Identifying correct rear element and shutter for lens

[uncommonfaces]

I'm unable to find any information on this.

It seems possible that rear elements from different focal lengths can be added to lenses/shutters by sellers either "sneakily" or unwittingly. Likewise, Copal shutters with insufficient max f stop for the given focal length.

What are the implications of interchanging rear elements on the Fujinon lenses for example and how do you know if you have the right one? Lots of spec information online for these lenses, but can't see anything about this.

I would like to ask the same of Copal shutters (for which the Fuji at least have a specific design, but are they identifiably different for each focal length?)

Sorry if this is really obvious.

[uncommonfaces]

To clarify on shutter, 5.6-64 Copal 0 from a 90mm put on a 125mm (which is also 5.6-64)

[Pere Casals]

It seems possible that rear elements from different focal lengths can be added to lenses/shutters by sellers either "sneakily" or unwittingly. Likewise, Copal shutters with insufficient max f stop for the given focal length.


The same shutters have different aperture scales, for each particular lens the scale has to be "printed" specifically, because the same "hole" in the iris is a different aperture depending on the particular lens model, not the focal, but the particular design/focal.

If you replace the shutter you may need to "glue" a different scale on the shutter. Many used lenses (in the auction site, vg) show a shutter that is looks not the original one, so if the aperture scale is the right one this has to be checked.

If a diafragm in a copal opens to it's maximum then there is no limitation beyond what the shutter model allows, IMHO...

Aperture scales can or could be purchased, or you can DIY calibrate and print one.




What are the implications of interchanging rear elements on the Fujinon lenses for example and how do you know if you have the right one?


If the real cell is not the right one then that lens may still project an image but of low quality.

A photographic lens, and in particular a LF lens with a large circle is a little technical miracle. The rear cell of a LF (two cell) lens compensates aberrations from the front cell in the right direction in precise oposite ammount , only in "convertible" lenses each cell is (more or less) individually corrected to be used alone, like in the old Symmar convertible models.

So if a rear lens is not the right one then the image it won't be sharp, this is something very difficult to find from a reputed seller.

Also manufacturers paired particular front and rear cells in the manufactured pool to have pairs that were balancing well the corrections, as we have a dispersion in the optical patrameters, so in many cases replacing a broken cell by another one of the same model is not an ideal situation.

Some manufacturers (mainly Rodenstock) sometimes added an special shim in the front cell to adjust optimal inter-cell distance, if the shim was there and it was lost then the lens also won't perfrom optimally.

There is a particular lens, the Nikon T, that a front cell may take three different real cells to have 3 focals.

When you buy a lens you have to know what to expect from that kind of glass, buy from reputed sellers accepting a return of the product, and if the lens is not good for you then return it.

[Bob Salomon]

To clarify on shutter, 5.6-64 Copal 0 from a 90mm put on a 125mm (which is also 5.6-64)

There are two small screws holding each of the aperture scales on a given shutter. Change the lens in the shutter to one with a different maximum or minimum aperture and you get the proper scales for the new lens. Scales are available from lens manufacturers or repair providers.

[Greg]

What are the implications of interchanging rear elements on the Fujinon lenses for example and how do you know if you have the right one? Lots of spec information online for these lenses, but can't see anything about this.

Suggest you get the page sized brochure "FUJINON PROFESSIONAL LENSES". In it are cross sections of Fujinon lenses with many dimensions listed in mms. Or you can view it online at
http://www.thalmann.com/largeformat/apr-1981.htm
Unfortunately many times the rear element groups have no writing on them. I have bought at the auction site many Fujinon lenses over the years. Twice the wrong rear element group (or maybe front, can't remember) was on the lens. Tested one of the lenses and the image projected was terrible. In both cases was able to return the lens, but as to if the seller "sneakily" or "unwittingly" knew this, I will never know the answer to that question.

[Bob Salomon]

Suggest you get the page sized brochure "FUJINON PROFESSIONAL LENSES". In it are cross sections of Fujinon lenses with many dimensions listed in mms. Or you can view it online at
http://www.thalmann.com/largeformat/apr-1981.htm
Unfortunately many times the rear element groups have no writing on them. I have bought at the auction site many Fujinon lenses over the years. Twice the wrong rear element group (or maybe front, can't remember) was on the lens. Tested one of the lenses and the image projected was terrible. In both cases was able to return the lens, but as to if the seller "sneakily" or "unwittingly" knew this, I will never know the answer to that question.

