600mm APO-Ronar vs 600mm APO-Germinar...but wait, there is more

[light-zone]

my guess is, the CL refers to Coated / Linear. Coated glass and a linear apeture. But that's just a guess from a guy who has learned everything he knows about Apo-Ronars from this thread ;-)

[arne_croell]

The L in CL might refer to the linear scale. I don't think the coating is different, at least Rodenstocks brochure doesn't mention it. They do say, however, that the CL Ronars are better centered. They describe it in the process lens brochure I have. Instead of the usual mechanical mounting the lenses are first centered/oriented in the mount using autocollimation and are then permanently fixed in that position by injection of some plastic. According to Rodenstock this reduces stress-induced birefringence and reduces the variation of the MTF in production from 0.1 down to 0.05.

Of course this process also means that an Apo-Ronar CL cannot be taken apart.

[arne_croell]

WRT Davids comment: there certainly was a 600mm CL with four lenses around. My Roidenstock brochure from 1982 (printing date - I got it from Rodenstock around 1990) lists it both as plain Apo-Ronar and as CL version with 4 elements. I don't know if the 6-element version that Joerg mentioned was poduced before or after that time frame.

[david_bradley1]

What a coincidence. Just yesterday at dinner my wife commented that some of my images showed signs of stress-induced birefringence. We brainstormed and figured that some autocollimation might just do the trick. Small world. :-)

 

But seriously, does this mean that my new, big, beautiful, pristine, sexy 600mm/9 APO-Ronar-CL can't be mounted in a shutter? Say it isn't so!

[joerg_krusche]

Hi again,

 

as I said in an earlier message in this thread, there are four element and 6-element Apo Ronar's. The 9/600's are all four element. The 6-element is an F=11/600 lens (CL version only). The four element 9/600 Apo Ronarr CL weighs 1561 grams, while the 11/600 6-element weighs 1547 grams.

 

All process Apo Ronar's were single-coated, employing a few layers of Magnesiumfluoride I assume. Only a few of the 16/1000 mm Apo Ronar's (all 16/1000 are 6-element or if older version are 8-element) were also offered multi-coated (as guessed by the multi-colour reflections). These latter one's were about twice the price of the equivalent focal length 4-element versions, and these were not dirt cheap. The 6-element versions were offered for extra critical jobs.

 

As for infinity performance, Rodenstock says in one of their brochures that the long focal lengths Apo Ronar's are hard to beat by tele designs. I recently took a few shots in the 750 - 1200 range, Apo Ronar's and others vs Nikkor T-ED (a very good tele-design), and by just having a qualitative look at the negatives, the repro lenses are equivalent (resolution) and certainly give a much wider image circle in these long focal lengths.

 

BTW, this may not belong into this group, the Apo Ronar's are superb long lenses if you have a MF camera with focal plane shutter, bellows (as the Rollei SL 66) .. all you need to make is an adapter and a tube with internal baffles to maintain high contrast.

 

Best

 

Joerg

[bob_salomon]

Again, the 480 is the longest Apo Ronar that fits into a #3 shutter. So your 600

would not fit a #3. Now if you can find a good #5 you could have someone

make adapters so the 600 cells would fit it.

[arne_croell]

David: the CL should be adaptable to a shutter, I think. I was referring to taking individual cells apart for cleaning. However, I never had one in my hand, so take it with agrain of salt.

 

It should be possible to adapt longer focal lengths than 480mm in a no. 3 Copal with custom made adapters if the distance between the two cells is significantly bigger than the thickness of the shutter (I don't know if this is true for the Ronars). Of course your maximum opening would go down accordingly. Maybe Steve Grimes can comment on this if he is following this thread.

[arne_croell]

One additional comment on the infinity performance mentioned by Joerg: The late German photographer Reinhart Wolf (already mentioned today in the other thread on dual tripods) used the Apo-Ronars 360mm, 480mm, 600mm, and 1000mm for his 8x10 photos of New York skyscrapers (in the book "New York")and of Spanish castles ("Castillos"). That is quality assurance enough for me.

Joerg, sorry you missed me afew days ago. I'm looking forward to your information on the Germinar-W. Arne

[arne_croell]

David I hope your pictures are not too birefringent after all :-).

I enjoyed your comment; I just translated Rodenstocks text from German, but I think I owe an explanation here, although it may be somewhat off-topic.

 

Birefringence due to mechanical stress essentially means that the refractive index of a material (glass in this case) changes if you apply pressure or bend it etc. (actually it induces the separation of the refractive index into TWO different indices for differently polarized light - that is why its called "bi"refringence). A change of refractive index is obviously detrimental to the quality of the image.

