Hello,
I was wondering if any of you have a rough estimate on the specs for Plan-APO objectives when imaging for instance using a 488 and 633 nm laser.
Basically what is the best possible values one could achieve in XY and Z overlap (given the right immersion, embedding etc) with respect to the size of the PSF.
The companies often give a qualitative statement but no real numbers.
Thanks
Antonio
This website has examples of axial chromatic shift in lenses with apochromatic (3 colors) and super-apochromatic (4 colors) corrections:
Lenses with identical specifications will show different chromatic shifts, so it makes sense to get several lenses for testing and keep the best one.
Thanks.
What I found out is that the norm is specified in the ISO 19012-1:2013 which you need to buy in order to read it. I think it only defines the Z-offset. Typically, good Apochromat objectives overfulfil the norm.
Antonio
I wrote this ages ago! (https://www.microscopyu.com/pdfs/Drent_Micro_and_Analysis_19-5-2005.pdf) Many things have changed since then. Chromatic correction is still the same. Interestingly the focus on chromatic correction has shifted in 15 years from UV to (Near) Infra Red. Also NA’s have been increased since then, resulting in a need of even more stricter chromatic corrections.
Greetings, Peter
Hello,
I kind of revive this thread. Recently, I went through the ISO-APO specification and I realized that there is no XY specification! The ISO Apo norm only seems to specifiy in dependence of NA and wavelength the axial correction.
So an APO objective can be excellent axially but really bad in XY and you have no way to complain. We just had such a case, we think it was a combination of objective and poor correction within the tube-lens. The offset a little outside of the field-of view was > 1 PSF FWHM.
Antonio