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...



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.