Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

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enricosavazzi
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Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by enricosavazzi »

I published on my web site a set of tests of the Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9.

http://savazzi.net/photography/xenoplan32.html

Unless I am mistaken, the stacked lenses at 7.5x, with a working distance of 13 mm and a front element diameter of 14.5 mm, have NA 0.487, more than twice the Mitutoyo M Plan Apo 7.5x (0.21).
--ES

dickb
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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by dickb »

Very interesting to read this. A few remarks:
enricosavazzi wrote:
Mon Apr 25, 2022 6:25 am
Its recommended price online varies between 676 € and 820 € plus sales tax, but used specimens sell for as little as 22 € because these lenses are poorly known and not "fashionable" on the second-hand market. My specimen has a long and fine-pitched thread at the rear of the barrel that fits a lockable focusing mount ending in a C thread, and lacks a variable aperture.
Yours is that cheap because of the fixed aperture. Those with a regular variable aperture tend to sell for a bit over a 100 €. Removing the aperture is sometimes possible but not that easy, as discussed here:viewtopic.php?p=254317&sid=0e6d59019092 ... 9a0ebe34a9
There is no new name for my particular lens version with fixed aperture, which may therefore be discontinued or only available on special order. All the present models of this lens have an aperture ring. I found no magnification data for my version in Schneider literature, but a Schneider sticker on the lens barrel says 1:4.0, i.e. 0.25x. This is obviously inconsistent with the 0-0.1x magnification range specified for current models of this lens, which is another reason suggesting that my lens specimen is a special-order item.
The 1:4.0 is not the suggested magnification. It is the aperture, which in your version is a fixed disc corresponding to f/4.0. Schneider has a few lenses with special fixed aperture versions, I know of the Cinegon 1.4/8 (1:2.0), there is an f/5.6 version of the Apo Componon 50mm and some similar ones taken out of scanners.
The three currently available models differ only in mechanical specifications (C-mount with manual aperture, ruggedized C-mount, and C-mount with motorized iris).
One different model of the compact series you're describing here is the 1.4/23-0502. This one doesn't have filter threads, but a sturdier front barrel, better suited for clamp-on filters. Any lens from the Compact Series that has a code starting 05xx lacks a filter thread, those with 09xx (like your 0912) do have one. The regular aperture version is called 0902.

I'm not sure whether this model is currently available new, but there are also versions sold as CCTV lenses, with built-in helicoids, fixed C-mounts and larger diameter filter threads.
Removing the reversing adapters and manually holding the Xenoplan lens as close as possible to the Makro-Symmar reduces the amount of vignetting, compared to mounting on the adapters. The corners still darken to a moderately higher extent than after removing the Xenoplan. Thus, the Xenoplan still has an effect on vignetting, albeit less than with a long adapter. It may be possible to cut off the front 5 to 10 mm of the lens barrel to place the two lenses even closer together, but for the moment I will not go that far.
One way of getting the two lenses closer together is by using the C-mount instead of the filter thread. The lens fits inside an M42 helicoid, so you can use a C-mount-M42 adapter, M42 helicoid and M42 to whatever the filter thread of the tube lens is. For most lenses this means you can't adjust the aperture anymore, but with this one you can't anyway.

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by rjlittlefield »

enricosavazzi wrote:
Mon Apr 25, 2022 6:25 am
Unless I am mistaken, the stacked lenses at 7.5x, with a working distance of 13 mm and a front element diameter of 14.5 mm, have NA 0.487, more than twice the Mitutoyo M Plan Apo 7.5x (0.21).
That value for NA strikes me as somewhat too large. A simple and accurate estimate for the case where the rear lens is focused at infinity, with a reversed f/1.4 on the front, is to calculate as 1/(2*1.4) = NA 0.357, using the formula that NA = 1/(2*fnumber). In your 7.5X setup, which adds some extension, the lens and thus its pupil move a little closer to the subject, which increases the NA. However, the reduction in lens-to-subject distance is listed as only 4 mm (from 17mm down to 13 mm). We do not know the exact position of the pupil, but given a pupil ratio >2, it must be significantly farther than 1 focal length away from the focus point. If we guess that it is located at 32 mm (=FL*sqrt(2)), then reducing the working distance by 4 mm will increase the NA by a ratio of about 32/28, which would bring NA up to 0.41.

So, I think the correct NA is not as large as your number, but I agree it should be significantly larger than the Mitutoyo. Putting the Mitutoyo in perspective, if reversed and used for landscape photography it would be 26.7 mm FL (=200/7.5) and f/2.38 (=1/(2*0.21)).