When we took over the distribution of Rodenstock lenses for the USA from Berkey Marketing we also had to take over their inventory. With the understanding, contractually, that any lenses not in factory new condition would be returned.
I had to personally open and inspect each lens. Among the lenses sent to us I found some with switched elements, some with no rear group and a 480 Sironar N with a huge fingerprint on the front element. All were returned to Berkey!

[uncommonfaces]

If you replace the shutter you may need to "glue" a different scale on the shutter. Many used lenses (in the auction site, vg) show a shutter that is looks not the original one, so if the aperture scale is the right one this has to be checked.

If a diafragm in a copal opens to it's maximum then there is no limitation beyond what the shutter model allows, IMHO...

So would all Fujinon Copal 0 shutters have the same diaphragm max and min opening? So even 5.6-32 shutter on 105mm has the same diaphragm as 5.6-64 on 125, just a different scale stuck on?

[Louis Pacilla]

So even 5.6-32 shutter on 105mm has the same diaphragm as 5.6-64 on 125, just a different scale stuck on?

So "just a different (((matching))) scale stuck on. YES!

[uncommonfaces]

Suggest you get the page sized brochure "FUJINON PROFESSIONAL LENSES". In it are cross sections of Fujinon lenses with many dimensions listed in mms. Or you can view it online at
http://www.thalmann.com/largeformat/apr-1981.htm
Unfortunately many times the rear element groups have no writing on them. I have bought at the auction site many Fujinon lenses over the years. Twice the wrong rear element group (or maybe front, can't remember) was on the lens. Tested one of the lenses and the image projected was terrible. In both cases was able to return the lens, but as to if the seller "sneakily" or "unwittingly" knew this, I will never know the answer to that question.

That is a very good resource, but unfortunately only covers one of the six Fujinon 125mm and not the one I'm looking at (why did they make so bloody many?).

This is the second 125mm I've looked at, not tested yet beyond functionality. The first one I tested seemed to be producing a poor image which baffled me. I'm wondering now if this may have been part of that.

[Pere Casals]

So would all Fujinon Copal 0 shutters have the same diaphragm max and min opening? So even 5.6-32 shutter on 105mm has the same diaphragm as 5.6-64 on 125, just a different scale stuck on?

My shutters (this one is a compur I now have with me) have two screews in the back limiting the min/max travel of the aperture lever, limiting the max aperture there is an screew you can move to another position to set the maximum aperture. I'll post some images...

186779

I don't know if all copal have exactly this, but a similar way should be there.

In the other side the lever (min aperture) also has an screew to limit the travel, but it has no other holes to move the screew to another position.

So beyond the scale you may have a mechanical limiter of the lever's travel that should be easy to remove. These screews (in my case) are in the outside of the shutter, only the rear cell has to be removed to have access, no need to disassemble anything in the shutter, other shutters may require to remove a cover (for example) to modify the mechanical top limiting the lever travel.

It's my understanding that any copal should be able to open to the max possible throat for the shutter size, but each model may have different (adjustable) mechanical tops for max/min. Those mechanical tops are for the user's convenience.

[uncommonfaces]

So "just a different (((matching))) scale stuck on. YES!

So just to clarify, the 90mm with the same aperture range as the 125mm. On both shutters, the diaphragm diameter will be the same at same apertures or the scales will be positioned in different places? (This is also a veiled optical question I appreciate, but LF has taught me I know nothing)

[Louis Pacilla]

So just to clarify, the 90mm with the same aperture range as the 125mm. On both shutters, the diaphragm diameter will be the same at same apertures or the scales will be positioned in different places?

"the scales will be positioned in different places" YES!

So if the original scale was for a 90mm focal length & set at 5.6 it will be f 5.6. However,,,, if the same 90mm fl scale is used for a focal length of 125mm and set at 5.6 it will NOT be f 5.6 for that focal length. You need the scale for the 125mm FL for it to match.

[uncommonfaces]

"the scales will be positioned in different places" YES!

Thank you, knowledge acquired!

