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Getting very close - Part 3

by Christopher Algar

When I began looking into buying a microscope with which to take photographs, I was overwhelmed with the complexity of the subject. My only previous experience with microscopes was in the days when most were of the monocular type and digital photography and stacking of images were in the distant future. Rather than give up, however, I have tried to extract information from various sources pertinent only to our own requirements.

One method of taking photographs through a microscope is to hold a camera with an attached lens close to one of the eyepieces. This seems similar to using binoculars instead of a telephoto lens for distance photography to me and it is not something that I have tried. Another method involves using a trinocular microscope, which has a tube for attaching a camera in addition to the usual binocular eyepieces. A proportion of the light can be switched over to this tube and, with the addition of a photo eyepiece and a camera adapter, the microscope can be used for photography.

When we finally decided to buy a microscope, we knew that we would have to modify it. This modification would have to be reversible and non-destructive so that the instrument could easily be returned to its original condition. For a start, we decided that we would try using the Nikon microscope lenses that we had been using for extreme macro photography. As these lenses are of finite design, no secondary (tube) lens is required to form an image in a camera. We removed the upper part of the microscope and replaced it with a home-built twopart tube. This tube has a round dovetail on one end to fit the microscope and a Canon camera adapter on the other.

Our previous experience with manually changing focus for stacked images taught us that we needed to use Stackshot for this purpose. We decided to use a stepper motor sold by Cognysis that can be plugged into and use their control unit. The question then was how to fit it to the fine-focus control on the microscope. We wanted to avoid putting any side strain on the control and did not want to damage the control knob in any way. We finally settled on driving a home-built spindle via a miniature timing belt and pulley system. At one end of the spindle shaft there is a tapered, hollow cup that matches the control knob. The cup is lined with a soft material that grips the knob with only light pressure. The pulley system allows for altering the gearing between the stepper motor and the focus control but we have not needed to change from 1:1. We have slowed the speed at which Stackshot operates to roughly match the speed at which one would turn the knob manually. All the components for the stacking system have been bolted down to an aluminium and wood base plate rather than to the body of the microscope. The tapered sides of the microscope made it easy to hold it down to the base plate with some home-built padded fittings.

For most of the subjects we photograph, the bright field illumination given by simply lighting the subject from below gives a rather 'washed out' effect. Our microscope has a swinging filter holder in which we can place a patch stop for dark field microscopy. The stop only allows light rays that have been intercepted by the specimen to reach the sensor,giving the dark background that we prefer.

Although we are using some of the same lenses on our microscope as we have for extreme macro with bellows, the technique and results are rather different. Whereas we use reflected lighting from above for our bellows system, our microscope provides lighting from below via an optical system. Positioning a specimen on our vertical stand is done by sliding the supporting tube about by hand but we have the much more accurate adjustable specimen holder on our microscope. One advantage of the bellows system is that adjustments can be made to the magnification by shortening the bellows length if a specimen is just too large to fit the camera sensor. In contrast, our microscope has a fixed tube which allows no adjustment in length. One way to overcome this shortcoming is to take two photographs and join them when editing. Doubling up on the number of stacked images is not a particularly attractive proposition but may be worth it if the image is good enough. An advantage of joining multiple photographs rather than taking a single stack at lower magnification is that more detail can be captured.

When high-magnification lenses are used, the distance between the front element and the specimen can be so close that lighting from above is not practical. We have a 40x Nikon lens that we could not use on our bellows system due to the problems with lighting the specimen. There was also a problem with resolving the steps necessary for the short depth of field of this lens. When using our microscope, however, both problems are solved due to the lighting coming from below, and the resolution of the fine-focus control.

One of the condensers for our microscope has sideways movement which allows for oblique illumination. Lighting a subject in this way can increase the amount of detail captured and gives a different effect compared to using a 'centred' condenser.

After setting up our microscope, we looked around for subjects to photograph and decided that crystalline compounds might be worth a try. As we made the replacement tube in two parts, it was easy to place a polarising filter between the microscope objective and the camera sensor. We sited another polarising filter in the light path below the condenser and turned it until the transmitted light reached its minimum. 'Crossing' the filters in this way can produce stunning colours when birefringent crystals are placed between them. All our crystal photographs in this article were taken using polarising filters.

Our method of setting up crystals for a microscope is simply to place a solution of a particular compound on a slide and wait for the liquid to evaporate. The way the substance crystallises is controlled by factors including the concentration of the solution, the ambient temperature and the depth, and size of the drop placed on the slide. The fact that we have not yet worked out the exact interplay of these factors (and probably never will) means that every slide may hold pleasant surprises or be instantly discarded. On the plus side, setting up a slide containing crystals is easy and the slide can be reused after a quick wash. When applying a solution to a microscope slide, we use a pipette for large amounts and a toothpick for small blobs.

The ease with which crystals can be photographed, and the visually stunning results have distracted us somewhat from our usual choice of natural history subjects. The variables involved when setting up and using a microscope for photography have also limited the number of high-quality images of invertebrates we have so far produced. As usual with experimenting, only a small percentage of tests result in a 'keeper' image. So far, we have found that organisms such as rotifers and voticella that require high magnification are better captured with video than still photography because their movement is so important. We have uploaded a sample video, some of which was captured using a microscope with a trinocular head, to YouTube at: https://youtu.be/zdkU3T2Yv6Q

We recently became aware of the technique of adding a waveplate (retarder) to polarising filters when photographing crystals or invertebrates. We have only tried this technique a couple of times but it appears promising enough for us to explore it further in the future.

I would suggest that anyone wishing to find out about what microscopy can offer should look up The Quekett Microscopical Club at: http://www.quekett.org/ We attended one of their meetings recently and were overwhelmed by the friendliness of the members. They had microscopes set up in a hall, and we went out and collected specimens from the local canal. Although we can identify some of the relatively large freshwater invertebrates such as daphnia, we did not have a clue what most of the organisms seen under high magnification were. To find out, we sat with one of the members while he scanned across a small drop of water and identified most of the organisms for us. Even for people not intending to take up microscopy, I think that seeing the amount and variety of life in a drop of water may be worthwhile.



Updated 27/04/2026 16:44:22 Last Modified: Monday, 27 April 2026