--Rik

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by Lou Jost »

In addition, as Dick said, your front lens is actually set to f/4. Check to see if it has a disc inside it acting as a fixed stop. I have one of these lenses, seemingly the same model, and mine has an obvious disc.

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by rjlittlefield »

f/1.4 versus f/4.0 for the Xenoplan 23 mm should be easily determined by measuring the pupil from the side away from the C-mount, that is, the normal "front" of the lens. f/1.4 will have a nominal 16.4 mm pupil; f/4 will have only 5.75 mm.

--Rik

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by enricosavazzi »

rjlittlefield wrote:
Mon Apr 25, 2022 5:04 pm
f/1.4 versus f/4.0 for the Xenoplan 23 mm should be easily determined by measuring the pupil from the side away from the C-mount, that is, the normal "front" of the lens. f/1.4 will have a nominal 16.4 mm pupil; f/4 will have only 5.75 mm.

--Rik
Good idea, in my case I measured the front pupil (through the front of the lens) as roughly 8.3 mm. So apparently neither f/1.4 nor f/4, but close to f/2.8.
Xenoplan_front_pupil_s.jpg
Added:
From the pupil ratio of 2.27 in the Schneider specifications, we can compute 2.27 * 8.3 = 18.8 diameter of the rear pupil.
By slightly inclining the lens diagonally, I was able to measure the approximate optical distance of the rear pupil from the rear lens element: 38 mm, adjusted to 35 mm to correct for the oblique inclination of the measurement. This is more than I estimated "by eye".
So we have a rear pupil with a diameter of 18.8 mm at an optical distance of 35 mm + 13 mm (= working distance at 7.5x) from the subject. The angle of the cone of light allowed by the rear pupil is approximately 22ͦ, considerably less than the 58ͦ allowed by the rear element, so NA, based on this 22ͦ , becomes sin(22/2)=0.19, actually slightly less than the Mitutoyo M Plan Apo 7.5x (0.21). Still a respectable result, although not as high as I initially believed.

I may have made unwarranted assumptions (for example the "plane" of the real pupil is a spherical surface, not flat), but this is what I was able to do so far.
--ES

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by RobertOToole »

Hi Enrico,

I've tested most of the small format XNP SK lenses stacked incl. the XNP 1.4/23. Some of the results have been posted in tests on my site. I intended to create a web page for some of the best XNP lenses, like the APO-Xenonplan 1.8/35, but I changed my mind due to the poor coverage (I have a drawer with 4 or 5 or 6 XNPs if anyone is interested in them, they are listed for sale on the buy and sell forum).

The XNPs are made for tiny sensors as you mention. The Xenon and Componon are designed for slightly larger coverage which means they wont match the XNP or APO-XNP in the center area but they beat them in the APS-C and FF corners. (you can see the results of the APO-XNP 1.8/35 stacked here: https://www.closeuphotography.com/35mm-lens-test and here: https://www.closeuphotography.com/three ... -lens-test where it is stacked on the Makro-Symmar 120)
That said the XNP coverage does get better up at higher mags but a Componon 28 or 35 will always beat it in corners.

FYI SK loves to re-badge lenses. On my site I mention this a few times, one good example is the 2.8/50 Componon-s. Its sold/badged as a CNP-S, also a Xenoplan, also an APO-Xenoplan all with the same exact optical layout, and I'm pretty sure the APO-XNP 1.4/23 is the same lens as the XNP 1.4/23 for a few reasons. The APO- prefix was just added by the sales department.

I can add some notes and info in reference to your test I don't want to clutter your thread so I wont post them here. Maybe you can let me know.

Best,

Robert

dickb
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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by dickb »

RobertOToole wrote:
Wed Apr 27, 2022 6:50 pm
The XNPs are made for tiny sensors as you mention. The Xenon and Componon are designed for slightly larger coverage which means they wont match the XNP or APO-XNP in the center area but they beat them in the APS-C and FF corners. (you can see the results of the APO-XNP 1.8/35 stacked here: https://www.closeuphotography.com/35mm-lens-test and here: https://www.closeuphotography.com/three ... -lens-test where it is stacked on the Makro-Symmar 120)
That said the XNP coverage does get better up at higher mags but a Componon 28 or 35 will always beat it in corners.


Not all Xenoplan and Apo Xenoplan lenses are designed for equally tiny sensors. Some are listed as anti-shading and have a much larger IC. The Xenoplan 28/2.0, Apo Xenoplan 20/2.0 and Apo Xenoplan 35/2.0 for instance.

