Custom macrophotography stand
I do mostly small-subject photography, which includes the magnification ranges of close-up photography, macrophotography and photomacrography, in a studio/laboratory setting. For this reason, over the years I used several types of commercial table-top stands, as well as my own custom-built stands and, for photomacrography, modified microscope stands and commercial photomacroscopes.
For photomacrography at magnifications above roughly 2x-3x, good commercial photomacroscopes and custom-modified microscope equipment are unbeatable. For close-up photography at 0.3x and below, high-end commercial repro stands are often suitable (although all of the medium- and low-end stands that I tried turned out to be inadequate). In both types of equipment, the camera lens points vertically down toward the subject. For close-up shooting with the lens axis horizontal or oblique, a focusing rack mounted on a very stiff tripod and head, or an optical bench, are satisfactory.
The magnification range between 0.3x and 3x, on the other hand, is too demanding for most ordinary repro stands or tripods, and too low for most photomacroscopes. This magnification range requires a third category of fixtures, which for brevity I will call here macrophotography stand, although it covers parts of the magnification ranges of close-up photography and photomacrography. This magnification range also happens to be the one I use most frequently. At these magnifications, it is common to use either a vertical or a horizontal camera orientation (or, more precisely, orientation of the lens axis), and to position the subject as needed. It is far less common (and not especially useful) to use an oblique camera setup, except for product photography and field work on subjects that must not be disturbed.
Some photographers swear by horizontal setups, while others (including myself) find it more natural to work with vertical setups. Since my subjects typically are small isolated objects (often shells and fossil specimens), a vertical setup allows for an easy placement of the subject on or above a suitable background. Most often, I use as background a Styrofoam board covered by black velvet, into which, whenever necessary, I can drive sewing pins to hold the subject at the desired position and orientation. The pins are often completely hidden under the subject (or can otherwise be painted out in post-processing). A black background reduces the risk of flare and undesirable reflections, and matches the typical background I use for mounting individual photographs onto composite illustrations for publishing. A vertical setup also makes it easy to place reflectors and diffusers around the subject by placing them on the same background as the subject. A horizontal camera setup would make all this work much more complex or simply impossible. Finally, a vertical setup usually saves desk space, and articulated screens or right-angle viewfinders make it easy to use a camera even when mounted high up on a vertical column. Therefore, I see no reason to use anything but a vertical setup, and all my custom equipment is built accordingly.
A couple of years ago, I decided to build a stand specifically for the 0.3x-3x magnification range. It was not my first custom-built stand (nor my second or even third), but I am particularly satisfied with the results. The requirements were a high immunity to vibration and sagging (to use continuous lighting and relatively long exposures), a high focusing precision and a relatively high range of adjustable camera height above the subject (a total travel of at least 50 cm). The last two requirements conflict with each other. There are, of course, highly precise focusing racks, as well as less precise focusing mechanisms with a very long travel (there are even worm-screw actuated focusers that are both very precise and very long, but too slow to operate). In general, high length, high precision and quick operation don't go well together in a single focusing rack. It became obvious that I needed two different mechanisms to regulate camera height - one precise and the other quick and providing a long travel.
A common approach to this problem is to provide a long travel with some sort of free-sliding, lockable platform on a rail (which provides the fastest way to change height), and to attach a precision focusing rack, capable of a limited amount of travel, onto this platform. It is also possible to mount a specimen stage (rather than the camera) on the precision focuser, as done in the Leitz Aristophot III and Nikon Multiphot stands). This does make sense for some applications like transmitted illumination, but a moving specimen stage makes it problematic to keep an incident illumination constant while refocusing.
My macrophotography stand grew and evolved over time, rather than being designed in its entirety and then built. In particular, at one point I was able to acquire the focusing mechanism for a Leica stereomicroscope, which is unusual in a few respects: it provides both coarse and fine focusing along a considerable travel distance (12 cm), a smooth operation and a swivel joint to use the focuser either in a vertical or inclined orientation. Its fine focusing is sufficiently precise for the required magnification range (albeit not for higher magnifications and stacking). Typical fine focusers for compound microscopes provide an excessively slow operation at the magnifications of interest. This focuser became the centerpiece of my rack, and proved simply too good to give up during subsequent modifications. It must be mounted onto a cylindrical column, and for this reason it must be attached directly to the stand column. Thus, the mechanism providing a coarse long travel has to be attached to the focuser, rather than to the column. This is the opposite of the traditional approach discussed above, but nonetheless works well in practice. Since the focuser is designed to carry a rather heavy microscope body, it is sturdy and durable enough to carry a camera and a normally heavy rail and bellows system.
