I think the Omax Kohler is a field lens assembly:blekenbleu wrote: ↑Sat Jul 02, 2022 12:04 pmA field diaphragm improves image contrast by blocking stray light,Dubious wrote: ↑Sat Jul 02, 2022 5:31 amIt's interesting that Omax and Euromex sell add-on field diaphragms--apparently someone thinks Kohler illumination is worthwhile even on lower end scopes. A pity, though, they didn't just incorporate a field diaphragm into the original design. Probably would have added all of $5 to the manufacturing cost...
which may be more problematic in lower end scopes.
If, as it seems, these diaphragms are added between field lens and condenser,
then they cannot be at an illumination focal plane unless extra lenses are also involved.
https://omaxmicroscope.com/a195k-kohler ... copes.html
and https://omaxmicroscope.com/UserManuals/M93SBDK.pdf
although just the field iris part is available as a separate spare.
The Euromex iScope comes with the Kohler fitted but the diaphragm part is available as an accessory (spare?)
See data sheet:
https://www.euromex.com/en/products/pro ... es/iscope/
Re accessories: I only know what I've seen advertised. Maybe someone else on here has bought one? However, the 'Kohler' field iris on my Amscope T720Q appears to be the same field iris as on the Euromex iScope above. Without undoing it, I don't know exactly what lies beneath. I'm thinking maybe that scopes like the T720 that come with diffused LED are cheating a bit with their 'Kohler' designation. But, inasmuch as they allow focusing on the diaphragm via the condenser height adjustment on the field iris (as in my short youtube video above), they perhaps achieve the same outcome as a more complicated lens assembly and which may use a halogen bulb.
I'm no expert on the optics of Kohler but it's just my sense of things. I'm open to correction and others wisdom on this!
Louise