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Photographing Your Models

Part Two

By Robert Pounds 
 

Robert Pounds is a journalist, director, cinematographer and has written several articles for photo journals. His many interests include model ship photography. Robert presents a detailed examination of this subject, following the introduction to the basics of model photography previously presented on HyperScale. His perspective of model ships does not lessen the relevance of this article to other forms of model photography.

Copyright for this article remains with the author, Robert Pounds. This article is provided for personal information or research only. All other usage, including republication in model club newsletters, etc, requires express approval of the author

 

I n t r o d u c t i o n

 

People who build models - be they in wood, plastic, or for that matter card and paper - sooner or later want to share the results of their labours with friends and fellow modellers. Short of being able to look at the model itself, photographs are, of course, the perfect way to do this. Photographs are also sometimes required by modellers to illustrate articles, construction guides or catalogues.

Yet some modellers find their photo results disappointing. They may not be sure what is wrong, or if they do recognise the fault, are uncertain of how to fix the problem for next time. Like modelmaking, photography requires a certain level of skill to produce good results. And, like modelmaking, these skills can be learned. But some basic instruction is needed if skills are to be developed. This article sets out to looks at some of the factors that need to be considered when photographing, in this case, ship models. The basic principles, however, are common to a wide variety of photographic situations, and I am sure the reader will readily adapt the basic to her or her own purposes.

For nearly 20 years I was a documentary film director/cinematographer and as a sideline wrote technical articles for several photo journals around the world, including some in the US. I trust the article will not be too technical for non-photographers, but at the same time will be of interest to those who have more than a basic knowledge of photography. There is no special magic involved, but it is assumed for the purposes of the later technical examples that the camera being used is a 35mm single lens reflex. It does not matter much if the camera is fully automatic or totally manual in how its exposure settings are achieved, but you will see that in some instances it is better to be able to over-ride the fully auto features. If you are unsure of what your camera can do, dig out the manual.

The article is broken into three parts: light and lighting, films and their characteristics, and the optics of close-ups.

I apologise for referring mostly to Kodak products, but it is theirs that I generally use and am most familiar with. It is also assumed in the section on colour of light that colour photographs or slides are the intended result. If the finished product is to be black and white, then the necessity for correct colour temperature matching of light sources and film is eliminated.



L i g h t   a n d   L i g h t i n g


Light is the basis of all photography, and the quantity and type of light that you send down the front of your camera lens is directly related to the quality of your final image.

Without going into the physics too much, light, as part of the electro-magnetic spectrum, covers a ‘band’. Perhaps you’ll recall a high school science experiment in which a prism was used to split sunlight into a range of colours The explanation was that each of these colours was at a different frequency and thus the rays were bent at slightly different angles by the prism. All of the colours in the spectrum are present in any kind of light, but the proportions depend on the type of light source.

The quality of light is measured by its ‘colour temperature’. Daylight, for example, is rated at 5400 degrees Kelvin. This is the kind of light that would be emitted by a theoretical perfect black body heated to that temperature. ‘Daylight’ colour temperature light, as provided by the sun, is true only for the period between about two hours after sunrise to about two hours before sunset. Film manufacturers such as Kodak will advise that for the most faithful image quality, in respect of colours, photographs using ‘DAYLIGHT BALANCED’ film should be taken during this period. So pictures of Mum, the kids and the dog are best taken then for the most accurate colour. It also partially explains why the colours in some photographs taken in the shade don’t look quite right.

Outside the two hours margin, the colour temperature of daylight is cooler, resulting in a redder light quality. Portraits taken during this time will show a more ruddier complexion to the skin. If accurate colour rendition is required, the light may be measured with a special light meter called, as you might expect, a colour temperature meter. From there calculations can be made to determine the necessary colour compensating filters that are to be put on the front of thelens. Let me say now that we are now in the realm of (usually) the professional scientific photographer where absolutely accurate colour is required under the existing light conditions. Ship modellers, being basically a sensible breed, have enough nous to simply not try to take colour images when the colour temperature of the light is beyond the range for which their the film was designed.

The most common artificial light source for photography is the photoflood lamp.

Photofloods are designed to put out a cooler light than daylight. As you look at it, it is decidedly yellow in character, and for the technically minded it is rated at 3200 degrees Kelvin. If you photograph a model - ship or female - using daylight balanced film under this light, the results will be reds that are very saturated, whites that look yellow and blues that are dull and lifeless. Compared with the same image taken on TUNGSTEN BALANCED film, the latter is infinitely superior.

