Tuatara: Volume 7, Issue 2, December 1958
Close-up Photography of Small Plants and Animals
Close-up Photography of Small Plants and Animals
In this article no attempt is made to cover all features of close-up photography; instead, emphasis is placed on some of its lesser known but equally important aspects. Only the 35 mm. camera is considered, and attention is paid mainly to colour photography. The equipment required is simple vet must be reliable, and as much of it will have to be constructed in the laboratory, one should remember that good workmanship will bring its own reward.
For convenience the items of equipment listed below are considered under two main headings, but it must be realised that a certain amount of overlap is inevitable.
In the Field
(1) The Camera
As with all equipment for use in the field, the camera must have lightness and rigidity. The 35 mm. is a good answer to both of these. It must also have an efficient focussing device complete with either a reflex mirror or a rangefinder.
(2) The Lens
Essential requirements are good resolving power and definition, with a focal length not too short. It is a distinct advantage, particularly with small animals such as insects, etc., to be able to photograph them from a distance, thus avoiding any undue disturbance of the subject. Also, a short-focus lens tends to give distortion at close range, as well as allowing too little space for manoeuvring between lens and subject.
The Makro Kilar lens, which will fit several cameras, is a good example, and. although it is inclined to be a little too short in the focal length, has proved very useful indeed for quick work and easy manipulation. Its chief attributes are an incorporated extension tube mounted on a helical device, and an exposure factor scale which immediately indicates the amount of increase in exposure due to increased lens-to-film distance when working close up. The increase in exposure is necessary because a law similar to the Law of the Inverse Square applies as well to lens-to-film distance as to light-to-subject distance. Thus when a camera is racked out to twice the focal length of the lens, the exposure will need to be exactly X4 normal, and so X4 focal length necessitates X16 exposure. The Makro Kilar lens covers a whole range of distances from infinity down to 2 inches.
The purpose of a supplementary lens is to decrease the focal length of the camera lens and so, with the same lens extension, enable one to focus on nearer objects. This is necessary on cameras which do not allow the use of focussing bellows or extension tubes. Under such conditions difficulties in focussing immediately arise, but in cameras such as the ‘Paxette’ these are taken care of by the use of corresponding prisms attached to the rangefinder, thus coupling the rangefinder down to the necessary short focussing distance.
An additional advantage in the use of supplementary lenses is that when used in conjunction with focussing bellows or extension tubes, the lens-to-film distance is reduced and more rapid exposures are possible. Unfortunately, in every case definition of the image is impaired.
(4) The Tripod
This must be rigid, even though for field work it be of light construction. Unfortunately, most light tripods are useless. Either a pan. and tilt head or a universal joint is a virtual necessity. Many good pictures are taken with the camera held in the hand, but too many have been ruined by the ‘slightly blurred’ image.
Steadying the camera by means of a foot strap, the use of a ‘unipod’ or a pistol grip (Fig. 4) are all reasonably good substitutes. Generally with the use of an electronic flash the need for mechanical support becomes less, although in such cases I often use a pistol grip.
(5) The Flash
Electronic flash. Advantages— high speed and low running cost. Disadvantages— high initial cost and additional weight; also there is a tendency for batteries to deteriorate when not in use.
Flash gun. Advantage— low initial cost and greater output of light. In working at close range, the latter is of doubtful advantage without a tripod. Disadvantage— high running cost. If the choice is electronic flash, it must have a flash duration of not less than 1/500 sec. in order to eliminate camera shake. Ring flash overcomes the tendency towards uneven distribution of lighting, but unfortunately produces extremely flat, uninteresting results.
(6) The Exposure Meter
Choose a good one— it pays.
For black and white— standard filters, and polarising. For colour— conversion filters, ultra violet and polarising.
In colour work I have had excellent results from the use of Lifa filters, in conjunction with a Lifa colour temperature meter. With this combination it is possible to adjust any discrepancy between the colour temperature of the light source and that for which the colour film is balanced. The pale page 64 pink CR 1.5, of this series, is particularly useful when used with electronic flash (not already fitted with a ‘built-in’ filter) and daylight colour film. Also, by use of colour conversion filters it is possible to use artificial light colour film in daylight and vice versa.
The first to come to mind is a wire frame (Fig. 1), fitted to the front of the camera at a predetermined distance, constructed to enable the photographer to place it over the subject (e.g. an insect) and release the shutter in a minimum of time. The subject should be in the centre of the rectangle, the perimeter of which represents the format of the image on the film. Provided the lens has been set for a certain distance, the subject will automatically be in focus.
The wisdom of using a pistol grip (Fig. 4) is sometimes debated, but I have experimented with various types and feel the advantages outweigh any disadvantages. The unit should be well balanced. It may be argued that a camera cannot be held sufficiently steady in this way, but it is equally true that it does allow more freedom of action, particularly if the cable release be incorporated in the hand portion of the grip, so that one may release the shutter with the same hand as the one that supports the camera. As I use an Exakta Varex fitted with a prismatic viewfinder for this type of work, I find this arrangement very effective.
