APO-Ronar vs. APO-Ronar-CL ??

[Harley Goldman]

What is the difference between the APO-Ronar and the APO-Ronar-CL lens? Is the latter suitable for landscape photography? I assume the APO-Ronar is, as it is current sold by various camera stores.

I am looking for a lightweight 360mm lens and the G-Claron is a little bigger than I would like, so I have been researching the Rodenstock line. I understand the Fujinon-A is a candidate, but is extremely hard to find (per the info at Kerry Thalmann's website).

[CP Goerz]

The CL Ronar uses a special compound to hold the elements in alignment through extremes of temperature. When manufacturers changed from brass to aluminum to make lens mounts/barrels they found/already knew that aluminum expanded/contracted more than brass did and most just allowed a little more slop to cover. Rodenstock made this compound to ensure that the elements stayed in the factory set positions. A chap in the process lens recalibration/repair field told me that little snippet and he often bemoans aluminum barreled lenses as being inferior to brass ones.He's one of the top dogs in that biz so tend to take his information without any salt.



CP Goerz

[Bob Salomon]

Linearized aperture scale vs non linearized aperture scale. Both are corrected for 1:1 of 2 dimensional art. Neither is corrected for landscapes.

[CP Goerz]

PS:I sold a 360 Fuji on Ebay a few months ago, nice lens. Have you thought of a Red Dot Artar instead? They are small, coated, often in shutters, and very sharp.

CP Goerz

[Arne Croell]

CP Goerz is correct about the CL. My (German) Rodenstock brochure on their process lenses (late 1980's) states that instead of the usual mechanical mounting the CL lenses are first centered/oriented in the mount using autocollimation (an optical method for centering) and are then permanently fixed in that position by injection of some plastic. According to Rodenstock this reduces stress-induced birefringence of the glass and reduces the variation of the MTF in production from 0.1 down to 0.05.
Although the Apo-Ronars are not optimized for infinity, they (as well as the similar Apo-Artars, Apo-Germinars, and Apo-Nikkors) hold their corrections well at infinity. MTF graphs for a 240mm Apo-Ronar at infinity (as well as 1:1) can be found here: http://www.butzi.net/rodenstock/apo-ronar/p12.htm

[Harley Goldman]

Are these lenses multi-coated? Single coated? Based on what has been said, I would assume that for landscape work, there would be no functional difference between the CL and non-CL versions?

[Arne Croell]

Late Apo-Ronars sold in shutter are multicoated (either marked MC on the front lens cell or with a blue ring around it), the barrel process lens versions are usually single coated. However, I have used a 300mm multicoated Apo-Ronars and a single coated 300mm Apo-Germinar and have not seen any significant difference.

[Bob Salomon]

"My (German) Rodenstock brochure on their process lenses (late 1980's)"

Unfortuantely I have the latest Process Lens brochure from Rodenstock (3/94) in which they state only:

" The Apo-Ronar CL is primarily used in horizontal and vertical cameras. The closely spaced focal lengths range from 150 to 1800mm. ALL APO-RONAR CL LENSES HAVE LINEAR APERATURE SCALES - EXCEPT FOR THE 150MM LENS. (WHICH DOES NOT CARRY THE CL SUFFIX AND HAS NO LINEAR APERTURE SCALE). The angle of field is 48° for lenses up to and including 480mm, above that it is 40 - 46°. Most Apo-Ronar CL lenses are 4 element systems. For specially demanding jobs, for instance map making, Rodenstock has also developed six element versions of 600, 800 and 1200mm. A slot in the lens mount takes filter holders.

In the older (6/82) Process Lens brochure Rodenstock does describe the special centering process and the delicacy required to center Apo Ronar lenses. It then goes on to state:

"As already mentioned, the Apo-Ronar system is somewhat delicate when it comes to centering, which is why IT BENEFITS FROM THE SPECIAL CASTING-IN PROCESS RODENSTOCK DEVELOPED FOR THIS PURPOSE.

That refers to all Apo-Ronar designs - the Apo Ronar, the Apo Ronar CL, the Apo Ronar M, the F Theta Ronar, etc.

The difference between the Apo Ronar in NF mount and the Apo Ronar CL in NF mount is the linearized aperture scale on the CL. The CL was not multi coated.

All Apo Ronar lenses are no longer made.

