Using my Optiphot microscope for stacking, the available APO lenses have very short WD. So for this Christmas my wife gave me an infinity 40X 0.60 ELWD with a correction collar and a WD of 3.7-2.7 mm.
This is an interesting lens, the correction collar makes it possible to look into glass with a thickness of up to 2 mm, I have already taken a close look into some of my amber pieces.
After testing I have found out that the best set up with the gear that I have is to use a 150mm tube lens and 2.5 PL lens so aprox 75x on sensor (150/200*2,5*40).
The first picture is my new favorite test subject; a wing from a Common blue.
This is a fluor and there is some -I think- longitudinal CA. Almost all of the purple and green CA disappears in PMax stacking. When I do no alignments the results seem to be even a little better. But for some subjects there are some remaining purple color areas. I have tried to do some CA removal in LR prior to stacking but with little succes. To little adjustment and the CA remains, to much and there are gray/brownish areas instead.
Today I tried some of the filters that I have (yellow plastic, a long pass 510nm, a NCB 14 filter, sunglasses and the green filter that came with the microscope. The green filter came out "best" no CA (with my eyes) and some more sharpness. But difficult to restore colours. The second picture below shows a test with an ant, 100%, the left picture is ordinary EPI light no polarisation, the right picture is the same setup but with the green filter, WB in camera, HUE and Saturation, after stacking.
Maybe a longpass filter that starts before 510 nm will be better?
So now to my question - have anyone tried some other filters to handle CA - succesfully or not?
Regards Jörgen
NORMAL EPI_________________________________________________________EPI and GREEN FILTER
