Spacers of Sinaron W 90/4.5 DB mount, for the same lens in Copal#1 ?

[Thalmees]

Spacers of Sinaron W 90/4.5 DB mount, for the same lens in Copal#1 ?
Hello everyone,
Used Sinaron W 90/4.5 in DB mount for the past 12 years.
It has tow(2) spacers for the front element, between the front cell and the DB mount.
Sinaron W 90/4.5 is the equivalent of Rodenstock Grandagon-N 90/4.5, BTW.
My query:
Does the lenses in Copal comes with front cell spacers? as DB mount lenses do?
Is the same spacers necessary for the same lens came in(or converted to) Copal 1 shutter ?
I do not know if the lenses in Copal1 comes from the factory with spacers or not?
If you have the lens in Copal shutter(Sinaron W or Grandagon-N), please find if there is any spacers?
That may provide the ultimate unswer, I think.
Spacers fit exactly on the shutter, are the same size of external circumference of the lip(mount) of the Copal#1 shutter mount.
Appreciate any input.
Regards.

[Pere Casals]

I guess this is about the shims adjusting the distance between cells in Rodenstock lenses.

Those shims are a factory adjustment to provide the particular optimal distance between cells in each unit. If you vary that distance with different shims then you can optimize the lens to work better for near or distant subjects, or to work better in the center or in the corner. For each particular lens, and after optical measurements, Rodenstock could add a shim of a particular thickness, more than one or none, to make each unit perform as better as possible.

If the lens had those shims when DB mounted then you have to move those shims to the copal it is replacing the DB. The shims are a component of the lens, not of the shutter. ...so when you replace the shutter (or the mount) the shims have go with the glass.

If you buy a used lens it can happen that the shims are lost, or because ignorance somebody placed there shims that are not the right ones when a shutter or DB was replaced, this would make the lens to not work with the same performance than when delivered by the manufacturer.

[Bob Salomon]

I guess this is about the shims adjusting the distance between cells in Rodenstock lenses.

Those shims are a factory adjustment to provide the particular optimal distance between cells in each unit. If you vary that distance with different shims then you can optimize the lens to work better for near or distant subjects, or to work better in the center or in the corner. For each particular lens, and after optical measurements, Rodenstock could add a shim of a particular thickness, more than one or none, to make each unit perform as better as possible.

If the lens had those shims when DB mounted then you have to move those shims to the copal it is replacing the DB. The shims are a component of the lens, not of the shutter. ...so when you replace the shutter (or the mount) the shims have go with the glass.

If you buy a used lens it can happen that the shims are lost, or because ignorance somebody placed there shims that are not the right ones when a shutter or DB was replaced, this would make the lens to not work with the same performance than when delivered by the manufacturer.

Sorry, shutters have mechanical tolerances as do DB systems. The shims are added by the factory after optical bench measurements after being mounted to the shutter it will be used on.

[Pere Casals]

Sorry, shutters have mechanical tolerances as do DB systems. The shims are added by the factory after optical bench measurements after being mounted to the shutter it will be used on.

Bob, of course it is not a bad industrial practice deciding the shimming depending on the particular shutter's actual thickness, but (modern) shutter thickness tolerance are specified at +/-0.025mm, while it is very difficult to notice a performance loss with a change under 0.05mm, anyway some may see a difference in lab conditions with a 0.02mm change.

...but actual (measured) variability of shutters' thickness are much smaller than specs, so IMHO that variability should have no impact in the performance. And for sure that moving the shims with the lens to a new shutter is the best bet we can do, doesn't it? ...because if a shimmig adds 0.30 mm for example... this would be noticed !!

Well, ideally we should measure the original and the replacement shutters (with a 0.01 precission tool) and modifiying the shimming if a difference is found, true. If not doing that then the next best choice is reusing the shims...

[Bob Salomon]

Bob, of course it is not a bad industrial practice deciding the shimming depending on the particular shutter's actual thickness, but (modern) shutter thickness tolerance are specified at +/-0.025mm, while it is very difficult to notice a performance loss with a change under 0.05mm, anyway some may see a difference in lab conditions with a 0.02mm change.