If the flash be attached to the camera, the additional weight must be countered by shifting the position of the grip accordingly.
It will not always be possible, or even desirable, to include a scale in photographs, but a number of things may be resorted to, e.g. coins, matchboxes, etc., but for complete accuracy there is no substitute for a reliable scale. Good suitable scales do not appear to be very easily obtained, and it may necessitate making one. This is conveniently done by drawing a large original and reducing it down to the actual measurement by copying.
For measuring flash-to-subject distances the difficulty of using a ruler in a confined space is obviated by the use of two simple measuring devices.page break
Fig. 1: A, base to which frame is attached; B, frame; C, insect. Fig. 2: A, sheet of glass or perspex; B, small glass tank; C, fish. Fig. 3: A, main light; B, secondary light; C, fish; D, ‘cage’; E, glass tank; F, floor of tank; G, camera. Fig. 4: A, camera; B, cable release; C, extension tube; D, electronic flash; E, pistol grip platform; F, pistol grip; G, cable release plunger; H, lens; fl-s, flash-to-subject distance; l-f, lens-to-film distance; l-s, lens-to-subject distance. Fig. 5: A, camera; B, focussing bellows; C, lens; D, secondary lamp; E, mirror; F, main lamp; G, column; H, flower; I, base board. Fig. 6: A, base for ensuring measuring device is at right angles to flash tube (applicable only to types presenting a virtual flat surface to the subject); B, tube; C, threaded collar for securing rod in position; D, rod.
Each consists of a small diameter brass rod fitting neatly inside a brass tube of approximately the same length (Fig. 6), extendable in the first to a total distance of about 9 in., and in the second to about 18 in. These are suitable for extreme close-ups only, as for greater distances than about 18 in. this principle becomes unwieldy, and secondly the need for such extreme accuracy in measuring distances for exposure is not so great.
For lens-to-subject distances shorter than X8 focal length, exposure must be increased as follows: —
(Lens - film distance/Focal length of lens)2
Numerous scales for determining the increase in exposure due to the extension of the lens beyond its focal length have been published; but to pursue this to its logical conclusion, this vital information, relevant to the lens in use. should be transferred on to a detachable scale accompanying the camera. The exposure factor may then be read off in an instant as follows. One end of the scale will be in line with the film plane, while towards the other end will be figures representing the different positions of the lens, coinciding with the number of times exposure due to increase in extension beyond the focal length. This arrangement will be helpful, more especially when using bellows, than with tubes, as in any case each tube or combination of tubes is readily identified with an exposure factor normally supplied by the manufacturer.
A word on exposure charts (Fig. 7). Having ascertained the flash factor for a certain type of film, it is a simple matter to plot the curve on a graph. Any combination of distance and f number may be read off instantly. In Fig. 7 the film is Kodachrome daylight which is found by experiment to have a flash factor of 20 when used with a Mecablitz 36 electronic flash. In actual figures this means, say, at a flash-to-subject distance of 4 ft. the required lens aperture will be f5. By dividing any desired aperture into the flash factor of 20, we automatically have the required flash-to-subject distance in feet. Conversely, by dividing any desired flash-to-subject distance in feet into the flash factor of 20 we automatically have the required aperture. The graph can now be plotted for all combinations of distances and aperture either way. It is pointed out that the exposure can be varied by changing the aperture or the flash-to-subject distance.
(Upper) Stone crab (Lithodes sp.) from deep water, Cook Strait. Length 11/4 in. (Lower) Carrion flower (Stapelia variegata). Native of South Africa.
We wish to use, say, a Makro Kilar 40 mm. lens at f22 to secure maximum depth of focus. With the flash at 48 in. from the subject, the correct aperture would be f5. Therefore, to compensate for the reduction of aperture to f22, this means moving the flash in to 10½ in. (see scale). This introduces at least two more factors: —
|(1)||It will be necessary to increase the exposure for extension of the lens beyond its focal length.|
|(2)||Also an additional increase of up to almost one stop, which my current experience has shown me to be necessary when working at very close distances.|
In the case of (1), extending the lens decreases the exposure by one stop; in other words, to an equivalent aperture of f32 (shown on scale as f32). As we do not wish to alter the aperture from f22, the increase in exposure is gained by shortening the flash-to-subject distance. As can be seen from the graph, the flash-to-subject distance for an aperture of f32 is 7 in., so the flash is brought in to that distance.
In the Laboratory
With some exceptions, laboratory equipment is basically the same as that used in the field.
Here we can exclude daylight. In most cases it will probably be more convenient to use Tungsten lighting. Photofloods for black and white are optional, but for artificial-light colour film there will be no choice. Possible danger of overheating the subject, by the use of photofloods, may be eliminated by using a voltage reducer for preliminary work such as focussing. A highly expensive, yet highly desirable piece of equipment for use with colour is a constant voltage transformer. This prevents ‘surge’, which upsets not only the exposure but the colour temperature as well.