So the solution is one of two things: somehow convert the light from the
photofloods to daylight; or use tungsten balanced film stock when using photofloods.

The first can be achieved by putting a filter in the front of the camera lens to modify the light reaching the film to the equivalent of daylight or by placing a gel in front of the light source to convert the light reaching the subject to daylight equivalent.

Correction filters to suit most popular camera sizes are readily available, although your camera store may have to order one in. In Kodak’s nomenclature, the filter you need is a 80A. It is blue in colour, and for exposure compensation usually requires an extra 1.5 stops (a factor of x3) to be added. In layman’s terms, the filter will reduce the amount of light reaching the film, so allowance has to be made for it by either using a slower shutter speed or by opening up the aperture a bit more. Cameras that read the exposure through the lens will automatically compensate for it.

An alternative is to put a colour gel in front of the lamp. Professional lighting units such as those made by Lowell have a gel frame into which the filter material can be fitted. However, as long as the filter material is in front of the lamp (and not touching it) the result is the same - light, equal in daylight in colour temperature terms, at the subject. As one might expect, the gel material is also called 80A. I’ve always used the material made by Rosco.

As an aside, most film makers work the other way round. Kodak’s Eastmancolor motion picture film is balanced for tungsten light right from the start. When using it in daylight, we put an orange-looking filter (called an 85B) in front of the lens to convert the light entering it to the equivalent of tungsten colour temperature. A range of other special filters and gels enable the film maker to cope with light from fluorescent tubes, etc. I recall one production where I put large sheets of green gels over a glass wall in an office to convert daylight to fluorescent equivalent, other filters on the tungsten fill lights to do likewise, and then a filter on the camera to convert all that back to tungsten equivalent.

Using tungsten balanced film with tungsten lights is the simplest solution. However, tungsten rated film is not always readily available, and sometimes even then only on special order of a substantial amount.

So, unless you can get gel for the lights, you’ll need to use the blue correction filter with daylight rated film stock to achieve correct colour balance.

There may be some who’ll say ‘what’s the difference: putting filters on the lights or camera- you’re still going to reduce the amount of light available?’

I am a firm believer that the less I put on the front of the lens, the better. The optical quality of gels doesn’t matter very much: but that of filters on the front of the lens does.

Other might say, "But the photo lab can make colour corrections in printing". While it can be done quite successfully, it is at best a ‘rescue’ rather than a planned solution: far better to get the image as close to correct at the start than depending on massive correction in the lab.

Before moving onto light placement, a few quick comments about ‘making do’ with high wattage tungsten filament bulbs that look like photoflood lamps. Some have a mirror back to them and a translucent front surface; others are designed for all-weather use in, say, lamp fittings outdoors. SOME will give a light output similar or very close to properly manufactured photoflood lamps - I’ve used the former quite successfully, but only reliable way to be sure if they will suit your purpose is to try them out. I suspect that for almost all your photography work they will do, but if you require extremely accurate colour rendition, then stay with ‘real’ photofloods.

Getting the light quality right is only part of the issue. It is how the lights are placed that sets the mood of the photograph.

In any lighting equation there are four components: Key light, fill light, back light and background light. Each of these contributes to the final image - even if sometimes one of the components of the equation is ‘nil’ or ‘not present’.

The best way to discuss each of these elements is to set up a hypothetical photo session.


--------------------Background---------------------
X Background light (set up high - but may be on one side)
X Back light


00000 Subject


X Key light
O Camera
X Fill light



In the above set-up, the key light is set about 30 to 45 degrees off the camera to subject axis. This light, as the name implies, is the main light source and should fall on the principal facet of the object being photographed. In portraiture terms, if the model is sitting three-quarters on to the camera, this light falls on the front of the face.

The key light also sets the basic exposure.

Adjust the key light’s position until the main shadows fall where you want (or do not want) them to fall. Something to watch might be the position of the shadow from the foremast in relation to the mainmast or, perhaps, the position and size of the shadows of the deck fittings. Does a shadow fall from a deckhouse onto an area that you particularly want to feature?

