Ancient Coins
The discussion that follows is not an expert discussion of coin photography. It is simply an explanation of the techniques used to produce the coin images on this site. The photos were taken over a period of years (at least one image here dates to the 1960's) using a variety of equipment.
My opinions as to what makes a good photograph has changed somewhat over the years and will probably continue to develop as time progresses. I consider many of the images on this site flawed but they are the best I have of the coins shown.
Even more recently I bought a very sophisticated, but still 'amateur' model, digital camera. I have taken some very nice coin photos with it and have reported my experiments with it on my Digital Camera page. I am still of the opinion that I can do better with my 35mm camera but the gap is closing rapidly. The biggest advantage of the digital camera is that one is freed from depending on commercial film processors (the guys who lose your film or turn your silver coins a sickly green). Now you can be free to shoot photos without considering how they will be printed by humans and machines who know nothing about ancient coins. The disclaimers having been stated we will proceed with the remainder of this page covering the use of an 'old fashioned' camera. Prints were then scanned on a flat bed scanner for display on this page.
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The upper image was produced directly on a flat bed scanner. Below is a photograph of the same coin shot on ISO 100 color print film with a 35mm camera and lighted by a cluster of bulbs near the lens. Exposure of about 2 seconds was made at f/11 using the automatic metering system of the camera. Two separate images were scanned from prints, combined, adjusted in density and placed on a black background in the same manner used for the direct scans. |
There is no such thing as the best camera. Over the years I have used Leicas, Hasselblads, Linhofs and most of the other big name cameras (now even a Nikon Digital!) and feel confident to make one statement: Few bad photos are made bad by bad equipment; usually the problem is a bad photographer. The best lenses are only sharp when properly focused; the sturdiest cameras produce fuzzy pictures when held by trembling hands.
For coin photography I recommend any brand (my current camera is a Contax) of 35mm single lens reflex with a built in light meter that reads through the lens (preferably favoring the center of the image or 'center weighted'). The lens must be interchangeable to allow introduction of some sort of spacing device behind the lens to allow the rig to focus close enough to fill the frame with the smallest coin in your collection. This extra 'extension' can be in the form of an expensive adjustable bellows or relatively simple set of extension tubes. Use of either device will be easier if you opt for the 'automatic' models that retain linkage of automatic diaphragm operation of the lens. How many tubes you will need will depend on the focal length of your lens and how small coins you want to shoot.
35mm cameras usually come supplied with a 'normal' lens with a focal length of about 50mm. When a normal set of extension tubes are added to this lens the camera can generally fill the frame with a denarius size coin. To achieve 1:1 ratio reproduction the lens must be 'extended' beyond the normal 'infinity' position a distance equal to the focal length of the lens. Part of this distance can be accomplished by the helical focusing mount of the lens itself but the rest must be provided by the tubes. Lenses of longer than normal focal length will require more forward displacement while 'wide angle' or short focal length will require less. In the same manner the subject to film distance for 1:1 reproduction is a factor of the focal length of the lens. A 28mm lens can be extended easily to fill the frame with a tiny fractional silver coin but the working distance from the coin to the front of the lens might be best measured in millimeters. My personal preference is a lens of greater than 'normal' focal length, perhaps something in the 100 - 200mm range. Working distance at 1:1 will be several inches so there will be less conflict with the camera position and the place you wish to position lights. Over 200mm focal lengths can be used but the distance becomes a problem and most of us would need a ladder to climb to the camera to see a coin placed on the floor.
Special 'macro' lenses have much more travel in their focusing mounts and can allow filling the frame with sestertius size coins with no extra extension but most collectors have smaller coins and will need the tubes. Sometimes the optics on these special 'macro' lenses are optimized for best results at close distances but the difference here may not be apparent unless you are making very large prints of coins that are much sharper than any in my collection. 'Macro' lenses are convenient but often considerably more expensive than the same lens in normal focusing mount. Are they worth it? I own two; but that is just an opinion.
