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Hallo,
I would appreciate a pointer to a paper or a book chapter that provides the 
theoretical background/explanation for the fact that a DIC prism will degrade 
resolution of the fluorescence image. My search in archives of this list brought 
up quite a few discussions on this topic, but I was looking for a more 
theoretical treatment of the issue.

I have a little puzzle with our Fluoview FV1000 system  (for those not familiar 
with Olympus setup: these is a single DIC prism behind the objective; the 
condenser turret then has several different DIC prisms, specific to each 
objective - but that is not relevant for epifluorescnece).
A expected, having the DIC prism behind the objective degrades the confocal 
image with all objectives, but surprisingly the degradation is much worse with 
our 20x/0.85 oil than is with the 60x/1.2 WI or 100x/1.4 oil objectives. I 
expected the opposite, the amount of shear introduced by the prism (a 
fraction of a micrometer) should have been more noticeable with higher 
resolution objectives.  It makes it very easy to demonstrate the effect of DIC 
prism on confocal image quality to new users during training, but I would sure 
like to know what is happening.
 
The second puzzle is that inserting the DIC prism in the optical path causes a 
shift in focus (at least several micrometers, very noticeable). In my naive 
thinking, I assumed that inserting a flat piece of glas at normal orientation into 
the infininty space would not cause any focus shift, at least for imaging 
sample area close to the center of the optical axis.
Any ideas?  

I am in discussion with Olympus and thay are very receptive, but I thought I 
would ask here as well.

 Thanks in advance!

Stan Vitha
Microscopy and Imaging Center
Texas A&M University
College Station, TX