help with lens reconstruction! Symmar S 150mm

[Leon]

Camera Lens/ Optics Aficionados - HELP!!!!

I have a Schneider Symmar S 150mm that had a bit of haze forming inside, so I have taken it apart to clean it. I rather stupidly did not take note of which way around the elements went


My question is, which way does the middle element face? Does it echo the curve of the front element (eg curve facing away from the film plane) or does it echo the rear element (eg curve facing towards the film plane)? It fits nicely both ways.

I cant find any diagrams of the lens online

thanks in advance

 

[AgX]

As being symmetrical, there is no middle element.

Maybe you refer to the middle elements in the two main (Gaus) sections?
The middle elements of both sectios have their flat (more flat) side facing outwards (refering to the completed lens).
But aren't they cemented??


Maybe you are refering to the two inner elements (elements of the Gaus sections facing the shutter)?

Both are facing their hollow side to the shutter.




The name Symmar reflects its nearly symmetrical construction. Thus one can take the other Gaus section as sample.
(I have to admit though, opening a fine section without better cause than to look at its construction is not the best idea. Then better ask here.)

 

[Xmas]

The bulges should bulge away from the iris.

It is undesirable to swap the inner pair even if they will physically fit...

 

[chrisaisenbrey]

Hello Leon,

Perhaps the small figure in the Schneider leaflet helps.
The leaflet is from the Schneider homepage, before they updated their homepage.

Chris

 

[Leon]

thanks all. Problem fixed now

 

[Leon]

and Chrisaisenbrey - thank you! I couldn't find that leaflet anywhere, I know I had seen it in the past.