Question on Leitz objectives

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geo_man
Posts: 119
Joined: Mon Jan 21, 2019 4:54 pm

Question on Leitz objectives

#1 Post by geo_man » Sat Oct 19, 2019 11:44 am

Hi all. I purchased this 2.5x lens to add to my Leitz Dialuz POL to provide a wider field of view for scanning my slides. My current 4 Leitz Wetzlar Objectives are: 3.5/0.10 P 170/- --- 10/0.25 P 170/- --- 25/0.50 170/0.17 --- 50/0.85 P 170/0.17

Unfortunately the new 2.5x is very non parafocal with a much longer working distance. How do I determine which (if any) 2.5x objective would be approximately parafocal with my other objectives? Thanks in advance for any advice.
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luxikon
Posts: 22
Joined: Mon Mar 21, 2016 4:14 pm
Location: Northern Germany

Re: Question on Leitz objectives

#2 Post by luxikon » Mon Oct 21, 2019 8:10 am

Hi,

if you google for:
LEITZ Image-forming and Illuminating Systems_engl.pdf
you'll find a brochure with all the information you need
esp. adjustment length of all Leitz objectives.

In case you are German speaking search for:
LEITZ Abbildende und beleuchtende Optik_1973.pdf

Klaus

geo_man
Posts: 119
Joined: Mon Jan 21, 2019 4:54 pm

Re: Question on Leitz objectives

#3 Post by geo_man » Mon Oct 21, 2019 9:43 am

Thank you, luxikon. That is quite a document! I'll give it a look.

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jimur
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Re: Question on Leitz objectives

#4 Post by jimur » Mon Oct 21, 2019 10:21 am

Would a plezy not decrease the working distance for the 2.5x?
"You're never too old to have a happy childhood"
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Canon 450D

apochronaut
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Joined: Fri May 15, 2015 12:15 am

Re: Question on Leitz objectives

#5 Post by apochronaut » Mon Oct 21, 2019 12:40 pm

I am not sure about objectives in the Leitz 170mm D.I.N. system but it is not uncommon for very low power objectives to have a very long working distance and be not parfocal with the higher power objectives.

In certain instances, manufacturers offered two options; a standard l.w.d. option and a parfocal option, where the objective was in fact an undercorrected 5X with an extension that carried a reducing, overcorrecting lens at it's tip. The extension , brought the overall magnification down, the planarity and peripheral corrections up and the length of the objective to equal that of the rest of those that it was designed to be used with, for perfect parfocality albeit a limited w.d. The N.A. of the two versions was the same in the examples I am familiar with.

geo_man
Posts: 119
Joined: Mon Jan 21, 2019 4:54 pm

Re: Question on Leitz objectives

#6 Post by geo_man » Mon Oct 21, 2019 1:11 pm

Thanks all. I decided to return the 2.5x objective. I had the second problem that one of the centering screws on my unused opening seemed to be stripped so I couldn't properly center it. No big deal as I still have 4 good properly centered objectives with a good range.

I also purchased lower power / wider field eyepieces so I expect to improve my overall FOV as desired (I had 12.5x periplans, I bought 10x periplan GFs). Should receive them today. I have a 1.25x tube lens system.

Thanks again!

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