I still can’t seem to get dark field to work well!
Photos below using infinity-corrected 50x objective with iris diaphragm, curves adjusted in GIMP2.
Algae from my pot pond 12/4/2018:
Volvox on commercial slide viewed by myself today using same setup as above:
Over this last week I have created a temporary aquarium from pond water plus the Elodea pond weed I have been using in my previous posts this weekend. On various microscope blogs, it is recommended that slides are left in aquaria to see what grows on them….so I left a few in this one last night and the photos and video below are from one of those slides. Note that the organisms on this slide are directly growing and living on the slide so are unaltered. This is a live sample without any staining or centrifuge etc. Therefore the Helicon Focus 3D model below is probably the first as in vivo (because it is in vivo) model of a sphere of cells that I have obtained.
Today was also another chance to have a go at dark field microscopy and for the first time I used COL (circular oblique lighting). Still having problems with the dark field which I suspect is due to relative numerical apertures of condenser and objectives but COL was quite successful as you can see below – this uses an off axis one-sided aperture mask for the condenser.
Temporary aquarium – notice the frog’s eggs!
x10 Objective Bright Field
x10 Objective Dark field:
x20 Objective Bright Field:
x32 Objective Bright Field:
x63 Objective Bright Field:
Helicon Focus 3D model of above organism (ball of cells):
x40 Objective Circular Oblique Lighting (COL) – note in COL the apparent differences in 3D height are contrast differences and do NOT reflect actual contour changes in elevation on the slide (below):