The fill light is used to reduce the depth of shadows produced by the key light. If the fill is placed in the same relative position as the key light, but on the opposite side, the result is a very flat light. Unless flat lighting is required for some technical reason, it is far better to have some shadow tone to introduce a sense of texture and depth. Too deep a shadow and the detail on the fill side is lost. Simply move the fill light back and forth until the shadows look about right. Use your camera’s exposure meter to help judge the lighting ratios. Place a Kodak Grey Card (more about this device later) at the subject but facing directly at the camera. Take a reading with only the key light switched on. Move the camera in closer temporarily, if you have to, to get an accurate reading. Now do the same with only the fill light. A two-stop difference will give you a good result. A two-stop difference is a ratio of 4-1 lighting (and fairly natural looking). Photos intended for publication should err on the flatter lighting side rather than the contrasty side, so a one or one and half stop difference may be sufficient.

Both the key and fill should be placed higher than the camera (the key is emulating the sun, remember) although the fill can be a little lower than the key if that helps reduce shadows on items such as overhanging details, eg, the underside of lifeboats on a model.

The background light, as the name implies, lights the background. For ship models, it is probably a good idea to shoot them on a cyclorama. This is a clever-dick name for what is essentially a background that drops down and curves into and becomes the base on which the model stands. It provides a seamless transition from background to foreground. It may be of any colour but white or a very pale grey would be the most suitable. The background light should illuminate only the background, and none of the model. Its intensity should be adjusted so that it provides a balance between the main and fill lights. It is much easier to do than describe: the background light should not be so bright so that it overpowers the other lighting. It
needs not be as high a wattage as, say, the key light. An old roller blind makes a good cyclorama, provided the surface is not glossy. It has the advantage also of being easy to store.

Sometimes, there is no background light, especially when the effect desired is a deep black behind the model and the back light is used to highlight the model.

The back light is one of the most useful lights of all. Used properly, it will put a ‘snap’ in your images that will make people sit up and take notice. Used wrongly it will produce extremely disappointing results because the halo effect it provides becomes too overpowering.

One of the other names by which the back light is known is the ‘rim light’ and I guess that’s as good a description of what you are trying to achieve with it. This light, usually restricted down by folding flaps on the lamp fitting (called ‘barn doors’) or a tubular snoot, aims to put just a hint of light across the back of the most prominent features of the subject. In portraiture, the light is used to gently kiss the back of the top of the head and the shoulders. It has the effect of making the subject stand out from the background. For a model ship, the danger would be to have this light too bright, thus making the rigging seem to glow rather than having the merest hint of light on the top edge of the lines and spars. The back light is placed high, on the opposite side to the key light. Almost certainly you’ll need to limit the coverage of the light with a sheet of card or something similar. You want the light to spill across the back of the model but not be visible at the camera to prevent flare in the camera lens.

Having said all that, my own preference now would be to place a softening filter (called a scrim) in front of the key, fill and (possibly) background lights. This is a translucent material, and looks like tracing paper. Again, the popular professional product is made by Rosco. The scrim takes away the harshness of direct lighting. The same effect can be achieved by bouncing the light from a white painted reflector or umbrella. Soft, gentle lighting should be your aim rather than a hard spotlight effect.

The light set-up I have described is not meant to be definitive, but a basis on which to start and experiment. For example, as a special effect to highlight the detail of some stern carving, you might reduce amount of fill light right back so that there is more contrast between the key and fill, and thus the shadows reveal the fine detail.

One other point comes to mind: if you are shooting colour, don't be tempted to adjust the lights using a dimmer or rheostat. The colour temperature of the light put out by the photolamps will change with the brightness, defeating the whole purpose of the exercise.

Sometimes a very pale yellow gel is used on the backlight to help make the separation of the planes more apparent, this is especially so if you are using a light blue background.

I have not discussed flash at all as I believe that unless you have fairly sophisticated equipment, including bounced flash heads and built-in set-up lights, or have a standard fixed set-up, the results are too unpredictable for producing quality images. In any case flash, for this kind of work, invariably needs some sort of scrim or reflector head to soften the light.


F i l m   C h a r a c t e r i s t i c s


What film stock do I use? Film manufacturers have made huge advances in recent years in what their film materials will do. Older modellers may well remember the original Kodachrome slide film. It had a speed rating of 10 ASA (or ISO, as it is increasingly being called). Now there is a professional grade Kodachrome rated at 200 ISO. Early colour print films were 100 ASA or slower, now 400 ISO is commonly regarded as the norm and recently I have been experimenting with a very wide latitude film that has a nomial rating of 800 ISO.

The ISO (or ASA) rating is a measure of the ‘speed’ of the film. The higher the number, the less light it needs to produce a correctly exposed image.

