https://www.photomacrography.net/forum/ ... sc&start=0
I proposed using reversed Micro Four Thirds lenses on tube lenses to shoot subjects through water at low magnifications (1-8x). Micro Four Thirds lenses work well for this, because they are designed to send their image through a thick sensor filter pack about 4.2mm thick. That mean that when they are reversed, they are corrected to shoot through 4.2mm glass or 4.8mm water, (the optical equivalent of that much glass). There should be a "tolerance range" of a few millimeters centered on this depth, and this tolerance range will be a function of NA. The advantage of using a lens that is corrected to shoot through a thick medium is that we can take advantage of both the + and - sides of this tolerance range. A lens with the same NA but corrected for zero medium thickness will only have half the usable range of depths.
I'm putting these ideas to work now in my orchid research. I have had excellent results with the Panasonic 42.5mm f/1.7 and the Olympus 75mm f/1.8, both reversed on a Mamiya Apo medium format 200mm lens on the Panasonic S1R FF camera. Here is an example using the latter lens, for m=2.6, at f/3.2. This is an undescribed Teagueia orchid I am currently describing:
All parts are sharp, from the most shallow (that organ sticking up from the center) to the deepest (the recurved sepal and petal tips). Here is a 100% crop of the tip of the flower:
Here is another new species using the 42.5mm lens at f/3.2 for m=4.6:
I am very happy with these! The flowers are so thin and fragile that they collapse within minutes after being cut if left in air. Now I can photograph them as much as I want.
