I print these at 12 x 18 inches, and the tachinid fly in the first image is about 1/2 inch long or so. That should give you some idea of the magnification. I keep meaning to include scale bars, but haven't yet because I'm having too much fun just shooting the specimens. The specimens themselves are pin mounted, standard insect specimens. I clone out the pins during post processing. I'm very fortunate to maintain a university entomology teaching collection, otherwise known as a job responsibility I'm not paid for.
The images are focus stacked. The first image in this post, the tachinid fly, is comprised of 31 separate exposures on successive focal planes. I use a vertically mounted camera with specimens on the table beneath it to shoot these dorsal views. I light the specimens with two remote triggered speedlite flashes and duel fiber optic microscope illumination. I use Helicon Remote to control the camera (a Nikon D7200) and take the focus stacked images. The lens is a somewhat old autofocus Tokina 100mm f2 8 macro, which yields 150mm on my APS-C sensor. I'm loving that glass. I also add a Raynox 150 close up adapter and occasionally use extension tubes to increase the magnification. The tachinid fly photo used the Tokina 100mm and the Raynox 150, but no extension tubes.
After shooting the stack, I combine the stacked images into a single sharp, composite photo with Helicon Focus. Then it's the usual post processing workflow with Lightroom and Photoshop. I have to spend lots of time cloning out dust and other crap on the specimens, some of which have been handled by students for decades. I use Nik filters to refine the images in Photoshop.
I hope this has been helpful. Macro and close up photography is a bottomless rabbet hole. I'm not sure I'd have dived into it without this incredible resource-- the university entomology collection--but I really like it and hope to expand my photos into a couple of related directions.