Choice of film stock should be made on the basis of the proposed end use. While it is now not as critical as it once was, generally photographs intended for reproduction in magazines and journals should be shot on slide film; images intended for enlargement and framing should be taken on negative stock.

Though things may have changed recently, the sharpest film available to the average consumer is Kodachrome rated at 25 ISO. Nothing comes near it for crispness of image. Negative films have undergone rapid advances and in the end there is very little to pick between them. While it is true that a 400 ISO film will exhibit more grain size than, say, one of 100 ISO, in practical terms for enlargements up to 10 inches by 8 inches the differences are likely only to be apparent under critical analysis. I compromise by using a 200 ISO readily available consumer neg film for most of my stuff, but on occasions I use a professional grade negative 400 ISO stock (which costs a lot more than the general consumer product) for things where I need a bit more speed.

One of the problems with closeup photography is that you never seem to have enough light. You are always working, so it seems, at the extremes of your lens aperture, shutter speeds and film latitude. Film latitude is the amount that you can be under or over in your exposure and still produce an acceptable result. Negative films have a wider latitude than slide films. Typically, you could be out by two stops either side of correct exposure with a negative film and still have an acceptable (note - acceptable) result, while much more than 1/2 of a stop either way with slide film and the result will be an over- or under-exposed image. Obviously, the aim is to always have correctly exposed images.

Added to the ship model photographer’s problems is depth of field. Depth of field is the zone of acceptable focus in an image either side of the point of sharp focus. (Do not confuse the term ‘depth of field’ with ‘depth of focus’- they are two different things.) For example, while your lens may be set to be in focus at 10 feet, in fact, at a particular aperture, the zone of acceptable focus - the depth of field - may be from eight feet to fifteen. This zone is not absolute - somthing is not in focus at one point and an inch further on, out of focus. Depth of field is calculated according to some assumptions about the size of the final image, but the scale provided by the manufacturer on the lens barrel is good enough for most purposes. Depth of field is related to aperture: the wider the aperture (the smaller the f/number) the less the depth of field. Thus in an extreme case, in a very tight close-up, with a lens wide open, the depth of field on, say, a binnacle mounting on a model might be less than 1/16 inch in front and behind. Closing down the aperture will give increased depth of field, but the exposure time will have to be lengthened to compensate for less light being allowed through to the film.

In the end, especially when using extension tubes between the camera body and the lens, it may be possible to run out of marked shutter speeds before reaching the minimum aperture.

As some may be aware, camera shutters and apertures work on an interrelation that says, in effect, for the same exposure, if you decrease the aperture, you must increase the shutter speed. Thus, if you have an exposure of, say, 1/125 sec at f/8, for the same exposure at 1/250 sec, you must adjust the aperture to f/5.6. Automatic cameras make this adjustment for you - some camera programs let you decide on whether the fixed element is to be the shutter and thus vary the aperture for you, or vice versa.

But this linear arrangement falls down when very long (and very short, for that matter) exposures are encountered. Once you get down to exposures longer than about one second, the film emulsion no longer acts in the same way. This is called a reciprocity failure effect. Without going into a long technical discussion on this, corrections have to be applied when very long exposures are being used.

For an article for US Professional Photographer magazine, I produced two images of the Sydney Opera House at night. The exposure meter indicated 8 seconds at f/4, but the resulting image was very dark - at least three stops underexposed. The same subject taken at 64 seconds at f/4 on the same film was correctly exposed.

For a rule of thumb, if the exposure should be 2 seconds, use 4; for 4 seconds use 16, and for 8 seconds, use 32. Results will vary according to film stock - not all react the same, so either make tests first or shoot a set of images using different lengths of time. This is called ‘bracketing’ and ensures that among the half dozen or so photos you take at least one will correctly exposed. Note that with colour stocks there may be some shift in colour rendition, and the use of colour compensating filters is recommended by the film maufacturers. Most film manufacturers provide reciprocity failure effect data for their films, though you may have to get this from the technical information section of the relevant head office..

Thus for a closeup on a ship model where deep depth of field was wanted (and so the camera is set for f/16 or f/22, the exposure, depending on the light, might be quite long. I once shot an extreme close up of some diamonds that, because of the limited light that could be used, required an exposure, including allowing for reciprocity failure effect, of more than 15 minutes. Add to that a couple of retakes and a few shots at different exposures to take care of any miscalculations and there went the best part of a morning.