 

Autocollimation: imagine a point light source exactly one focal length from your lens. This results in a parallel beam of light on the other side of the lens. If you place a mirror on that side, the beam is reflected back through the lens and forms an image point again. Only if the lens is absolutely perpendicular to the mirror AND if the lens elements are perfectly centered will that image point coincide with the point light source. Otherwise it is laterally displaced by some distance. Some of the tools to adjust enlarger stages use a similar principle, like the Versalab "Parallel" or the Zig-align.

[joerg_krusche]

Hi,

 

Arne just to pick up what you just referred to: there is a simple test for mechanical stress/distortion. You just take two linear crossed polarizers, one each on both sides of the lens in question. If there is stress, then you may see light shining through the lens.

Smooth heating and a bit of tapping sometimes may help then.

 

Best

 

Joerg

[kelly_flanigan1]

Over zealous tightening of a lens retaining ring warps the lens element at the micro level. The fringe pattern gets worse when overtightened; or if a burr is present; or if the retaining surface that contacts the lens is not perfectly 90 degrees to the axis of the threads of the retaining ring. In making custom lens mounts; we would test lens elements before and after mounting; a poor mount stresses the lens in a uneven way. Also the lens mount must not warp the lens element or mirror due to thermal stress. The optical centering of lenses in loose bores; and then gooping them in place has been done with custom optics for years. The other ways are either using the mounts bore to define the lenses edge; and use a compliant retaining ring. Or; use a loose bore; and have the retaining ring define the centering; because the ring will allow the spherical surface to move around and center on the ring. If the lens mounts threaded bores are not concentric; the retaining ring with loose bore method will have centering problems too.<BR><BR>My 1971 Pro catalog "process lens page" lists a 800mm F9 Apo Ronar-<b>S</b> with a footnote that the <b>S</b> is for a Apo-Ronar in Shutter<BR><BR>The 1971 Pro catalog "still camera lenses" list a 1000mm F9 Apo-Ronar in Compur Electric 5; a 600mm F9 in compur electic 5; and a 480mm F9 in compur electric 5...............What the heck is a compur electric 5??????<b>BOB</b> What does CL on a APO RONAR mean?

[bob_salomon]

"BOB What does CL on a APO RONAR mean?"

 

Linear aperture scale

[joerg_krusche]

Kelly,

 

the Apo Ronar 9/800 does NOT fit into any standard shutter up to #5.

 

The in '71 offered Apo Ronar 16/1000 in a Compur Electronic 5 FS was still the FAMOUS 8-element version. Dr. Naumann (for his biography see Kingslake's book) wrote an article on this superlens back in the early seventies if I remember.

 

Best

 

Joerg

[light-zone]

<b>Hey BOB,</b>

 

if <b>CL</b> means Linear Apeture Scale, then what does <b>L</b> stand for in the Apo-Ronar L?

[arne_croell]

Joerg, yes, that is the standard setup for birefringence testing in a "polariscope". As you mentioned its is important to use linear polarizers, or, if one uses circular polarizers, that the outside of the filters point towards the test object. A good example of the effect is to use a transparent plastic ruler (which is often already birefringent from the molding process) and bend it between crossed polarizers.

[bob_salomon]

"then what does L stand for in the Apo-Ronar L"

 

No idea it is not something sold in the photo market so we have no factory

information on it. Since these are graphic arts lenses you might try asking in a

graphic arts forum (if there is one).

 

Rodenstock makes, and made, all types of optics for applications other then

photographic - like Xray, Laser, machine vision, CD readers, etc. We only

have references for those designed for photogrpahy.

[david_bradley1]

To further clarify about the scales on the CL version of the Ronar, here are some pictures of the scales on mine. In addition to the usual scale that represents the iris opening in terms of f-stops there is a second scale on the other side of the lens that reprents the iris opening in millimeters. I assume the term "linear aperature scale" mentioned in previous responses refers to the millimeter scale, but I could be mistaken.

 

By the way, the wide red line in the pictures (under "1:9 f=600mm/24in.") is an opening into which filters can be inserted. I'm told this is common is barrel-mounted process lenses.<div></div>

[bob_salomon]

Linear scale means the distance between apertures as marked on the

aperture scale are equally spaced from each other.

 

The size markings in mm were used by operators of graphic arts cameras.

