www.photomacrography.net :: View topic - Olympus LM PLAN FI 20x/0.40 BD infnity corrected
www.photomacrography.net Forum Index
An online community dedicated to the practices of photomacrography, close-up and macro photography, and photomicrography.
Photomacrography Front Page Amateurmicrography Front Page
Old Forums/Galleries
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Olympus LM PLAN FI 20x/0.40 BD infnity corrected
Goto page 1, 2  Next
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Equipment Discussions
View previous topic :: View next topic  
Author Message
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Fri Feb 14, 2020 8:29 am    Post subject: Olympus LM PLAN FI 20x/0.40 BD infnity corrected Reply with quote

Hello,
anyone can give me some information about this please?



Thanks
Antonio
Back to top
View user's profile Send private message Visit poster's website
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3431
Location: Ohio, USA

PostPosted: Fri Feb 14, 2020 9:00 am    Post subject: Reply with quote

From off-line communication, I understand that Antonio wants to know if this objective is suitable for use on a macro rig. For example, does it require CA compensating optics? What is its working distance?

--Chris S.
Back to top
View user's profile Send private message Send e-mail
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Fri Feb 14, 2020 9:27 am    Post subject: Reply with quote

Chris S. wrote:
From off-line communication, I understand that Antonio wants to know if this objective is suitable for use on a macro rig. For example, does it require CA compensating optics? What is its working distance?

--Chris S.

Thanks Chris S. Smile
I found this topic in another website: https://foromacrosmuymacros.com/viewtopic.php?f=12&t=858

Antonio
Back to top
View user's profile Send private message Visit poster's website
Ichthyophthirius



Joined: 07 Mar 2013
Posts: 933

PostPosted: Fri Feb 14, 2020 1:47 pm    Post subject: Reply with quote

Hi,

Have a look at the Industrial Component Guide, p. 17: https://www.olympusamerica.com/seg_industrial/files/industrial_component_guide.pdf
Working distance is 12mm, thread is M26 x 36 TPI, FN is 26.5.

https://www.edmundoptics.eu/p/olympus-lmplfln-bd-20x-objective/29238/

Olympus UIS/UIS2 objectives need no additional CA correction in the tube lens. You just have to find a suitable tube lens. Olympus tube lenses (U-TLU; single port tube with lens, p. 3) are regularly sold on Ebay.

Regards, Ichty
Back to top
View user's profile Send private message
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3431
Location: Ohio, USA

PostPosted: Fri Feb 14, 2020 2:43 pm    Post subject: Reply with quote

Ichthyophthirius wrote:
. . . need no additional CA correction in the tube lens. You just have to find a suitable tube lens.

Excellent!

Antonio, you already have a suitable tube lens, as I know you have an assembly based around the Raynox DCR 150, which we now know will work fine with this objective. Just be aware that this nominally 20x objective will deliver a bit over 23x magnification on your sensor when used with the Raynox.

(Why? Because the Olympus objective is designed to deliver 20x magnification with a 180mm focal length tube lens; your tube lens has a 208mm focal length; and magnification on sensor scales with focal length of tube lens. The math is: 208mm/180mm * 20x = magnification on sensor .)

Also be aware that you will need the proper adapter for your Raynox assembly. Since Ichty reports that the Olympus BD objective takes M26x36 TPI threads (the same as used by Mitutoyo objectives), you can look for either an Olympus BD adapter or Mitutoyo adapter that fits the front of your Raynox assembly. (TPI means "Threads Per Inch", or 0.706mm.)

Lastly, since this is a BD objective, there will be an outer ring that must be blocked to prevent light from leaking onto your sensor. This should be easy to do.

--Chris S.
Back to top
View user's profile Send private message Send e-mail
Ichthyophthirius



Joined: 07 Mar 2013
Posts: 933

PostPosted: Fri Feb 14, 2020 3:46 pm    Post subject: Reply with quote

Yeah, also note that the distance between objective and tube lens is "50 mm to 170 mm" with the U-TLU tube lens. If the objective doesn't perform well with the Raynox initially, vary the distance between objective and Raynox to find the optimum configuration.

Regards, Ichty
Back to top
View user's profile Send private message
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Sat Feb 15, 2020 1:14 am    Post subject: Reply with quote

Thanks Ichty and Chris S. Smile
Tomorrow morning i will go to get the objective Smile
Antonio
Back to top
View user's profile Send private message Visit poster's website
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Sun Feb 16, 2020 9:23 am    Post subject: Reply with quote

Hello,
I just bought the lens (120 euro). 50X was sold past days.
It looks in perfect condition, my friend detached it from his microscope. Now I have to figure out which adapter to buy for my kit with DCR150.
I hope upload test photos next days (if lens works!)
Antonio
Back to top
View user's profile Send private message Visit poster's website
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Mon Feb 17, 2020 2:21 am    Post subject: Reply with quote

Hello Chris S., about this you said :
Quote:
..there will be an outer ring that must be blocked to prevent light from leaking onto your sensor...

what does it mean "blocked"?
I must insert dark material to prevent light?
Thanks
Antonio

Chris S. wrote:
Ichthyophthirius wrote:
. . . need no additional CA correction in the tube lens. You just have to find a suitable tube lens.