[Arne Croell]

Bob, the CL's certainly do have the linear scale which sets them apart from the normal ones as you stated. As for the centering I have the German brochure (also printed 1982, I just got it in the late eighties) in front of me. It says under the heading "A New Type of Mounting" ("Eine neue Art der Montage"): "In the Apo-Ronar series named "CL" the lenses are centered in the mount by autocollimation and are then fixed in the mount with a suitable plastic" ("In der mit "CL" bezeichneten Serie der APO-RONARE werden die Linsen mit Hilfe des Autokollimationsverfahrens in der Fassung ausgerichtet und dann mit einem geeigneten Kunststoff formschlüssig in die Fassung eingegossen"). In another section on that page under the heading "Apo-Ronar/Apo-Ronar CL" Rodenstock writes first about the Apo-Ronars in general, then about the normal nonlinear aperture scale, and then about the advantages of the linear scale, saying about the latter: "There the angle from one aperture to the next is constant. Therefore a second series of Apo-Ronars is delivered with linearized aperture. These are also the lenses mounted with the new method. ("Da ist der Drehwinkel von einer Blendenstufe zur anderen konstant. Eine zweite Reihe von Apo-Ronaren wird deshalb mit linearisierter Blende geliefert. Das sind zugleich die Objektive, die nach dem neuen Verfahren montiert sind"). From this text I conclude that only the CL version uses that centering method - at least at the time of printing of this brochure. Later things may have changed of course. [Translations are mine; original German quotes in parentheses]

[Bob Salomon]

"NF mount is the linearized aperture scale on the CL" Arne,

That is what I did say. The CL had a linearized mount the Apo Ronar in NF mount did not.

In shutter the Apo Ronar could have the linearized scale. This only applies to them in NF mount.

Yes the CL had the special centering. But that changed over time and all Apo Ronars were made that way. You are looking at a 21 year old brochure. Mine is a decade newer.

[Tin Can]

Here's an old thread that does not ever answer OP's question and I now have the same question.

I find almost nothing about APO-Ronar-CL lens.

I 'thought' I remembered reading that CL Ronar was wider angle than a plain Ronar. I am looking for coverage or angle de vista.

I cannot find that info anywhere.

Any ideas or links?

[Dan Fromm]

Randy, read the thread from the beginning, you missed all this: the Apo-Ronar CL is an Apo-Ronar with a linear aperture scale and elements cemented in the barrel. Otherwise the same lens.

For Rodenstock's coverage claims see http://1drv.ms/12OFqc2

[Tin Can]

Dan, I did read it. Twice

So you are saying it's the mount that is different, not any other feature?

Nothing here, http://en.wikipedia.org/wiki/Rodenstock_GmbH#APO-Ronar-CL

or here which seems odd as isn't the CL a more modern and corrective mount? http://www.bhphotovideo.com/FrameWork/Product_Resources/SourceBookProPhoto/Section04LgFormatLenses.pdf

I need a little more than same same, if possible.

Thanks Dan.

Link read, so it is same same.

[Dan Fromm]

Randy, CL's lens elements are glued in, plain Apo Ronar's lens elements are held in place by retaining rings.

The complete lenses have the same mount threadings, except the ones that don't.

Re the ones that don't, Apo Ronars made for some process camera manufacturers, e.g., Klimsch, were delivered in barrels whose mount threads didn't match those of equivalent lenses made for all comers. Bob Salomon, who knows, has said many times that there's no guarantee that Klimsch Apo Ronars have the same optimizations as ones made for all comers. On the other hand, there's also no guarantee that they have different optimizations. No one really knows which is the case, both are possible.

[Tin Can]

Thanks!

I have one coming in the mail.

[angusparker]

CL tend to have higher max aperture like f14 and be smaller and lighter. Really great choice for 760mm for example when compared to alternative options.

[Tin Can]

CL tend to have higher max aperture like f14 and be smaller and lighter. Really great choice for 760mm for example when compared to alternative options.

That's news I can use.

Thanks

[Dan Fromm]

Angus, f/14 is smaller than f/9.

Randy, read the catalog. Much of the information posted on bulletin boards just ain't so.

What you don't know will hurt you less than what you think you know that ain't so.

[angusparker]

Angus, f/14 is smaller than f/9.

Randy, read the catalog. Much of the information posted on bulletin boards just ain't so.

