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Dear Confocal list,


I'm about to roll out an update for my Android app, "Resolution", which some of you were kind enough to download when I published it late last year.


The original version was really designed around fluorescence microscopy, it only gave the user the option to enter a single NA, and it calculates resolution using the following version of Abbe's equation:


Res = 1.22 lambda / 2NA


I thought it would be helpful to add the ability to characterise a transmitted light objective, with a distinct condenser NA and objective NA, and to calculate resolution based on the following version of the equation:


Res = 1.22 lambda / NA (obj) + NA (condenser)


My original thought was to just implement this version of the equation exactly as it is, a let the user freely enter the two NAs, and do the calculation.  However, my understanding is that this version of the equation really only applies when the NA of the objective and the NA of the condenser are equal.  Under circumstances in which they are unequal, the true resolution would be:


Res = 1.22 lambda / 2  NAmin


Where NAmin = the smallest NA of the condenser and objective.  In such cases resolution is constrained by the smaller of the two NAs.


This is pretty much what I've implemented, but I don't have the confidence to release this without first checking with this list that this is the right approach.


If you could share your thoughts on this I'd be very grateful.


If anyone would be interested in taking a look at the beta of the next version I'd be happy to share it with them.


Many thanks,


Andy Barlow