Schneider-Kreuznach Linhof Xenotar 105mm f2.8 - question

[Miltonian]

This lens came with a 6x9 Technika that I bought. I looked it up on the Schneider Historic lens data pages but it's not there!
The 100mm Xenotar is there but not the 105mm.
I have always assumed that the lens data for my 105mm will be exactly the same as for the 100mm but is that correct? It would seem strange to bring out lenses with different focal lengths if the other lens data was exactly the same.
I was quite surprised that Schneider just decided to omit it from the list of Xenotar lenses.
If anyone can help or point me in the right direction I will be grateful.

 

[Ian Grant]

That Schneider lens data isn't exhaustive and doesn't cover all versions of lenses. look here at the Li9nhof brochure its listed.

If it's in excellent condition it might be worth far more than you paid for it

Ian

 

[Miltonian]

That Schneider lens data isn't exhaustive and doesn't cover all versions of lenses. look here at the Li9nhof brochure its listed.

If it's in excellent condition it might be worth far more than you paid for it

Ian

Thanks Ian. I see some ridiculous prices being asked for Xenotar lenses on the auction site. I got 6x9 Linhof IV camera with 4 Linhof selected lenses including the xenotar - all in perfect condition and 3 of them matched to camera via cam- plus 4 backs, grip and metal case for £575. So it was a good purchase! I noticed that a 1950s magazine was offering the 105 xenotar for US$100 extra. Given the date of the ad that converts to about 800$ today so it seems to have been a more expensive lens than the standard offering (Xenar 100?).

 

[shutterfinger]

You can date it here https://www.schneideroptics.com/info/age_of_lenses/

 

[Ian Grant]

Given the date of the ad that converts to about 800$ today so it seems to have been a more expensive lens than the standard offering (Xenar 100?).

There's a 100mm f3.5 Xenar, an f4.5 105mm Xenar liosted by Schneider and an f3.5 105mm Xenar listed by Linhof along with the \f2.7 100mm Planar and f2.8 105mm Xenotar. My 1970 ? (225 IX 70 T e) Schneider Professional Lenses Review leaflet shows the f2.8 100mm Xenotar and also an f4 100mm Xenotar, along with the f3.5 100mm Xenar and f5.6 100mm Symmar.

That Linhof catalogue I linked to shows a choice of 6 Linhof select lenses in the 100mm-105mm range from 3 different manufacturers.

Ian

 

[Miltonian]

On the Butkus manuals site there is a price list from 1962. In that, the 105mm Xenotar is US$128 more than the Xenar (equivalent today about £800 more) but it does not give lens data for it - beyond including it in the "normal" lens category. So the data for it is still a mystery.
Thanks to all so far for comments.

 

[Dan Fromm]

OP, not to be a complete idiot or anything, but what exactly do you want to know about y'r lens?

 

[AgX]

The 100mm lens has a coverage of 116mm and a numerical aperture of 3.5

The 105mm lens has 127mm / 4.5


That's it.

EDIT: I got it wrong. The data is for the Xenar.

 

[Ian Grant]

The 100mm lens has a coverage of 116mm and a numerical aperture of 3.5

The 105mm lens has 127mm / 4.5


That's it.

The OP is asking about the 105mm f2.8 Xenotar, the only info he can find is about the 100mm f2.8 Xenotar.

Presumably the lens was redesigned as newer glasses became available.

Ian

 

[AgX]

Sorry, I was inattentive and negligent, looked without realizing at the wrong chapter, the Xenar, and then for the wrong lens speed...

No, I have no trace of a 105mm 2.8 Xenotar.


I got more stuff in my archive, but that is not accessible in the moment.

 

[Dan Fromm]

AgX, please explain numerical aperture. You're not using the words the way microscopists do. Did you mean relative aperture, i.e., the f/ number?

 

[AgX]

I meant the relative aperture (1/k).

The image-side numerical aperture (A) is 1/2k.



(Keep in mind that we use different terms in Germany.)


And the relative aperture is strictly speaking not the f-number, but 1/f-number.

 

[Miltonian]

Just to be clear, I was interested in the lens data as it normally appears on the Schneider site for most of their lenses - angle of view etc.- but the 105mm f2.8 Xenotar lens does not appear there. Only the 100mm Xenotar.
Again, thanks to all for comments so far.

 

[Dan Fromm]

Same angle of view as the 100/2.8, image circle 5% larger, flange-focal-distance 5% longer will get you very close to reality. Just scale everything up by 5%.

 

[AgX]

As my erroneous post on the Xenar shows, you most probably are right with that 5%.

Basically a improved version may have a relatively larger coverage, but such typically was striven for with lenses that were intended for movements, what the Xenotar is not.

 

[Miltonian]

Postscript - 5% was my guess too but I thought it would be useful to see whether the actual stats on the lens had been published anywhere. Appears not so I sent a nice email to Schneider via their helpful "contact us" tab.
I've come to the conclusion that "contact us" for many companies is equivalent to the old "Suggestions Box" which had a hole in the bottom and a waste paper bin underneath into which the suggestions fell.

 

[locutus]

Wouldn't all these questions be easily answered by mounting it on a 5x4 and measuring off the groundglass etc?....

 

[Ian Grant]

Wouldn't all these questions be easily answered by mounting it on a 5x4 and measuring off the groundglass etc?....

Only partially because illumination is not the same as acceptably sharp coverage. So my 105mm f3.8 Ross Xpres illuminates 5x4 screen fully but it's not an LF lens.

Ian

 

[locutus]

True, a single sheet of film will tell you that part however

 

[itsdoable]

The Xenotar class of lenses from that age all had the same composition (5 elements in 4 groups) and a common angle of illumination (60 deg according to Schneider). Keep in mind that the usual definition of the usable image circle was acceptable resolution at f/16.

The 100 f/2.8 Xenotar had an actual focal length of 101.4mm, a back focus of 75.5, and a 117mm image circle at f/16 (consistent with 60 deg angle of illumination)

Depending on the actual focal length of the 105mm lens, I'm guessing that the image circle is less than 5% larger at f/16.

 

[paul ewins]

Here you go, from the brochure:

 

[Dan Fromm]

Ah! So it covers 4x5 with movements, 5x7 without.

 

[Miltonian]

Excellent! Thanks Paul - and everyone else.

 

[AlanY]

Hello, resurrecting this thread out of interest in this lens.

The image that Paul Ewins posted states that the 105/2.8's image circle is 116 cm in diameter. This is considerably under the 153 cm needed for 4x5. Why did Dan Fromm say that it "covers 4x5 with movements"?

 

[Dan Fromm]

Fair question. I don't remember, was probably being sarcastic and didn't turn on the sarcasm indicator.