What you don't know will hurt you less than what you think you know that ain't so.

Yeah I know. I meant smaller I guess.

[europanorama]

1. What is NF-mount?
2. elsewhere bob meantioned if apo-ronar is in shutter then aperture increased from f9 to f11 fully open.
e.g. glennviews apo-ronar 480 f11 on novoflex D-system which has his own aperture no shutter. is glenn right?
3. Coating:
When its MC or has blue ring then ist multicoating, better for colorshooting.
I remember Zeiss Sonnars 180 and 300mm where is said non-MCs are better for b+w. the same for Apo-Ronars? Film only of course.

[plaubel]

Linearized aperture scale vs non linearized aperture scale. Both are corrected for 1:1 of 2 dimensional art. Neither is corrected for landscapes.

Hello, Bob,

years ago, a wise man from Rodenstock Germany, I forgot his name, sorry, told us, that if my 480er Apo Ronar sits in a shutter, it is corrected for ininity.
Rodenstock created this difference to non shutter Apo Ronars by using / not using a kind of spacer, and one can do this job alone, at home.

Ritchie

[Bob Salomon]

Hello, Bob,

years ago, a wise man from Rodenstock Germany, I forgot his name, sorry, told us, that if my 480er Apo Ronar sits in a shutter, it is corrected for ininity.
Rodenstock created this difference to non shutter Apo Ronars by using / not using a kind of spacer, and one can do this job alone, at home.

Ritchie

Ritchie, the spec sheets showed them corrected for 1:1 in or out of shutter.

[plaubel]

I know, 1:1 was the original concept, but Rodenstock gave a second possibilty, too.
In germany, the thing with the spacer is well known to some photographers.

If you open your Ronar (480, the others I don't know), you can see by looking at the spacer, or the missing spacer, which correction is given.
As said before,this was an official tale from Rodenstock to customer.

Do you know the name of the last old man with experience in older lenses, who worked at Rodenstock? I can't remember, sorry, it may be 10 or 15 years ago..

Wait a minute - there is a german astronomic forum, where another ex-specialist from Rodenstock gave great informations about the Ronars, too, and in my memories, he has said the same.
If you want to know more, we can do a timerobbing research, because I don't know the name of the forum anymore nor the name of the thread, but it had something to do with - Ronars.
During searching informations around my not so often 520er Apo Ronar, I had found this thread...

Ritchie

[Bob Salomon]

I know, 1:1 was the original concept, but Rodenstock gave a second possibilty, too.
In germany, the thing with the spacer is well known to some photographers.

If you open your Ronar (480, the others I don't know), you can see by looking at the spacer, or the missing spacer, which correction is given.
As said before,this was an official tale from Rodenstock to customer.

Do you know the name of the last old man with experience in older lenses, who worked at Rodenstock? I can't remember, sorry, it may be 10 or 15 years ago..

Wait a minute - there is a german astronomic forum, where another ex-specialist from Rodenstock gave great informations about the Ronars, too, and in my memories, he has said the same.
If you want to know more, we can do a timerobbing research, because I don't know the name of the forum anymore nor the name of the thread, but it had something to do with - Ronars.
During searching informations around my not so often 520er Apo Ronar, I had found this thread...

Ritchie
I was the Rodenstock Product and Sales Manager in the US and all the information that the factory gave us was for 1:1. In and out of shutter. Think about it a minute. When the factory put the lens into a shutter at the factory they had no way of knowing if it would be used by the eventual consumer for 1:1 or for infinity.

[plaubel]

Great luck, Bob, after some minutes i found the information !

http://forum.astronomie.de/phpapps/ubbthreads/ubbthreads.php/topics/144448/Apo_Rodagon_Reprobjektive_fur_

No 747, from Mr. Walter E. Schön, who has had to do at thistime, anno 2004, with the technical documentation around Rodenstock lense.

In translation, he described , why an Apo Ronar, constructed for 1:1, not depend so much on given ratio - because of the thin lenses, the symmetrical concept and big "Krümmungs radius". This must mean the radius of the "convex"..

He also explained, that the ApoRonars from 150 to 480mm came in barrels, but also in shutters.
In this case, the space between lense were changed with a tiny factor.