...but actual (measured) variability of shutters' thickness are much smaller than specs, so IMHO that variability should have no impact in the performance. And for sure that moving the shims with the lens to a new shutter is the best bet we can do, doesn't it? ...because if a shimmig adds 0.30 mm for example... this would be noticed !!

Well, ideally we should measure the original and the replacement shutters (with a 0.01 precission tool) and modifiying the shimming if a difference is found, true. If not doing that then the next best choice is reusing the shims...

Having spent 29 years as Product Manager for Rodenstock in the US I have seen everything from no shims in a 90mm 4.5 to one shim to multiple shims. It depends on the specific lens/shutter combination. Lenses have tolerances as do shutters!

I’m sure that you have also seen that many lenses as well!

[Pere Casals]

I’m sure that you have also seen that many lenses as well!

Yes... but for example fujinons as less prone to include shims, even for the wides.

I was thinking that perhaps some designs were relying in shimming for optimization. My guess was that the designer could make the lens to have little effects when changing the spacing, or the counter... the design could seek an effect for example to allow to optimize one factor or a set of correlated factors...

Just guessing....

[Thalmees]

Having spent 29 years as Product Manager for Rodenstock in the US I have seen everything from no shims in a 90mm 4.5 to one shim to multiple shims. It depends on the specific lens/shutter combination. Lenses have tolerances as do shutters!
I’m sure that you have also seen that many lenses as well!

Thanks Bob for your input.
That's only true if you are talking about a new batch of lenses just departed the factory.
Assuming that 50% of all new lenses made during a period of past time, distributed with shims, regardless of number of shims. And 50% did not need.
By the current time, in used market, I do not think we will find 5-10% of the same batch of lenses having shims, for obvious reasons of handling, maintenance and just being easily missed plus scarce availability and knowledge about them.
But hopefully, testing for the effect of shims on a particular lens that came without one, is not extremely difficult, of course not of lab precision but with reasonable accuracy.
At the same time, if a lens needed a shim of certain thickness, it's near impossible to find it today.
Thanks so much again Bob.

[Bob Salomon]

Thanks Bob for your input.
That's only true if you are talking about a new batch of lenses just departed the factory.
Assuming that 50% of all new lenses made during a period of past time, distributed with shims, regardless of number of shims. And 50% did not need.
By the current time, in used market, I do not think we will find 5-10% of the same batch of lenses having shims, for obvious reasons of handling, maintenance and just being easily missed plus scarce availability and knowledge about them.
But hopefully, testing for the effect of shims on a particular lens that came without one, is not extremely difficult, of course not of lab precision but with reasonable accuracy.
At the same time, if a lens needed a shim of certain thickness, it's near impossible to find it today.
Thanks so much again Bob.

Shims can be ordered from the factory via the service center or the Rodenstock distributor.

[Thalmees]

Shims can be ordered from the factory via the service center or the Rodenstock distributor.

Thanks so much Bob.
Thats also true only, if you know the shim exact thickness, or type if the shims used to be known by type.
I read about shims in order of 0.5mm, but when I measure the shims in a friend of mine lenses, it's from roughly 0.05 to 0.15mm(all lenses are short focal length lenses). I think the thickness is not the same with older long focal length lenses.
The actual scenario in the current used market is, whether there is a missed shims or not? Then what's the appropriate shim thickness?
Please let me know if Rodenstock still accept used lenses for calibration and testing, and how much that service may charge?
Best Regards.

[Bob Salomon]

Thanks so much Bob.
Thats also true only, if you know the shim exact thickness, or type if the shims used to be known by type.
I read about shims in order of 0.5mm, but when I measure the shims in a friend of mine lenses, it's from roughly 0.05 to 0.15mm(all lenses are short focal length lenses). I think the thickness is not the same with older long focal length lenses.
The actual scenario in the current used market is, whether there is a missed shims or not? Then what's the appropriate shim thickness?
Please let me know if Rodenstock still accept used lenses for calibration and testing, and how much that service may charge?
Best Regards.

Of course they will recalibrate lenses but you would have to check with them or the distributor in your country as to the cost. It is strongly suggested that your distributor handle shipping as an error in paper work can lead to very expensive VAT charges.