Condensor question please?

[Gasman]

Hi guys
I have a Leitz Laborlux S which I recently converted to LED which came with this condensor (without filter slot) with a flip up lens.

LK.jpg (12.1 KiB) Viewed 2206 times

I want to try Rheinberg and Darkfield illumination and acquired this condensor which can accomodate filters and arrived today.

56.jpg (6.67 KiB) Viewed 2206 times

I did wonder whats to choose between condensors (apart from the filter capacity) as this new 56 condensor has no flip up lens so presumably fine for all magnifications whereas the LK one needs the flip up lens for mags greater than x4?
regards
Steve

[apochronaut]

Your new condenser says A 0.90 on it which means it is good as a general purpose condenser for most objectives. It is usefull because it is not designed to be used with oil, so it is convenient . However , having a maximum N.A. of .90 , it limits the resolution of higher N.A. objectives that require oil or other immersions. Usually , the reduction is not great with objectives up to 1.25.
wc
The flip top condenser has a reduced N.A. when the top lens is in the down position, so it is designed to accomodate both higher magnification objectives if the lens is up and oiled, as well as low magnification objectives when the lens is down. The .90 N.A. condenser with it's fixed top lens may not fill the field with light when used with low power objectives (usually about 5X and under but I am not sure about Leitz). They are designed to take an aux. lens for that purpose, which fits under the main condenser.

[Gasman]

Excellent thanks for the info, very helpful. I did wonder what the 0.9 referred to!
Steve

[apochronaut]

I'm glad you got it, because I didn't when I reread it. That must have been written with my right brain, while I mopped up spilled coffee with the left.
I edited it a bit and put the objectives and condensers in their correct places.

[Gasman]