Leica lens experts - is this a "dipping" lens?

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

Moderators: rjlittlefield, ChrisR, Chris S., Pau

genera
Posts: 127
Joined: Wed Oct 05, 2011 5:05 pm
Location: California, USA

Leica lens experts - is this a "dipping" lens?

Post by genera »

Is this a lens for direct dipping (sorry, I don't know the correct term) into a petri dish? Can you tell me anything more about it?

Leica PL Fluotar 20x/0.45 D Inf/0

Image

Thanks,
-Gene

Pau
Site Admin
Posts: 6038
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

IMO it's a BD lens with the outer shell removed (but not a Leica expert at all)
Pau

ChrisR
Site Admin
Posts: 8662
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

In this brochure, water dipping ones have an L, not a D . It doesn't have any BD's , or D's though.:
https://www.leica-microsystems.com/file ... ure_EN.pdf


elsewhere:
" is the ‘water-immersion’ objective, usually abbreviated as ‘WI’ or ‘W’ on the barrel of the objective. "

I can find BDs with BD, and also with L ! ...

Decent list HERE but no 20/0.45s...
https://phenogenomics.dentistry.ubc.ca/ ... ves_EN.pdf

Suggest D = darkfield -if there's an annulus for the light to come down??
Last edited by ChrisR on Sun Dec 23, 2018 4:36 pm, edited 1 time in total.
Chris R

genera
Posts: 127
Joined: Wed Oct 05, 2011 5:05 pm
Location: California, USA

Post by genera »

Pau wrote:IMO it's a BD lens with the outer shell removed (but not a Leica expert at all)
Thanks Pau. I should have posted more photos. There is no light path to the rear of the objective. The black material extends all the way to the outer diameter at the bottom of the brass ring and there are no threads.
-Gene

ChrisR
Site Admin
Posts: 8662
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

We crossed while I was editing. A bit of a mystery then.
Judging by the diameter of the front glass and the NA, the WD wouldn't be very long?
Chris R

Beatsy
Posts: 2102
Joined: Fri Jul 05, 2013 3:10 am
Location: Malvern, UK

Post by Beatsy »

My first thought was epi objective with the outer shell removed. But from what you've subsequently said - that's clearly not the case.

But every kind of immersion objective I've seen has the front element flush with the metalwork, not recessed like that one (although some higher power ones can have a concave front element, the edges are still flush with the end of the barrel). Presumably to support easier cleaning. This makes me think it's not designed for "dipping". Not sure about that though, just speculating...

Lou Jost
Posts: 5933
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Post by Lou Jost »

Genera, just to clarify what you said, what does the back of the objective look like? It sure seems like the tip has the shape of a BD objective...but with the light guide inside the black tube.
Last edited by Lou Jost on Sun Dec 23, 2018 5:55 pm, edited 1 time in total.

JohnyM
Posts: 463
Joined: Tue Dec 24, 2013 7:02 am

Post by JohnyM »

It is epi darkfield objective. D stands for "dunkelfeld" which is german for darkfield.

genera
Posts: 127
Joined: Wed Oct 05, 2011 5:05 pm
Location: California, USA

Post by genera »

ChrisR wrote:In this brochure, water dipping ones have an L, not a D . It doesn't have any BD's , or D's though.:
https://www.leica-microsystems.com/file ... ure_EN.pdf


elsewhere:
" is the ‘water-immersion’ objective, usually abbreviated as ‘WI’ or ‘W’ on the barrel of the objective. "

I can find BDs with BD, and also with L ! ...
Thanks Chris, I hadn't seen that brochure before.

'W' or 'WI' is what I would expect. I think I've also seen 'H' or 'HI' (for H2O) used on another brand. But, in Leica world, 'HI' means something else.

I think the lone 'D' on the objective calls out the DIC/ICT prism needed above the objective. Leica uses that location, immediately after the aperture, for that purpose. The 'L' is for long working distance, a characteristic that's needed if it is meant for dipping.
-Gene

ChrisR
Site Admin
Posts: 8662
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

A thought - we recently saw a "DI" objective : http://www.photomacrography.net/forum/v ... =objective
Chris R

genera
Posts: 127
Joined: Wed Oct 05, 2011 5:05 pm
Location: California, USA

Post by genera »

There is no light guide inside the tube. The tube is completely blocked by the ceramic ? substance.

Here's a photo of a water dipping Zeiss objective with similar appearance.
Image

and here's another view of the Leica objective (I can't discern the shape of the lens from the photo):
Image

The 'D', I'm fairly certain, represents the back focal plane position for the objective which must be known in order to select the correct DIC prism. There are 5 options: A through E each representing one of five BFP positions. Leica uses 'BD' for dark field objectives and, as far as I can tell, all of them have M32 barrels. This one is M25.

If I can't get find anything definitive I may try a vacuum leak test, at a very low differential pressure, to see if it's sealed.

Thanks everyone for your suggestions.
-Gene

Lou Jost
Posts: 5933
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Post by Lou Jost »

I still would really like to see the back of the objective. It looks like the ceramic thing could have a light guide inside it. It might not be obvious though.

ChrisR
Site Admin
Posts: 8662
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

The first pic does make it appear there's a depression - which would make an air pocket?
Chris R

genera
Posts: 127
Joined: Wed Oct 05, 2011 5:05 pm
Location: California, USA

Post by genera »

ChrisR wrote:The first pic does make it appear there's a depression - which would make an air pocket?
It does look that way. I should have it in a week or so.

Another point against water dipping is that there's no white band.
-Gene

Lou Jost
Posts: 5933
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Post by Lou Jost »

Again, it really looks as if there is a light guide INSIDE the black ceramic. I suspect there is indeed a light path there, gathering the light from the back lens of the objective rather than from a discrete BD annulus. Or perhaps there is a reflective surface inside there and ordinary epi light gets spread onto the subject. JohnnyW's comment above also suggests something like these alternatives.

It would be useful to shine a directional light straight through the front of the objective and see if there is a darker ring showing around the edge of the back lens of the objective.

Post Reply Previous topicNext topic