Since I described my new panorama head in yesterday's blog, I decided I would show where my snowflake setup is going. I have tried at least six different microscope systems with varying degrees of success. Although they all "work" in that I can get relatively decent images, they all seemed a bit complex and were difficult to set up and use. I finally decided to try the extension tube technique that Kenneth Libbrecht describes in the
Snow Crystals.com site. Libbrecht uses a microscope objective and extension tubes from Edmund Optics, but I decided that I could surely come up with the equivalent with the junk I had lying around. I finally settled on a bellows made for a Pentax camera, and for a lens I am using a Pentax-A 1:4.7 - 5.6 80-200 mm lens from my "junk pile". I made an adapter that allowed the Pentax fittings to work with the Nikon body. To keep things simple I just use my tripod to hold the camera in a vertical position.
The sample platform is a rebuilt "Lab Jack" that can be easily moved or adjusted. A glass plate is clamped to the lab jack, and two high intensity LED lamps provide basic illumination. One thing I did add was a "tilt plate" which allows stereo images to be photographed. The 4 x 4" plate tilts on two 3/32" aluminum dowels taped to the primary glass plate. If the snowflake is placed on the upper plate and properly aligned, it is trivial to take the two photos necessary to generate a stereo image. One nice thing about the setup is that only the sample platform needs to be left outside to cool down. The camera and tripod assembly can be put together and turned on inside and then simply moved outside when the snow flies!
The first few snowflakes that I have looked at were terrible (where is the snow when you need it!), so I took a few photos of some salt crystals to see how the stereo works. As shown in the images below, it appears to be quite satisfactory!
The last image, below, shows that it is even possible to see the depth in a quarter!
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