[Pere Casals]

So if the original scale was for a 90mm focal length & set at 5.6 it will be f 5.6.

Not only because of the focal, a different design with same focal may require a different scale.

[Dan Fromm]

OP, a lens' f/number is the diameter of its entrance pupil divided by its focal length. The entrance pupil is the aperture's image as seen through the lens' front cell.

F/numbers engraved on shutters or on metal tapes held to shutters by screws are lens specific. There is no such thing as an f/5.6 shutter. There are shutters with aperture scales whose lowest f/number is f/5.6. A shutter's aperture control (lever, usually) controls the diameter of the diaphragm's opening.

About mixing and matching front and rear cells. Some, not all, lenses are double anastigmats. Each cell of a double anastigmat is, in theory, fully corrected for all aberrations and can be used as a taking lens. Practice sometimes falls a little short of theory.

Double anastigmats with identical front and rear cells are called symmetric double anastigmats. Goerz' Dagor, for example. Most of them can be used as convertible lenses, i.e., with one cell, usually the front, removed. This gives two focal lengths.

Double anastigmats with unequal front and rear cells are called asymmetric double anastigmats. They're intended to give three focal lengths, rear cell alone, front cell alone, and the two combined, so are also called triple convertible. The Cooke Ser. XVa Triple Convertible, for example.

Some asymmetric double anastigmats were sold with more than two cells, to give still more focal lengths. In English these beasts are called casket sets. In French, Trousse, as in Berthiot's Trousses d'Eurygraphes. In German, Satz, as in Meyer's Plasmatsatz. A few people here have suggested using cells from Schneider's Dagor type G-Clarons to assemble casket sets.

The Cooke Ser. XVa excepted, there are no relatively modern convertible lenses. The last symmetric double anastigmats were probably Boyer's Beryl/Emeraude, Saphir BX/Zircon and f/2.8 Saphir. All were sold as convertible. As far as I know, Fuji and Nikon never made convertible lenses. The last convertibles from Rodenstock and Schneider were, respectively jes' plain Sironars and jes' plain Symmars. Schneider's pre-WW II Angulons were sold as convertibles, post-war Angulons were not.

[uncommonfaces]

Thanks all. So after thinking more simply about this, the scale on shutter matches the lens aperture range (known), if I open the diaphragm to edges of rear of front element, the pin is at 5.6, so seems it probably is the right scale and shutter. Maybe measuring f64 opening for sanity will confirm for sure?

Re. the rear cell question, shooting negs and judging quality might get a bit subjective, so I'm still wondering if there is a surefire way to confirm if this cell is correct? It does have a serial and Fujinon print, which is helpful, but the front cell doesn't have a serial.

[Dan Fromm]

About serial numbers. Some makers engrave serial numbers on both cells. Others don't. Older 125/5.6 Fujinons have the s/n engraved on the trim ring and nothing on the rear cell. Newer ones have the name, focal length but not the s/n on the trim ring and the s/n on the rear cell. Mine is like that. Go figure.

About checking. There have been discussions here about how to measure a lens' focal length. Measure your lens' focal length. If your estimate is within 5% of the number engraved on the lens, all is well. If it is far off, all is not well.

About measuring focal length. This site has resources. A link to the one that points to the discussions I just mentioned is in the first post of this https://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses discussion. Click on it, download the pdf, ...

[uncommonfaces]

About serial numbers. Some makers engrave serial numbers on both cells. Others don't. Older 125/5.6 Fujinons have the s/n engraved on the trim ring and nothing on the rear cell. Newer ones have the name, focal length but not the s/n on the trim ring and the s/n on the rear cell. Mine is like that. Go figure.

About checking. There have been discussions here about how to measure a lens' focal length. Measure your lens' focal length. If your estimate is within 5% of the number engraved on the lens, all is well. If it is far off, all is not well.

About measuring focal length. This site has resources. A link to the one that points to the discussions I just mentioned is in the first post of this https://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses discussion. Click on it, download the pdf, ...

Thanks so much Dan. Re. allowing 5%, I'm measuring focal closer to 120 with my eyes and there is regrettably a 120 Fujinon. However, since both elements look multicoated and the 120 isn't, it appears all is well... or at least close enough for rock and roll.

