Leica lens experts - is this a "dipping" lens?
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Leica lens experts - is this a "dipping" lens?
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
Thanks,
Leica PL Fluotar 20x/0.45 D Inf/0
Thanks,
-Gene
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??
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
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.Pau wrote:IMO it's a BD lens with the outer shell removed (but not a Leica expert at all)
-Gene
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...
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...
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.
Thanks Chris, I hadn't seen that brochure before.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 ! ...
'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
A thought - we recently saw a "DI" objective : http://www.photomacrography.net/forum/v ... =objective
Chris R
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.
and here's another view of the Leica objective (I can't discern the shape of the lens from the photo):
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.
Here's a photo of a water dipping Zeiss objective with similar appearance.
and here's another view of the Leica objective (I can't discern the shape of the lens from the photo):
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
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.
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.