Magnification of lens groups in total optical system

  • 17 February 2021
  • 8 replies
  • 1539 views

I want to know about magnifications of each lens groups in entire optical system.


Especially, I wonder whether there are optimization operands about magnifications of each lens groups (defined surface to surface like operands EFLX, EFLY), or how to calculate the each magnifications of lens groups in entire optical system.


 


 


Sincerely


8 replies

Userlevel 7
Badge +2

Hi Min Soo,


I guess the answer depeds a little bit on your definition of the magnification.


Personnally, for an imaging system, I like to use the Merit Function operand REAY with an off-axis chief ray. I record its value in the object, and image plane, and then take the ratio to obtain the magnification. However, I see that you don't exactly have intermediate image planes in your design.


Would anything like that for you? How do you define the magnification? Actually, are you talking about angular magnifiaction? In this case, perhaps you could use the real ray angle of incidence operand (RAID).


Take care,


David

Userlevel 7
Badge +3

Hi Min Soo,


If you want to isolate individual parts of your system to examine them or optimize them separately, use the 'Make Conjugate'  in Setup...Configurations.


- Mark

Thank you for answer!! 


exactly i want transverse magnification! (like paraixial magnification in system data)!! 


sincerely! 


 

Userlevel 7
Badge +2

Hi Min Soo,


Right, can you share an example with us? Some file with dummy lenses, and the kind of numbers you want to get? It might be easier to explain.


Take care,


David

Dear David, 


Thank you for answer! Sure, I can send you a example file! Where should I send the example file?


Sincerely! 

Userlevel 7
Badge +2

Dear Min Soo,


The best is to upload an archive file (*.ZAR) to this forum using the Attach a file option at the bottom of the page.


Let me know if that's not clear.


Take care,


David

Dear David, 


There are 4 lens group in example file! 


A lens group (surf1~surf5), B lens group (surf7~surf12), C lens group (surf15~surf20), D lens group (surf22~surf27).


The focal length of each lens group is fixed. (The focus length value should not change.)


When i optimize distance of lens group, the transverse magnification of each lens group was changed.


so I want to fix transverse magnification of each lens group! (B,C,D lens group) 


Let me know if there is a problem with the file.! 


Sincerely :) 

Userlevel 6
Badge +2

Hi Min Soo


Thank you for sharing your file. I'll take the B lens group (surfaces 7-12) as an example. 


If you use Make Conjugate'  in Setup...Configurations. Note that you have to select a surface for the STOP, so you may need to check where the STOP is!



It will create a 2nd configuration:



In that configuration, as you can see the image is not defined properly. So the image needs to be set at the right location before evaluating the magnification. As David said, operands like REAY will give you the Y coordinate of a ray and then you can make a ratio.


Is this kind of solution working for you?


Sandrine

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