[Dan Fromm]

The 120 Fujinon is a gross fat wide angle lens, the 125s are. except for the 125/8 SWD, relatively dainty little things. Which do you have?

Oh, and by the way, the list I directed you to has a list to an excellent source of info on Fuji lenses.

This discussion would have been concluded much more quickly if you have been more forthcoming. It is very helpful, when asking a question about a lens, to spell out what it is. Maker, focal length, maximum aperture, model as engraved, usually on the trim ring, ...

[uncommonfaces]

Sorry! For the record, 125 f5.6 W, 46mm filter thread (engraved on lens barrel).

[Pfsor]

"the scales will be positioned in different places" YES!


NO! The new scale, different from the old one, will be positioned in the same place on the shutter as the old one. After all, where else would you like to position it? It's good to know to express yourself technically correctly.

[uncommonfaces]

NO! The new scale, different from the old one, will be positioned in the same place on the shutter as the old one. After all, where else would you like to position it? It's good to know to express yourself technically correctly.

I took that to mean the "plate" will be screwed in same location, but the actual figures spaced/positioned differently?

[Pfsor]

You took it correctly.

[Dan Fromm]

Positioned differently, probably with the same spacing between stops. Linearity of spacing depends on the shutter.

I have a 125/5.6 Fujinon NW (in Copal #0; lens' identification engraved on the side of the front cell's barrel; 52 mm lens threads; serial number engraved on the side of the rear cell's barrel) in front of me. Original issue shutter, as far as I know. The aperture scale is linear, i.e., the linear and angular distances between tick marks for the stops are constant.

I also have a 60/5.6 Konica Hexanon, ex-Koni Omegaflex, in Copal #0 with aperture scaled by SKGrimes in front of me. The aperture scale is also linear.

The two shutters' scales place f/5.6 at different distances from the "wide open" position. The 125's is, as expected, closer to wide open than the 60's.

I believe, could be mistaken, that all Copal #0s have linear aperture scales. I don't have any late Compurs, do have older ones whose aperture scales are quite non-linear, small stops are closer than large ones. Copal #0 Press shutters seem to have large stops slightly closer than small ones. This last is a surprise.

[scm]

Yes, the plates fasten in the same location but the scales can be very different. Below are a couple of aperture scales, one for a 90mm/8, the other for a 150mm/5.6. As expected, there is almost a full stop difference between the two, ignoring the fact that one starts at f/8 and the other at f/5.6.

https://stevemidgleyphotography.com/Aperture_Scales.jpg

[Pfsor]

One picture speaks more than 2 lines of words. :)

[Jac@stafford.net]

If you are lucky, the rear lens will have a penciled or engraved serial number matching the front cluster.

[uncommonfaces]

Well I'm satisfied with this, lots of thorough info from all. Thanks again and apologies if convoluted.

Meanwhile, I continue to wait for the Intrepid...

[Pfsor]

I believe, could be mistaken, that all Copal #0s have linear aperture scales. I don't have any late Compurs, do have older ones whose aperture scales are quite non-linear, small stops are closer than large ones. Copal #0 Press shutters seem to have large stops slightly closer than small ones. This last is a surprise.

The actual aperture leaves in modern shutters are cut into such shapes that the aperture scales can be linear. It makes the aperture choice more logical to use, especially if you estimate 1/3 positions in between the common values. But there can be an optical illusion in play if you look at the printed values. Look at the example picture (thanks, scm!) above - the distance between 8 and 11 seems bigger than that between 32 and 45. Yet they are exactly the same.
Personally I have not seen an old shutter where the scales would not be linear. But of course, I have not seen them all.

[Dan Fromm]

If you are lucky, the rear lens will have a penciled or engraved serial number matching the front cluster.

Jac, in his very useful compilation of information on Fuji LF lenses (http://www.subclub.org/fujinon/index.htm) Joe McGloin differentiates between vintages of Fuji lenses of the basis of where identifying information is engraved. "Marked inside filter ring" (on the trim ring, in the common language) and "marked on the lens barrel" (front cell) identify, respectively, older and newer lenses. Joe wasn't much interested in where the s/n was placed. In the old type, it went on the trim ring with other identifying information. In the new type, it went on the rear cell. In neither type is it in both locations.