Again in my opinion, there is one thing to avoid in selecting a 'macro' lens. Some adjustable focal length or 'zoom' lenses have a setting for 'macro' focus. This is accomplished by a change in the internal linkage of the lens so the focal length adjustment is translated into close focusing movement. This works only using the shortest focal length of the lens so when the lens is focused on the nearest setting, the subject may be almost touching the front element of the lens. This makes lighting the subject rather difficult due to the shadow of the camera. Another 'cheat' that does not work well are 'diopter' lenses that go in front of the lens to provide close focusing capability. These negative lenses reduce the focal length of the lens and encounter the same problem of short working distance provided by the 'macro-zooms.' At this time, consumer grade digital cameras (under $3000 or so) rely on these non-interchangeable zoom lenses for macro photography. While it certainly is possible to work around the limitations of these lenses, it is, just as certainly, easier to work with interchangable lenses.
There is one 'cheat' that works. The lens 'extender' (also called Tele-extender or Tele-converter) is a device that fits between the camera and the lens that doubles (sometimes 1.4 to 3 times normal) the focal length of any focal length lens. A 50mm becomes 100mm and 100mm becomes 200mm. The extended lens retains the same close focusing distance of the original lens so the same size image is produced at an increased working distance. These 'extenders' have two faults for many photographic uses but neither of these are serious to the coin photographer. First, the 'extended' lens loses some image quality. In particular the resolution at the corners of the frame can be degraded. Fortunately, a photograph of a round coin does not use the corners of the rectangular frame so any loss of quality there goes unnoticed. Second, the intensity of the light passed by a 2X 'extender' is reduced by two full stops. This is a serious problem for someone using an 'extended' telephoto to photograph moving subjects but makes very little difference when the camera is mounted on a solid tripod shooting a motionless coins. The loss of image quality with these devices can be reduced by using smaller f/stops; again an impossibility for stop motion or hand held photography but no problem when shooting coins. Some brands of 'extenders' are better than others so it might be worth spending a little more and buying one of the more expensive (usually having more glass 'elements' in the design) models. Here again part of the requirement for quality of the image is limited by the sharpness and size of the subject. When shooting tiny insects, every little bit of sharpness reveals even more amazing detail. When shooting coins, the available detail is often limited by the subject sharpness more than by the lens quality.
Whatever the camera, one rule is certain. Coin photos should not be taken hand held; a substantial tripod or other stand is an absolute necessity. At least one of you is thinking about those great shots you hand held through the glass display case at some museum but, seriously, can the best of these compare to the shots in the high grade auction catalogs or on the postcards sold by that museum? If you use a tripod, select one that weighs more than you want to carry and allows the center column to be reversed to ease shooting straight down. Lightweight, spindly tripods are a waste of money. If the tripod is not rock solid, vibrations will ruin the photos.
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The Contax 137 camera is mounted on the frame of an old Durst 609 enlarger using a Leitz ball socket. Lights are attached to a wooden frame which allows changing position of the bulbs. The 100mm macro lens (Yashica) is used with a 2x Tele-Extender and extention tubes for closer focus required by small coins. A lens hood fashioned from a tin can (painted black inside) protects the lens from stray light. The subject coin (a sestertius) is supported a distance above the brackground on a dowel rod set into a scrap of wood. |
Better than a tripod is a copy stand made for close up photography. I use a stand made from the baseboard and uprights of an old photo enlarger. These are available at low price from used camera stores; tell them you want an enlarger that does not work but was originally used for large or medium format negatives. Just as with tripods: the operative words are 'Rock Steady.' To adapt my old enlarger frame I had to attach a ball joint camera mount to level the camera but some enlarger frames even have a flat plate perpendicular to the base that would allow direct mounting of the camera with a ¼" 20 thread tripod screw. At a higher price, commercially produced copy stands are available.
Now that we have the camera and have fixed it solidly on some sort of support it is time to consider several topics that separate the good photos from the ordinary.
Several characteristics of light come into play as important subjects in coin photography. We will discuss color balance, direction, light size, distance and number. White light is a mixture of many colors. The eye (and brain) can adjust and accept quite a range of color mixes in nature as 'white.' When photos are produced the variations in light color are fixed on paper but the brain refuses to accept variations from normal as natural. Color films are generally balanced for use outdoors in 'daylight' and give good color results only when the photographer balances the light color to match the film. While it is quite possible to take coin photographs outdoors in daylight, most photographers use artificial illumination. Tungsten light bulbs are considerably more yellow in balance than daylight. Camera stores sell correction filters that will restore a proper color balance. For most combinations of daylight balance film and tungsten lights, an '80A' filter will give satisfactory results. If the goal is color prints rather than slides, final color adjustments will be made in the printing process but the difference between daylight and tungsten is too great to be compensated fully in printing. Slide film is sold with daylight balance which can be used with the 80A filter or tungsten balance which will give good color with no filter. Know which you are buying and make the light match the film you are using. Failure to observe this requirement will cause your gray denarii to photograph as gold.