And i know, that this factor is given by thin shims.
This, I haven't forget :-)

Ritchie

[Bob Salomon]

Great luck, Bob, after some minutes i found the information !

http://forum.astronomie.de/phpapps/ubbthreads/ubbthreads.php/topics/144448/Apo_Rodagon_Reprobjektive_fur_

No 747, from Mr. Walter E. Schön, who has had to do at thistime, anno 2004, with the technical documentation around Rodenstock lense.

In translation, he described , why an Apo Ronar, constructed for 1:1, not depend so much on given ratio - because of the thin lenses, the symmetrical concept and big "Krümmungs radius". This must mean the radius of the "convex"..

He also explained, that the ApoRonars from 150 to 480mm came in barrels, but also in shutters.
In this case, the space between lense were changed with a tiny factor.

And i know, that this factor is given by thin shims.
This, I haven't forget :-)

Ritchie

Walter is a good friend and he is Dr, not Mr. Among other things he designed the Rodenstock Scheimpflug/DOF calculator and wrote many white papers for Rodenstock. But the lens is still not designed for general infinity shooting and will be inferior to an Apo Sironar - or S. In addition the Apo Ronar is corrected for f22 only where as the Sironar designs, besides having far greater coverage, also have a greater range for optimal aperture.

[plaubel]

""When the factory put the lens into a shutter at the factory they had no way of knowing if it would be used by the eventual consumer for 1:1 or for infinity. ""

I have heard two same opinions from two different Rodenstock workers, and yes, I know from the forum about your great Rodenstock job.

I know one guy, who has bought the last Apo Ronar 480mm from Rodenstock after stopping the production, and during buying the lens, he has had some interesting small talks with the Rodenstock man. So he got the information about the ratio and the spacers this way.

Maybe Rodenstock in germany asked the customer in general for the task of the lens and the need of the shims, or maybe Rodenstock decided by themselves to build in a spacer. I don't know; reading Dr. Schön, it seems, that Rodenstock made this atomatically.
But they really did, and there exist two versions, one constructed and corrected for 1:1, and one secondway-corrected for infinity.

Ritchie

[8x10 user]

There is a Sinar version of the CL that can be taken apart where one will find two shims. It seems to make sense that removing one of these would adjust the optimization.

[Bob Salomon]

""When the factory put the lens into a shutter at the factory they had no way of knowing if it would be used by the eventual consumer for 1:1 or for infinity. ""

I have heard two same opinions from two different Rodenstock workers, and yes, I know from the forum about your great Rodenstock job.

I know one guy, who has bought the last Apo Ronar 480mm from Rodenstock after stopping the production, and during buying the lens, he has had some interesting small talks with the Rodenstock man. So he got the information about the ratio and the spacers this way.

Maybe Rodenstock in germany asked the customer in general for the task of the lens and the need of the shims, or maybe Rodenstock decided by themselves to build in a spacer. I don't know; reading Dr. Schön, it seems, that Rodenstock made this atomatically.
But they really did, and there exist two versions, one constructed and corrected for 1:1, and one secondway-corrected for infinity.

Ritchie

We were the Rodenstock distributor for the photographic industry in the USA and, as such, only sold Apo Ronar lenses factory mounted in shutters. For the graphic arts industry the Apo Ronars in barrel mount were imported and distributed by, first, Rodenstock USA and then later by Linos after Linos bought Rodenstock Precision Optical. In all literature and discussions that we had with the factory, from our becoming the Rodenstock distributor in 1986 till the end of the production the lenses we were told that they were all designed for 1:1 but that they were useable at infinity but would not perform as well as the Sironar-N, Apo Sironar-S, or Apo Sironar series lenses. We also know, from both spec sheets and working with major studios for advertising photos of fine products that they also did not equal the Makro and Apo Macro Sironar lenses for product work. However they were far better then either for copy work.

[Dan Fromm]

How many shims can dance on the head of a pin?

[Bob Salomon]

1. What is NF-mount?
2. elsewhere bob meantioned if apo-ronar is in shutter then aperture increased from f9 to f11 fully open.
e.g. glennviews apo-ronar 480 f11 on novoflex D-system which has his own aperture no shutter. is glenn right?
3. Coating:
When its MC or has blue ring then ist multicoating, better for colorshooting.
I remember Zeiss Sonnars 180 and 300mm where is said non-MCs are better for b+w. the same for Apo-Ronars? Film only of course.