(2) The Column and Base Board Camera Mount (Fig. 5)
The most satisfactory method of holding the camera firmly is by means of a vertical column mounted on a base board which can be swung into the horizontal position when necessary, depending on whether the subject is to be photographed from top or side. It should be constructed of rigid, heavy, but not necessarily bulky material, and mounted on a solid firm base. Vibration must be prevented at all costs, even to the extent of checking on the building itself.
In order to illustrate the functions of as many as possible of the items mentioned above, we will assume we are photographing two small but otherwise dissimilar subjects: —
|(a)||an insect (field)|
|(b)||a small flower (laboratory)|
Our camera for both assignments is a 35 mm. reflex, and in the first case is coupled to an electronic flash rated at 120 joules, and with a flash duration of 1/750 sec. To avoid uneven lighting, the flash is kept as closely as possible in line with the axis of the lens.
The lens is a medium-long focus 75 mm. fitted to the camera body by means of extension tubes. The whole unit is now fitted to a pistol grip.
There will be no time to do any calculations while tracking our quarry, so we must anticipate the conditions under which we will be working. Focus on a small stationary object, approximately the size of an average-sized insect, and with the help of the chart mentioned earlier measure the flash-to-subject distance on the scale constructed for this purpose. Provided nothing is altered between that moment and the moment of actual exposure, there should be little to worry about. Once the insect is in focus, the flash will automatically be at the correct distance.
The makers of more recent models of electronic flash claim they are corrected for use with colour, otherwise it will be necessary to use a pale pink correction filter such as the Lifa CR 1.5 mentioned earlier.
If our work is to be of consistently high quality, as much of it as possible should be done in the laboratory. Our problems, though many, will be more easily dealt with.
We are photographing a small flower, for which purpose we use our column and base board camera mount. The camera is loaded with colour film, and the subject this time is placed on a suitable background of a colour page 69 of our own choosing. Good taste should guide us in our choice. There will be no hard and fast rule, but where possible a background should consist of either a cool colour or a neutral colour. It should ‘recede’ and not ‘advance’— it should enhance but not dominate. A little experimenting will always help.
A useful base on which to rest the subject and background is a focussing stage capable of controlled movement from left to right, forwards and backwards, up and down, clockwise and anti-clockwise, and tilt.
Lighting will consist of two photofloods, one as a ‘main light’ and the other as a ‘fill in’, but as we are using colour film there should not be too great a difference between their respective distances away from the subject.
A small mirror (Fig. 5), or series of mirrors, can be very helpful in reflecting light back into the odd troublesome shadows.
Fancy or bizarre effects, as contrasted to the artistic, should be avoided, but that is no reason for keeping the lighting dull and uninteresting.
Colour film has much less latitude than has black and white, but just the same it should be possible to infuse a charm and sparkle into our transparencies that will make them into something more than just mere coloured records.
Exposures will be fairly long, and in addition to any previously mentioned rules for increase in exposure, we must also allow for the phenomenon known as ‘reciprocity failure’. In black and white, owing to the exposure latitude, its effect can virtually be ignored, but in colour it is something to be recokned with. Briefly, all films are balanced to give maximum efficiency at a certain shutter speed, and any increase or decrease in that speed will produce a decrease in effective film speed.
|Indicated Exposure Secs.||Corrected Exposure Secs.||Percentage Increase|
|1/30 to ½)||No correction|
Wallis and Beatt, 1953. Reciprocity Failure. The British Journal Photographic Almanac, 170-172.
Photography of Fish in Aquariapage 70
Exposures must be brief, and although we are not bound to use electronic flash, it does have at least two advantages— speed and convenience. No vast amount of paraphernalia is necessary, but to ensure the subject is kept easily in focus, and prevented from wandering out of the picture, a ‘cage’ (Fig. 3) of some sort may be used. This should be gently lowered into the water and held firmly (with the subject inside) against one side of the tank. It is advisable to use either glass or perspex fashioned into a box, and leave one of its longer vertical sides open. If the cage is lowered so that the top of it is not lower than the level of the water, no ‘lid’ will be necessary. Conversely, if the ‘cage’ is to rest on the floor of the tank, no bottom will be needed. The photographer, if he chooses, may construct a completely new tank (Fig. 2) of a comparable size to the ‘cage’. A suggested variation is to increase the front-to-back distance of the tank over that of the ‘cage’, and insert a piece of perspex or glass slightly shorter than the length of the longest side to restrict the activities of the subject to one plane. The only virtue in this is for easy adjustment to allow for the width of the subject.
Owing to a number of factors, such as the absorption of light by water, obstruction of light by plants, refraction, etc., exposures are probably best obtained by trial and error.
To avoid reflections of light sources, lamps must be at an angle of more than 45°with the axis of the lens of the camera.
Top lighting, although not essential, is preferable to any other as it is conducive to a more natural and pleasing effect.
If photofloods are used, care must be taken not to overheat the water. Also, prolonged working with the same limited volume of water may rapidly deplete the oxygen content.