Excellent!

Antonio, you already have a suitable tube lens, as I know you have an assembly based around the Raynox DCR 150, which we now know will work fine with this objective. Just be aware that this nominally 20x objective will deliver a bit over 23x magnification on your sensor when used with the Raynox.

(Why? Because the Olympus objective is designed to deliver 20x magnification with a 180mm focal length tube lens; your tube lens has a 208mm focal length; and magnification on sensor scales with focal length of tube lens. The math is: 208mm/180mm * 20x = magnification on sensor .)

Also be aware that you will need the proper adapter for your Raynox assembly. Since Ichty reports that the Olympus BD objective takes M26x36 TPI threads (the same as used by Mitutoyo objectives), you can look for either an Olympus BD adapter or Mitutoyo adapter that fits the front of your Raynox assembly. (TPI means "Threads Per Inch", or 0.706mm.)

Lastly, since this is a BD objective, there will be an outer ring that must be blocked to prevent light from leaking onto your sensor. This should be easy to do.

--Chris S.
Quote:
Back to top
View user's profile Send private message Visit poster's website
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3431
Location: Ohio, USA

PostPosted: Mon Feb 17, 2020 2:42 am    Post subject: Reply with quote

anto74 wrote:
Hello Chris S., about this you said :
Quote:
..there will be an outer ring that must be blocked to prevent light from leaking onto your sensor...

what does it mean "blocked"?
I must insert dark material to prevent light?

Antonio,

Congratulations on acquiring what looks like a very nice lens at a favorable price.

In general, BD lenses (the letters stand for "Brightfield/Darkfield") have an outer barrel and an inner barrel. The inner barrel contains the glass elements of the lens. The outer barrel is hollow, and was intended to conduct light onto the subject (when used on a brightfield/darkfield microscope) from a light source on the microscope, shining through this outer barrel, onto the subject.

In your use, no such light source exists. And worse, this hollow outer barrel can permit light that bounces off the subject, or areas around the subject, to travel up this outer barrel and shine on your sensor. So yes, you must block this outer barrel to keep stray light from fogging your sensor.

Quote:
I must insert dark material to prevent light?

That would be one way to do it, and I can think of other ways. This said, I've never had a BD objective in hand, so have not personally blocked this source of light leakage. But many other members of our forum have done this, and I would ask how they have done it.

Can folks who have experience in blocking off the outer barrel of a BD objective give Antonio practical advice?

--Chris S.
Back to top
View user's profile Send private message Send e-mail
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Mon Feb 17, 2020 12:52 pm    Post subject: Reply with quote

Thanks again Chris S. Smile

Now I'm testing the lens (only for testing I used insulating tape...) and I will post the shot.

Two questions:

1) I must block the light in outer ring near the subject or near the mount lens?

2) This objective has 180mm tube lens distance. I have variable kit lens purchased on Mjzkk website. I must calculate the tube length + Raynox DCR 150 length or I must consider only tubes length? 180m are only tubes or tube + DCR150?

Thanks,
Antonio

PS Sorry for my stupid question...but I'm learning...
Back to top
View user's profile Send private message Visit poster's website
Antal



Joined: 28 Sep 2012
Posts: 48

PostPosted: Mon Feb 17, 2020 1:53 pm    Post subject: Reply with quote

Ciao Antonio,

Basically you will set your tube lens focus at infinity. Therefor you focus with your tube lens (without any microscope lens! just the Raynox) on a very distant object.
Your raynox is now set at little more than 200mm. This will give you a little more than 20x mag with the olympus.
In a second step you just have to try out, make some testing reducing distance between sensor and TL. Some people have showed that some objectives work better with reduced distance sensor-TL..

Have fun with your lens!

Edit: Nominal focal length for the raynox seems to be 208mm
And: read mtf testing of the raynox here: https://www.photomacrography.net/forum/viewtopic.php?t=41049
_________________
www.antalthoma.ch
Back to top
View user's profile Send private message Visit poster's website
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 8470
Location: Near London, UK

PostPosted: Mon Feb 17, 2020 3:21 pm    Post subject: Reply with quote

I have a couple of BD objectives with black rubber "O" rings blocking the light path (threaded end). Easy to use and work.
_________________
Chris R
Back to top
View user's profile Send private message
anto74



Joined: 06 Feb 2020
Posts: 27
Location: Italy

PostPosted: Fri Feb 21, 2020 7:00 am    Post subject: Reply with quote

Thanks Antal and ChrisR Smile
Antonio
Back to top
View user's profile Send private message Visit poster's website
Antal



Joined: 28 Sep 2012
Posts: 48

PostPosted: Fri Feb 21, 2020 6:37 pm    Post subject: Reply with quote

Haha, we want to see results!
_________________
www.antalthoma.ch
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Equipment Discussions All times are GMT - 7 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group