Field Microscope
assembled field microscope on the stage platform along with a number of accessories arranged in front of it. These include a substage condenser lens, polarization filter, and darkfield Rheinberg filter—anything that can be mounted on a 1 3/4" metal washer and placed in the well surrounding the central light hole.
Figure 7 : Field microscope with Amscope MU300 digital eyepiece camera, shown attached to a laptop computer via a USB cable.
Also pictured are various lighting arrangements, including oblique epi-illumination provided by the attachable fl ashlight (very helpful for surface examination of opaque or thick specimens like sand or wood), but also LED and available transmitted light sources from below the stage. T is exceeds the requirement outlined in criteria #6 and #7. Easily and quickly assembled and dismantled, all this and much more can be fit into a convenient carrying case like a camera bag or the CD/DVD bag pictured in Figure 5 . I have packed a 1/2 gross box of standard 1" × 3" glass slides and 23 mm square coverslips in this field case along with dozens of other specimen-collecting and holding devices, like 2" × 2" plastic baggies with zippers, small plastic capped centrifuge tubes, plastic Pasteur pipettes, small bottles of isopropyl alcohol, and lens cleaner. The whole 10" × 8" × 5" (24 × 20 × 12 cm) case fully loaded weighs 5 lbs (2.3 kg), and it has a shoulder strap for easy carriage in the field. I have passed through the security check points of many airports with this field kit, and while it inevitably gets me pulled aside for questioning (“What IS this thing—a drill?”), it has never caused a serious problem or delay in getting to my scheduled flight on time.
Figure 8 : Example images of sand grains from Wyoming taken with the shop-inspection fi eld microscope. Clockwise from upper left: sub-stage transmitted light, oblique epi-illumination, cross-polarized light, cross-polarized light with wave plate (cellophane wrap). All images were taken with an Amscope eyepiece camera and 10× objective. Image width = 1.0 mm.
mirror on a wooden mount that can be positioned between the legs for use with available light, as shown in Figure 4 below. Accessories . The versatility provided by accessories to this setup increases its utility in the field. Figure 4 shows the
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Smartphone light sources . I recently discovered a free application (“app”) written for the purpose of turning a smartphone or tablet into a fl ashlight or “torch” to fi nd things in the dark. What is interesting from a microscopy point of view is that this app allows the user to adjust not only the brightness of the screen-sourced light, but also to choose an enormous range of colors, also adjustable for intensity. If used as a light source with the fi eld microscope and stage described above, an amazing range of lighting is made possible. T e arrangement is illustrated in Figure 6 . To make use of this app, the platform stage, without legs attached, can be set directly on top of a smartphone or tablet. I have used it
quite eff ectively with my Kindle Fire. Some electronic phones and tablets (including the Kindle Fire) even come with a screen that provides linearly polarized light. T is can be used with the other non-white colored background light choices, giving a huge range
www.microscopy-today.com • 2015 July
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