1 NF is barrel mount
2 with some lenses the opening of the aperture in the shutter is smaller then the useable diameter of the lens. In those cases the maximum aperture of the lens is slower then the same lens in NF mount. It is a physical thing. Not an optical thing.
3 They are all coated. Any Rodenstock lens marked MC on the rim is multi coated. If it is not marked MC then it has standard coatings. There is no mention in Rodenstock lens brochures that the Apo Ronars are multi coated and, considering that they are process lenses, there would not be much of a reason for them to be MC since repro work has very controlled lighting so MC would not be required.

[TML74]

Just to say that I have a long Apo ronar CL mounted on a sinar copal shutter, without any modification on the lens itself (as far as I know) and it gives razor sharp images for landscape...
Emmanuel Biggler on the french forum "galerie photo" is fond of theese lenses.

143325

143326

Quick scan with a bad scan (epson 4870) of part of an 8x10 slide.
Taken from San Giorggio Maggiore, so at a distance of about, let's say 500 m, so I think we can talk about infinity...

Hope that it can help...

Thierry M.L.

[Bob Salomon]

Great luck, Bob, after some minutes i found the information !

http://forum.astronomie.de/phpapps/ubbthreads/ubbthreads.php/topics/144448/Apo_Rodagon_Reprobjektive_fur_

No 747, from Mr. Walter E. Schön, who has had to do at thistime, anno 2004, with the technical documentation around Rodenstock lense.

In translation, he described , why an Apo Ronar, constructed for 1:1, not depend so much on given ratio - because of the thin lenses, the symmetrical concept and big "Krümmungs radius". This must mean the radius of the "convex"..

He also explained, that the ApoRonars from 150 to 480mm came in barrels, but also in shutters.
In this case, the space between lense were changed with a tiny factor.

And i know, that this factor is given by thin shims.
This, I haven't forget :-)

Ritchie

Actually the factory states that the Apo Ronars are optimized for 1:1 but since they are symmetrical designs that they work out to infinity and would out perform most Tele designs. But the will not equal the N or S or W Sironars at those ratios.

[plaubel]

Actually the factory states that the Apo Ronars are optimized for 1:1 but since they are symmetrical designs that they work out to infinity and would out perform most Tele designs. But the will not equal the N or S or W Sironars at those ratios.

Of course, this is the main information. Primary, it is a Repro lens.
To know, if the correction by shims is given or not, may be important too, to somebody..
And for me, personally, my 480er Ronar is my sharpest lens for normal distances, it is surprising sharp on 5x7".
Macro doesn't make sens to me with a 480mm lens, so I havn't any experience.

Thanks for the discussion,
Ritchie

[Bob Salomon]

Of course, this is the main information. Primary, it is a Repro lens.
To know, if the correction by shims is given or not, may be important too, to somebody..
And for me, personally, my 480er Ronar is my sharpest lens for normal distances, it is surprising sharp on 5x7".
Macro doesn't make sens to me with a 480mm lens, so I havn't any experience.

Thanks for the discussion,
Ritchie

I do. We sold Dixie Cup an 810 Linhof Master TL to do their record work. That was to photograph, at 1:1, all of their production run products. That included not only plastic cups but also plastic dinner plates. To ensure that these round plates and the round cups remained round in the images they used a 480mm at 1:1. This required a Linhof double extension 810 bellows that was custom made to have a 57 opening in the front plus a custom Linhof auxiliary standard to accept the 57 bellows on both sides plus a Linhof 57 bellows. Then they needed the largest Linhof Studio Stand for the camera and a Linhof Heavy Duty Pro tripod under the lens that was a long way from the camera! First they tried the Apo Ronar 480 but it wasn't that good on these 3D objects so then they went to the 480mm Sironar-N MC which was far better. Even though it was well out of its optimization range. Probably because the Apo Ronar was corrected for f22 while the Sironar performed better at a range of stops and that fitted their requirements.

[Tin Can]

I shoot my 480 APO Ronar, w/o MC label or coatings mostly in studio 1 to 1.

Looks good to this guy.

I took my elements out and thought I spotted a shim, that shiny wide space with 2 opposing holes, but that's not a shim nor a contact area. No shim.

143339

[8x10 user]

two shims

143340

[8x10 user]

Didn't the Computar have two shims, a smaller one that corrected everything to spec and a larger one that changed the optimization to 1:1?