If a lens has so-called poor coverage when stacked then my conclusion is that the tube lens is too short for optimal results. As you say XNP coverage increases with higher magnifications, and there must be a magnification where the XNP starts to outperform the Componons even in the corners.
FYI SK loves to re-badge lenses. On my site I mention this a few times, one good example is the 2.8/50 Componon-s. Its sold/badged as a CNP-S, also a Xenoplan, also an APO-Xenoplan all with the same exact optical layout, and I'm pretty sure the APO-XNP 1.4/23 is the same lens as the XNP 1.4/23 for a few reasons. The APO- prefix was just added by the sales department.
I agree that there are many Schneider lenses with different badges with the same optical schemes. I disagree about the APO-XNP 1.4/23 and the XNP 1.4/23 being one of them. They are extremely similar, but slightly different. The apo 23mm is one of the few Xenoplans I don't own, so I can't test the two against each other. I doubt there will be a big difference in IQ.

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by RobertOToole »

dickb wrote:
Fri Apr 29, 2022 3:01 am
I agree that there are many Schneider lenses with different badges with the same optical schemes. I disagree about the APO-XNP 1.4/23 and the XNP 1.4/23 being one of them. They are extremely similar, but slightly different. The apo 23mm is one of the few Xenoplans I don't own, so I can't test the two against each other. I doubt there will be a big difference in IQ.
Hi Dick,

My conspiracy theory, that the APO-XNP 1.4/23 is really an plain XNP 1.4/23 with the APO added, is just a feeling I have, but its been awhile since I've looked into it so I could of course be completely wrong! #-o

I'll search in my drive to see if I have any more info.

I'm just glad to see people interested in this subject. I think the XNPs are fantastic little lenses.

Best,

Robert

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by RobertOToole »

dickb wrote:
Fri Apr 29, 2022 3:01 am
I agree that there are many Schneider lenses with different badges with the same optical schemes. I disagree about the APO-XNP 1.4/23 and the XNP 1.4/23 being one of them. They are extremely similar, but slightly different. The apo 23mm is one of the few Xenoplans I don't own, so I can't test the two against each other. I doubt there will be a big difference in IQ.
Hi Dick,

Thanks for giving me an excuse to dig up some details Dick. I completely forgot about this stuff #-o

Searched my drive and found a couple of interesting things. This was gathered years ago as I planned to spend time on pages covering APO-XNP line but changed plans (the Fujinon EFC page was also cancelled) before I posted anything.

This is what the XNP and APO-XNP lenses look like for scale with an overlay of the optical layout. I scaled the diagrams to size using the C-mount. The optical layouts are scaled to match using the front and rear element positions. Ignore the APO-XNP 35mm (The APO-XNP 35mm is included since this was the first lens to get its own page, that was the plan anyway).


_SK-XNP-www-closeuphotography-com.jpg


This is interesting! They look identical except for the added flat looking element at the rear.

Now look at the MTFs, XNP vs APO-XNP. The normal XNP looks a lot better until you take a look at the graphed frequencies in l/mm. The APO version is on a completely different range although its very nice that all the other parameters of the test are the same like wavelength weighting.


_xnp-vs-APO-XNP-MTF-www-closeuphotography-com.jpg


Now that we know this just compare the curve marked with a red arrow on the XNP to the curve on the APO XNP, also with arrow, they are really close! This is also really interesting! Forgot about this one also! #-o


_xnp-vs-APO-XNP-23-www-closeuphotography-com.jpg



My hunch about the APO-XNP 1.4/23 really being a plain renamed XNP 1.4/23 was wrong. This data shows they are different designs with the APO version has one tiny flat cover glass added at the rear being the biggest difference. Technically it is a new and different design. But is there any effect in image quality? The MTF data looks very similar. In any case I don't think the single element + tweaks made to the XNP turn it into a APO design on the same level of a Makro-Symmar, but technically legally Schneider can claim the design is different no doubt.

Best,

Robert
Last edited by RobertOToole on Fri Apr 29, 2022 8:06 pm, edited 2 times in total.

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by RobertOToole »

dickb wrote:
Fri Apr 29, 2022 3:01 am

Not all Xenoplan and Apo Xenoplan lenses are designed for equally tiny sensors. Some are listed as anti-shading and have a much larger IC. The Xenoplan 28/2.0, Apo Xenoplan 20/2.0 and Apo Xenoplan 35/2.0 for instance.
Yes, true, that said the APO-XNP Anti-Shading are marketed as a higher end range, above and beyond the normal XNPs.

Compact C-Mount Lens
Optimized for Sony 5 Mega Pixel Sensor: 2/3" format
3.45μm pixel size
• Compact design
• Optimized at 400-1000 nm
• VIS and NIR corrections
• Long-term stable locking for focus and aperture



_SK-Compact-lenses.jpg




This is interesting:
Optimized for Sony ICX 625 (5 MP) sensor
Pixels: 2456 ×2058
Pixel Size: 3.45μ ×3.45μ
Sensor Diagonal: 11,0mm
Nyquist Frequency: 145lp/mm
2/3 Nyquist: 97 lp/mm
30% MTF at lens image circles 11mm and 97lp/mm corresponding to this sensor is required.


