Joel Lode has done quite a bit of Cactus seed photography as has Dr Detlev Metzling. Problem can be it often comes somewhere between low magnification microscopy and higher magnification macro photography. Also these days of digital photography, either using a microscope or with macrophotography you need to focus stack to get all seed in focus. In the old days with film you were restricted to merely balancing reasonable depth of field against diffraction and putting up with a softer image to get more in focus, since focus stacking only came about with digital photography and computers.
Scroll down this link.
http://cactus-aventures.com/Taxonomy/Td ... ctENG.html
Some of Detlev Metzings here:-
http://forum.bcss.org.uk/viewtopic.php? ... 0&start=10
I am in the preliminary stages of setting up to do some pictures of seed for a friend using a macro setup. He is using a microscope too but says the magnification is too much for what he wants as he often wants more than one seed in shot, but a small group with one standing on end to show the hilum.. This was just a quick test to see if I could manage to set the pin head sized Thelocephala seeds to stand up on double sided Sellotape. But as I have had flu at the moment so not being able to see tiny seed with bleary eyes it will have to wait a week or so until I am back to normal.
The idea is the setup in the picture below with a milk white diffuser made from a plastic bottle neck lit by two flashguns and then do around a 12 image focus stack using the StackShot rail at the back that can automatically move the camera in sub millimeter increments if needed. Camera goes on right top but had to use it to take the picture.
- seed-setup.jpg (119.68 KiB) Viewed 2817 times
These were just preliminaries used to see if I could get the magnification required and obviously focused a little too far in to start. Different background colours may be used but of course any background colour can be changed in post processing anyway. I am just proceeding one step at a time to refine the setup. Of course at these magnifications you cannot stop down far as in normal macro photography since diffraction rears it's ugly head, softening the image and the lens had to be used around f8-f5.6 and the image focus stacked. Must be a doddle photographing something as large as Opuntia seed compared to Thelocephala's, and Aztekium's would be even worse but then a microscope would be better, but you would still probably need to focus stack to get all of the seed in focus at once in the picture.
These have not been focus stacked since that would have had all the seed in focus, they are just a single trial shot which shows how small the depth of field is with a seed only a couple of millimetres in diameter. At those magnifications the depth of field can often only be as deep as the thickness of a piece of writing paper.
- seedRMF2.jpg (114.76 KiB) Viewed 2817 times
- seedx.jpg (96.46 KiB) Viewed 2817 times
Any ideas how to clean the brown material off such tiny seeds.
For those who do not know what focus stacking is and why often at higher magnifications enlarger lenses as on my setup can be better than a normal macro lens see:-
http://extreme-macro.co.uk/focus-stacking/
Now you know why many try it and give up!
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