I referred earlier to Kodak’s Grey Card. This is wonderful piece of equipment and, for the serious photographer who has work done by various photo laboratories, it is a boon. The card, about the size of a standard sheet of paper, is coloured grey. It is a very specific grey, reflecting 18 per cent of the light that reaches it. All photographic exposures are calculated on the basis that the average subject has about an 18 per cent reflectance. The grey is also a dead neutral colour and thus any colour shifts that occur because of a mis-match with lighting or processing can be corrected in the printing stages. The way to use the card is to take one photo with the card in the main subject area and then another AT THE SAME EXPOSURE SETTINGS with the card removed. The lab will read the processed frame containing the card through a densitometer and calculate any necessary corrections before it prints the main image. The cards are quite inexpensive and it is well worth while getting into the habit of using them. Publishers often appreciate the grey card image when submitting photos for publication as the film separators can balance their equipment more easily by working from the card. A company called Macbeth also produces a similar card, but it includes standard reference colour patches as well. The Macbeth card or Kodak’s own colour patch cards are also useful for determining the amount and direction of any colour shift caused by mismatches in film and light colour temperature or reciprocity failure effect.


G e t t i n g   I n   C l o s e   -    T h e   O p t i c s


There are several ways photographers can get close to their subjects. Clearly, a purpose designed macro lens is the best solution, but even then there may be times when just a bit more is required. Sometimes a long focal length lens (telephoto) focused right down to its minimum will do, but the compromise is that depth of field may be quite small.

With many standard lenses (45 mm or 50 mm focal length) the minimum focussing distance may not be sufficient to frame as closely as desired. Some sort of supplementary system is required.

Traditionally, this has been achieved by adding an extension bellows or rings between the camera body and the lens. The major draw-back, however, is that exposure times are considerably lengthened because the film has been displaced further back from the lens. Some automatic cameras can make the exposure compensations, but for extreme closeups, it may be necessary to switch across to manual mode to take care of reciprocity failure effects. Bellows and rings, especially for the modern autofocus cameras, can be quite expensive.

Most modellers seem, however, to only require to get in moderately close. A framing area of about three by four inches seems common. Few seem to need to get in so close as to cover just the area of a postage stamp.

From my own experience, it seems that most modellers are after, for example, the broad detail of the fittings on the foredeck, not the screw heads on the winches.

An expensive way to get in closer is to use diopter lenses which screw onto the front of the camera lens, rather like a filter. They require no exposure compensation, and with the taking lens set at a modest aperture (say, two stops down from wide open or smaller) provide good image quality. Of course, you can stop right down to the maxium f number on your lens. Diopter lenses are available in a range of ‘powers’ from 1 to 6. Usually they are sold in a set of three, made up of 1, 2 and 3 diopters. The lenses may be ganged together for increased power, but always put the most powerful (highest number) next to the camera lens. It is not usually recommended to gang more than two diopter lenses together, but by all means try 3, 2 and 1 together and see what kind of result you get. As a guide, No 3 and No 2 diopter lenses used together should allow you to focus down to about 6 inches.

Diopter lenses are not expensive, but like most things, you get the quality you pay for.

Another way to get in close is to obtain a reversing ring to mount the lens backward on the camera body. Try also putting your telephoto lens backwards onto your standard lens. You may have to make up the adapter ring yourself by using two old filter mounts (remove the glass carefully) glued together.

For owners of older cameras whose lenses simply screwed into the camera body and had no electronic or mechanical contacts to make, simply unscrewing the lens a fraction may provide all the extra lens-to-film plane distance needed to get in that little bit closer to the subject.

In summary, however, it is the quality of light and its placement that has the most effect on your images. I would far prefer to work with lower rated lamps that I could control than multi-kilowatt heads whose light beam could start a grass fire at fifty feet. Quantity can be compensated for (such as through corrections for reciprocity failure effect) but quality - light at the right colour temperature for the film stock you are using - coupled with techniques to give adequate depth of field for the task at hand will always produce outstanding images. It it goes without saying that for close-up work a tripod and cable release are virtually essential to keep the camera steady during exposures. There has (unfortunately) been a trend recently to do away with a cable release socket on some cameras. If you are shooting using a slow, timed shutter speed, you can eliminate any shake introduced from your hand touching the camera by triggering theshutter via the self timer mechanism.

Go to Part One of "Photographing Your Models"


Text Copyright  13 June, 1998 by Robert Pounds
Page created on Monday 30 June, 1998
This page last updated on 18 May, 2001

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