Note: The inconsistent data from SK makes interesting reading at least. Which is it, 3.45 μm, 2.5 or 1.65 for the APO-XNP 1.8/35? (I've seen all these figures quoted in SK docs)





Anti-Shading
Schneider-Kreuznach series for sensors with microlenses.




_SK-AS-lenses.jpg


Optimized for Kodak 4MP and 8MP sensors with microlenses
telecentric on the image side
Image Circle: 22mm diagonal

• C-mount
• Image circle 24mm
• Optimized for CCDs with microlenses
• Designed for Kodak 4 MP and 8 MP sensors
• Wavelength range 400 - 1000nm
• Very high image performance
• Compact and robust design




_XNP-IC-comp.jpg





I could keep going but I'll stop dumping info here as to not drag the thread away from the OP any further. :-k {-X


Best,

Robert

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by rjlittlefield »

RobertOToole wrote:
Fri Apr 29, 2022 6:06 pm
with the APO version has one tiny flat cover glass added at the rear being the biggest difference. Technically it is a new and different design. But is there any effect in image quality? The MTF data looks very similar.
I have to disagree.

When I pull the lens diagrams into Photoshop and layer one over the other, what I see is that every lens element has a different shape between the APO and non-APO versions. The single flat element is the big architectural difference, but either these lenses are optimized differently or the diagrams are oddly sloppy.

Here is the comparison animated:
XenoplanApoDesignComparison.gif

As for performance, the graphs are not so easy to overlay, but as far as I can see by spot-checking values, away from center the APO gives about the same performance at 50 l/mm that the non-APO gives at 30, most obvious on the "tangential" curves stopped at f/4 and f/8.

--Rik

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by RobertOToole »

rjlittlefield wrote:
Fri Apr 29, 2022 8:47 pm
RobertOToole wrote:
Fri Apr 29, 2022 6:06 pm
with the APO version has one tiny flat cover glass added at the rear being the biggest difference. Technically it is a new and different design. But is there any effect in image quality? The MTF data looks very similar.
I have to disagree.

When I pull the lens diagrams into Photoshop and layer one over the other, what I see is that every lens element has a different shape between the APO and non-APO versions. The single flat element is the big architectural difference, but either these lenses are optimized differently or the diagrams are oddly sloppy.

Here is the comparison animated:

XenoplanApoDesignComparison.gif


As for performance, the graphs are not so easy to overlay, but as far as I can see by spot-checking values, away from center the APO gives about the same performance at 50 l/mm that the non-APO gives at 30, most obvious on the "tangential" curves stopped at f/4 and f/8.

--Rik
Hi Rik,

Nice observation. I might be to blame for some part of the differences, I had to scale the two drawings to match and I used PS using the transform command + preserve scale.

One thing I can add. I don't know how much credit I would give to the art department at Schneider for accuracy since they didn't even bother to add the APO designation to the APO-XNP drawing, even when they updated to new style lens data sheets. So they let it go and used the old standard XNP version illustration, twice. The other APO lenses I checked, are labeled APO in the drawings. #-o

Best,

Robert
Last edited by RobertOToole on Sat Apr 30, 2022 1:47 am, edited 1 time in total.

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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by RobertOToole »

MTF with XNP left column and flipped so center is at the same point as the APO-XNP on the right side.
(other freq curves have been masked out in PS)


_Std-vs-apo-mtf.jpg

dickb
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Re: Schneider Xenoplan 23 mm f/1.4 stacked on Schneider Makro-Symmar 120 mm f/5.9

Post by dickb »

RobertOToole wrote:
Sat Apr 30, 2022 12:22 am
One thing I can add. I don't know how much credit I would give to the art department at Schneider for accuracy since they didn't even bother to add the APO designation to the APO-XNP drawing, even when they updated to new style lens data sheets. So they let it go and used the old standard XNP version illustration, twice. The other APO lenses I checked, are labeled APO in the drawings. #-o
I've noticed a fair number of inconsistencies in their drawings as well. BTW, they did adapt the APO XNP 1.4/23 drawing, it has the longer C mount focussing adapter compared to the regular XNP 1.4/23.
Yes, true, that said the APO-XNP Anti-Shading are marketed as a higher end range, above and beyond the normal XNPs.
I'd say the APO-XNP series are marketed as higher end over the normal XNP, irrespective of them being Anti-Shading or not. The 2.0/28 I mentioned before is a non-APO Anti-Shading XNP..

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