reply with quote

cooltouch wrote:
Guys, this is peer review in action.


Yes indeed. So in addition to writing our own submissions we spend our time refereeing other peoples. And if we really want to be respectable we need external referees as well. Maybe the guys at nikongear could help us out with the Nikon stuff, and I'm sure that we could find a Zeiss forum that would be willing to help......


PostPosted: Sun Nov 29, 2009 7:09 am    Post subject: Reply with quote

Hi Aoleg,

Based on the various Sonnar designs you posted, it seems to me that nearly all 3rd party SLR 105mm-180mm I have opened are "Sonnars"

Almost all of them have 4 elements in three groups with a thin front element, very thick cemented #2+3, of strong convex front-concave rear parts, and a rear element.

Many Tamrons, Tokinas, Komine, Sankors, Fujitas, Kyoei, and unknown make lenses all have the same basic design.


PostPosted: Sun Nov 29, 2009 7:33 am    Post subject: Reply with quote

I dont think I have ever read a thread and been more confused.

So simply, I have a Nikkor PC 105 2.5 - 537xxx with a pentax K mount conversion. Which variation is this one?

I only got to use it for some test shots before I had a camera problem... but I liked it. buttery oof area in some situations and fairly sharp wide open. A little flarish... but the hood helped that.


PostPosted: Sun Nov 29, 2009 8:22 am    Post subject: Reply with quote

***I dont think I have ever read a thread and been more confused.***

LOL same here.....for me ignorance is bliss, and what counts is how a lens perfoms in practice, afterall it is the end result that counts in print etc


PostPosted: Sun Nov 29, 2009 8:28 am    Post subject: Reply with quote

luisalegria wrote:
Based on the various Sonnar designs you posted, it seems to me that nearly all 3rd party SLR 105mm-180mm I have opened are "Sonnars"

Almost all of them have 4 elements in three groups with a thin front element, very thick cemented #2+3, of strong convex front-concave rear parts, and a rear element.


Quite many are. However, at least some of them should be classified as Ernostars rather than Sonnars: http://www.taunusreiter.de/Cameras/Biotar.html and http://www.taunusreiter.de/Cameras/Biotar_en.html

http://www.ksmt.com/eos10d/eos_nikki_body36.htm (search for Ernostar to see optical diagrams)



PostPosted: Sun Nov 29, 2009 8:29 am    Post subject: Reply with quote

Gus Helios wrote:
So simply, I have a Nikkor PC 105 2.5 - 537xxx with a pentax K mount conversion. Which variation is this one?


Later Xenotar-type. Multi-coated (that's what 'C' stands for in 'P.C.')