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Direction of the light is a factor that should not be obvious when looking at the photograph. If the average viewer notices that the light is coming from a certain direction it is likely that the result was unnatural. There is a lot of room for opinions on this subject. If light in the photograph shows direction I usually prefer that it comes from the top. Some workers prefer the light coming from slightly behind the head to produce a narrow shadow on the front of the portrait. Never light a coin from the bottom. The effect is reminiscent of a Halloween ghoul holding a flashlight shining up on the face. There is no best single lighting arrangement for coin photography; every coin is an individual requiring consideration of its relief and surface characteristics. Many photographers, myself certainly included, like the results when the light comes directly from the camera position. The light appears to originate from the lens, shine down on the coin and go straight back up to the lens. This is termed 'axial lighting.' Proper axial lighting is accomplished by fixing a pane of glass or half silvered mirror between the camera and the coin. Light is shined on the mirror where part is reflected onto the coin. Light travels from the coin back to the mirror where part is passed through to the camera. This system loses a lot of light and requires great care to keep the mirror clean. Axial lighting can be approximated by placing the light as near as possible to the camera. If you followed my advice and are using a long focal length lens, the great working distance will result in the angle between the light to be small if not quite the zero degrees provided by proper axial lighting.
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| This is actually an example of 'pseudo-axial' lighting since the illumination came from a bank of lights very close to the lens rather from the exact axis of the lens by means of a beam splitter. Note that each letter of the legend and each device is shadowed on every side. |
Axial lighting has two great advantages in coin photography. There is no better light to bring out coin legends. The light falling on the top of each letter produces a bright letter while the light striking the edges of the letter is reflected off giving a dark edge equally on each side of the letter. If you see a photo with even shadows all the way around letters and other raised devices you can suspect axial lighting was used. The second advantage with axial lighting is in the photography of very high relief coins such as Greek silver. Directional lighting will produce shadows on the surface of the coin that may conceal desirable details but axial light will provide an even image. Disadvantages include a tendency for the direct reflection of the light into the lens to include a blue glare that can throw off the proper color balance of the brightest parts of the image. Similarly, the appearance of colored patina is made less striking while the raised details are emphasized. This can be a real disadvantage when the patina is the most important feature of a coin.
In the discussion of camera supports I recommended use of a copy stand camera support. Many of these stands come equipped with lights fixed at 45 degree angles from each side of the base board. This is great lighting for the photography of flat paper objects but horrible light for three dimensional coins. After considerable experimentation (actually 'playing around') with the subject, I am convinced that the best light number for coin photography is 'one': one big one. A large light source provides soft edged illumination lacking the harshness of smaller lights. Two lights with a considerable space separating them produce conflicting shadows that look unnatural but a single large light merges these shadows into a natural appearing whole.
The ultimate large light source is the open sky. Conversely, the ultimate sharp single point light is the direct sun. When it comes to making natural looking photographs it is hard to beat working outdoors. Consistency of angle and other characteristics are problems as are wind, weather and nosy neighbors. If you decide to work outdoors try to find an area of open shade out of direct sun or work on overcast days.
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This photo of a very small coin was lighted by the open shade of an overcast sky. The lack of direction of this light helps to fill in the high relief details of the globular little coin. A 50mm Leitz enlarging lens was used at f/16 on extention tubes. |
Now a secret of counting: Two or more lights placed near each other photograph rather like one larger light. To simulate the larger light I desire my photo rig used for recent additions to this site used four standard light bulbs with no reflectors. There is a lot of light bouncing around with a general, average direction of the camera position. The lamps were mounted on the top and right sides of the camera (since the photo was taken I have added another lamp on the left as an experiment) close enough to each other that their individual shadows are not separately visible. The top lights are not firmly fixed but attached to a sliding bar that will allow changing the angle to produce variations in lighting from than the 'pseudo-axial' light I usually prefer. Some coins photograph better using only part of the lights; some require the entire set. There is a lot of trial and error in my technique but the 'what you see is what you get' aspect of the single lens reflex camera system allows seeing what can be expected before the picture is taken.