[david_bradley1]

<BLOCKQUOTE>

<I>the Apo Ronar 9/800 does NOT fit into any standard shutter up to #5.</I>

</BLOCKQUOTE>

This collection of

<A HREF="http://www.skgrimes.com/fits/index.htm">pictures of barrel lenses mounted into shutters</A> on S. K. Grime's site shows a 750mm/f9 6-element APO-Germinar mounted in an Ilex #5 shutter. It seems like the 800mm/f9 Ronar (which has basically the same optical formula, yes?) would also fit in a #5 shutter. To retain f9 the max shutter opening would have to be about 5.5mm larger, so perhaps there might be a slight loss of maximum aperature. Just conjecturing here.

[kelly_flanigan1]

BOB; thanks for the answers. <BR><BR>Joerg; the "still camera lenses" reference table on page 126 in "the 1971 Reference & Buying Guide for Industrial & Graphics Arts Equipment" shows the apo-ronar's of 1000mm, 600mm, & 480mm in Compur Electric 5 . Either the table is in error; or maybe a specialized larger shutter was made for the graphics arts market; and mislabeled an "electric 5" . The graphics arts market used many off the shelf "photo and enlarging" lenses; and added shutters. These stock or custom shutters were not marketed thru normal photo dealers; and were sold to graphic arts dealers. Many times I have read threads on this board about a shutter not existing for a lens; when I have seen the lens in usage with a shutter. We used a 210mm F5.6 Schneider Componon in Sychro Compur for one decade; I got an email once from a fellow who said it never existed; and quoted web site which said so. Such is the murky world of optics; many tables have errors...

[light-zone]

<i>No idea it is not something sold in the photo market so we have no factory information on it. Since these are graphic arts lenses you might try asking in a graphic arts forum (if there is one). </i>

<p>

I was under the impression that the CL version is also a "Graphic Arts" lens, correct?

[kelly_flanigan1]

Our longest Ronar is a 890mm and is only a F14 lens. I believe some of the tables out there are in error; one showed a 890mm F9; where ours is a F14. These tabular errors get copied yet into another table or website; and add to the confusion.

[bob_salomon]

"the CL version is also a "Graphic Arts" lens, correct"

 

Correct. All Apo Ronar lenses are. But the CL happens to be listed in a

brochure for the Apo Ronar process lenses as were the Apo Rodagons

longer then 180mm and the Apo Geragon series and some enlarging lenses..

[kelly_flanigan1]

Graphic Arts is a dead market; I believe Bob will agree with me on that concept. With small F32 apertures being used; the actual exposure is usually done with a timer on the arc lamps illuminating the copy platten. With Typical Kodalith asa 6; exposures are many seconds. With the rare greyscale job; the timer many times needs to be say 0.2 seconds with asa 100 film; which is difficult to do with a darkroom timer. Either a giant ND filter is used; or a leaf shutter; which is rare in giant process lenses. May of us used a black hat as a shutter; with another person in the other room contolling the arc lamps. The pulsed Xenon lamps fire with the 60 cycle line frequency; thus a super short exposure adds alot of weird color problems sometimes. <BR><BR>The apo ronars of ours are stopped down to F22 or f32 to mask field curvature. These are "flat field" lenses; with little distortion; but the corners will be not sharp; and the center sharp when used at F9. The warning sticker on our process camera mentions this; and the rodenstock data we have on each lens serial number. Most short apo ronars work best at F22; and real long ones F32.<BR><BR>

[joerg_krusche]

Kelly,

 

sorry my fault, by FIT INTO A SHUTTER, I understood that you can SCREW the cells into the shutter without any further machining etc. i.e. just manually within a few seconds. None of the repro versions of the Apo Ronar's fit this way into standard shutters, BUT with some proper machining you can make them fit, through the services of S.K. Grimes or equivalent people. This with some more or less efforts can be done with most of the Apo Ronars, that includes the 9/800. You may have to check whether the spacing of the cells is big enough for the intended shutter.

 

The Apo Germinar 9/750 is BASICALLY the same design as the 9/800's Apo Ronars, except that the Apo Germinar (an outstanding lens) is a 6-element ALL-AIR SPACED design while the 9/800 Apo Ronar, also a 6-element design (whichever version, they differ only by whether elements 1+2 or 2+3 on each side are cemented) has cemented elements.

 

My previous note (somewhere above) agrees that there was a 16/1000 Apo Ronar in a COMPUR ELECTRONIC 5 FS shutter. You could have all the other Apo Ronars you mention as well in this shutter (480/600/1000). This shutter is well-built, mechanically strong, and does have large threads on both sides (85mm), therefore is a good candidate to mount large cells on both sides or to front mount.

Times are from 1/60 to 32 seconds.

 

Best

 

Joerg