Dear Aryeh,

We regularly use a 20x LWD on our IX81 without any problem. You should 
be aware that the working distance of a LWD objective is several mm, so 
you need to be considerably further away from your sample compared to 
high-NA imaging. Eventually you simply need to lower your objective 
(using the focus wheel). if you can't lower your objective enough (to 
have a proper image) then eventually a focus-limit has been 
set/activated on your microscope.

Cheers    Gabor

> I am a problem imaging with  the Olympus LWD (long working distance) 
> objectives on an IX81 frame. I have image well with the  high NA 
> objectives (oil and air),
> which are used when imaging through thin coverslips. However, with the 
> LWD objectives, I cannot raise the turret enough to get an image.
> This is puzzling, because I thought that the objectives were designed 
> to be parfocal, so that if I have focus for one objective, I will have 
> focus for the other at the same turret position. Yet, if I put a 
> regular slide with a coverlip on the scope, I can image it with the 
> 20x close focus air objective, but then when I switch to the LWD 
> objective ( and set the cover thickness ring appropriately for a 
> coverslip, I cannot even get close to an in-focus image.
>
> The stage is a LUDL motorized stage, and it may be higher than the 
> regular mechanical stage, but this does not explain why the close 
> focus high NA objectives can focus, and the LWD objective dont.
>
> Thanks in advance  for putting me straight on what is probably 
> something obvious.
>
> --aryeh


-- 
Gabor Csucs 
Light Microscopy Centre, ETH Zurich
Schafmattstrasse 18, HPM F16 
CH-8093, Zurich, Switzerland

Web: www.lmc.ethz.ch
Phone: +41 44 633 6221
Fax: +41 44 632 1298
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