[europanorama]

apropos shim. When i was testing apo-gerogons 210 and 240 with double-sunshade front element came out. found a shim later-accidentally on ground....Dont want to tell for which camera-system otherwise i will get a complaint.....

[europanorama]

Just to say that I have a long Apo ronar CL mounted on a sinar copal shutter, without any modification on the lens itself (as far as I know) and it gives razor sharp images for landscape...
Emmanuel Biggler on the french forum "galerie photo" is fond of theese lenses.

143325


143326

Quick scan with a bad scan (epson 4870) of part of an 8x10 slide.
Taken from San Giorggio Maggiore, so at a distance of about, let's say 500 m, so I think we can talk about infinity...

Hope that it can help...

Thierry M.L.
with firefox zoomfox addon one can enlarge more but its not that sharp to check the orginal quality.

[europanorama]

Actually the factory states that the Apo Ronars are optimized for 1:1 but since they are symmetrical designs that they work out to infinity and would out perform most Tele designs. But the will not equal the N or S or W Sironars at those ratios.
Bob, did you mean the APO-sironars since i have seen your detailed precise report about the N and S in photo.net.
http://photo.net/large-format-photography-forum/00Pw5F

[plaubel]

they went to the 480mm Sironar-N MC which was far better. Even though it was well out of its optimization range.

Did they use it in retro/reverse position, or in normal position?
Or is the Sironar a symmetric lens ?
The long bellows is the reason for me to use short lenses like my 150 Componon S in Copal shutter.
Making round cups more round with a longer lens is a nice tip, thanks..
Ritchie

[Bob Salomon]

Did they use it in retro/reverse position, or in normal position?
Or is the Sironar a symmetric lens ?
The long bellows is the reason for me to use short lenses like my 150 Componon S in Copal shutter.
Making round cups more round with a longer lens is a nice tip, thanks..
Ritchie
Normal. The Sironar-N and later versions are not symmetrical. A short lens would create foreshortening and round objects would then become more of an oval.

[TML74]

with firefox zoomfox addon one can enlarge more but its not that sharp to check the orginal quality.
Believe me, the best thing to do is to see the slide with a lupe on a lightbox and then I can say that this slide is really sharp, the one I got with my schneider 210 SA-XL are not sharper...
Really I am very pleased with this 1070 apo ronar CL. just a bit heavy and quite long to use with such a long bellow on the 8x10 sinar...
Thierry M.L.

[europanorama]

There is an Apo-sironar 210/5.6 WS

[Bob Salomon]

There is an Apo-sironar 210/5.6 WS

No there never was.

[Armin Seeholzer]

There was an APO Sironar 210/5.6 W witch covered 8x10 its in my Rodenstock Brochure from 1992 of course in german written!

[Bob Salomon]

There was an APO Sironar 210/5.6 W witch covered 8x10 its in my Rodenstock Brochure from 1992 of course in german written!

Armin, the Apo Sironar-S 210 also covered 810. But just barely.

[Armin Seeholzer]

And about the Apo Ronar I was talking many years ago with mister Wenzel from Rodenstock hope I remember the name right, and he told me that they started to optimized the APO Ronars with had a shutter for 1:10 witch means almost for infinity!
And I know very well Bob you are not learning new things very well, its not the first time I tell this story and I'm so tired to tell it every 3-4 years again!!!!

[Bob Salomon]

And about the Apo Ronar I was talking many years ago with mister Wenzel from Rodenstock hope I remember the name right, and he told me that they started to optimized the APO Ronars with had a shutter for 1:10 witch means almost for infinity!
And I know very well Bob you are not learning new things very well, its not the first time I tell this story and I'm so tired to tell it every 3-4 years again!!!!

Then you should have told Dieter Wenzel to have corrected all their literature that should it corrected for 1:1. And any time I spoke or saw Dieter, or anyone else at Rodenstock, this was never mentioned.
However, since these lenses have been out of production for several years and since our company closed in Feb and the Rodenstock distribution is now with a new company, that I do not work for, I am no longer involved with Rodenstock in any way. So I will leave it to the new distributor to solve this mystery, if they wish.

[tgtaylor]

I have the 480 in a modern - all black copal shutter with the f stops all evenly spaced on the scale. It's fully open at the f/9 but continues to stop-down for ~ 25mm past f/90 on the scale - f/128, f/256?

Thomas