Atypically for a high-quality focuser (but unfortunately common in modern equipment), the geared rack is made of plastic. This could make it vulnerable to mechanical damage and wear, but in this case Leica solved the problem by distributing the mechanical stresses over a rack width of 18 mm, and by using a helical gear. In this way, the load is distrubuted across multiple gear teeth simultaneously engaging the rack.
Toward the end of the 20th century, several microscope and camera firms tried to lower the costs of precision mechanical parts by replacing machined metal parts with injection-molded plastic ones, with varying (but rarely excellent) results. For instance, a series of Zeiss stereomicroscopes of this period are generally known among users as the "Fisher-Price scopes" for their garish colors, plasticky construction and toy-like feel. This Leica focuser is perhaps one of the least-bad results of similar "modernization" efforts.
White plastic parts (including focusing knobs) of Leica equipment initially made in this period are known for yellowing/browning and becoming brittle as a result of prolonged exposure to daylight, but subsequent equipment seems to be improved in this respect. My focuser was apparently never used and came in its original packing, and so far has shown no tendence to yellow or craze.
The coarse height adjustment is provided by a 30 cm double-sided Arca-compatible plate, with matching clamps, discussed in detail here. Its total travel range is approximately 55 cm, and its metal-against-metal joints are very stiff. Together with the focusing rack, it provides a total travel of the camera of 72 cm (and an additional 20 cm by turning the focuser upside down with its swiveling joint).
The swiveling joint is a weak point in the current configuration of the stand. An extreme amount of force must be used to lock it steady, and the focuser must be carefully oriented vertically (with a precise bubble level) while locking the joint. However, since I am not using this joint, it is not bothering me enough to do something about it (like replacing the joint with a fixed aluminium bracket, or locking it by drilling a through-hole for a removable locking pin).
The base of the stand is a rather coarsely cut and not polished granite slab (40 x 40 x 3 cm) of the type used for patio floors and garden walks. The ideal linear size of this base is somewhere between 40 cm and 50 cm and the weight between 15 and 25 kg, which provides a stable surface and a sufficient weight, without making it too difficult for a single person to move the stand. Sharp edges were filed away with an angle grinder. The stone is probably imported from China and is not a high-quality granite, but it is cheap and good enough to do the job. High-quality granite used for kitchen countertops and laboratory benches would be even better. A reinforced concrete slab might be an adequate replacement, although natural stone seems to be stiffer and less likely to resonate. Four 5 cm Sorbothane hemispheres at the bottom of the slab, together with the mass of the stone, effectively dampen vibrations of the stand and isolate the stand from minor vibrations of the floor and table. I normally leave the top of the slab covered with a 2 mm thick rubber foam mat (a fine-grained, closed-cell, rather heavy and stiff type). A stiff, solid rubber mat would also be fine. The mat protects the slab and equipment against accidental impacts, and doubles as a light absorber. For this reason, it is useful to choose a dark gray or black, opaque material.
The column is a 25 mm solid steel rod, attached to the base by a through-hole steel bolt. The rod and granite plate form a very stiff joint. The focuser mounts atop the rod. The swivel joint that connects the rod and focuser was originally meant to double the travel range of the focuser, by orienting the latter straight downward or straight upward. This works better in theory than in practice, because it leaves a few centimeters of unusable travel right at the middle of the range, where it is most likely to be needed. However, the Arca slider mounted on the focuser solves this problem and provides a sufficient travel by itself, and I never use the swivel joint.
This macrophotography stand works best with moderately heavy equipment, like a DSLR or Micro 4/3 camera. Heavier equipment, or work at higher magnification than about 3x, is better carried out on a modified microscope stand. A repro stand is better for work with subjects larger than about 20 cm.
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