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These two photos were made with the same light bank at the top and the right of the coin. The right image was improved by very slightly tilting the coin so more light would fall on the face. This high relief and unnaturally polished coin would have been better photographed with additional light on the left side to fill in the heavy shadow behind the head. |
This 'preview' feature explains my strong preference for incandescent lights over flash units. It is true that the modern electronic flashes are daylight balanced and very easy to use. My camera even meters the flash output off the surface of the film so good exposures are quite easy. With flash, however, we lose the ability to make a very small change in the angle of the coin and see the results through the lens. Sometimes this little change can make the difference between an ordinary photo and a really special image. This is particularly the case if you are trying to bring out some minute detail (e.g. evidence of an undertype on an overstruck coin) or trying to hide some flaw. Some workers use a ringlight, a flash with a circular tube that encircles the front of the lens and produces shadow free lighting. I have very little experience with these units but was not particularly pleased with my short trial many years ago. Perhaps I should try it again since a ringlight certainly would be a simple rig to carry around for work away from home. The Nikon camera company once (still?) produced a 300mm macro lens called the Medical Nikkor which featured a built in ringlight. It was expensive and I never actually used one.
The minor adjustments to angle of the coin mentioned above are made easier for me by placing the coin on top of a dowel rod with a small piece of (sulfur free, please!) clay on top. The dowel is set perpendicular in a board and the background material (with a central hole) is passed over the dowel and rests on the board. The clay allows tilting of the coin to adjust the degree of glare reflected into the lens. The dowel should be slightly smaller than the coin being photographed to avoid accidentally appearing in the photo. A series of sizes will be needed to photograph all coins. I have them from 1/8" to ½". Dowels supporting larger coins should be longer (about 6" works) to throw the background material out of focus while the smaller diameter ones are made shorter so errors in construction and camera alignment will not result in the support showing in the photo.
All that light bouncing around makes it important to consider that stray light can ruin an image by creating glare when it strikes the front of the lens. Eliminating this stray light is the job of the lens hood. Many cameras come with short lens hoods that are meant for use in general photography. As a lens is moved forward for close photography the length of lens hood needed increases. Too long a hood will cause shadowing of the image corners but the correct length is just short of that length. You may be surprised how long a hood you will be able to use. My current hood is made from a tin can painted flat black inside and held in place by a rubber lens hood that came with some lens I once owned. A tube of black paper can also be used as could anything that will protect the front of the lens from light coming from anywhere other than the subject.
Accurate focusing is critically important in coin photography. When working with such small subjects the depth of field (area in focus) is very shallow. Since the photographs are being taken on a firm support there is no reason not to stop the lens down to increase the depth of field. I usually use f/11 as a setting that provides sufficient depth of field and allows exposures to stay within the range available on the automatic metering on my camera. Many of my exposures are in the one to five second range. Brighter lights could reduce this but would add heat to the coin and camera area for no good reason. There is a trick to focusing close that I highly recommend. Always set the focus on the lens to the setting that will produce the size image you desire and then, using the tripod or copy stand mechanism, move the whole camera/lens assembly as a unit to fine tune the focus. When you move the focusing mount of the lens at very close distances you are not only changing the lens to film distance but also the lens to subject distance. This double variable will cause you to chase the ideal size/focus settings and can be frustrating. Presetting the lens to film distance and working only with the subject to lens distance is much easier.
At some time most of us will desire to produce accurate exact size photographs of coins. To accomplish this I recommend always taking your film to the same place for processing and always ordering the same size prints. Most photofinishers use equipment that is preset for a fixed magnification (if yours does not, change finishers). If you, by trial and error, find the focus setting that gives 1:1 results one time you can return to that setting and expect the same magnification ratio each time when you get back your prints. The setting for my equipment is marked on my lens mount with a tiny scratch and will be good until my favorite processor buys a new printer. Custom labs that use adjustable enlargers are much less likely to provide consistent results in this manner.
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This coin is deep black in color. The print returned from the photo lab was much too light for good appearance and much, much too light for accuracy. In the scanning process I have darkened it a bit but mostly just restored the black background to make a photo that looks better than the coin. The 'axial' lighting gives more a photo of the glare from the coin surface than it does of the surface itself. This is an excellent example of even shadows on the edges of the letters. |
You can help the automatic printing equipment used by most finishers by shooting color negatives that will be easy for the equipment to print. Printer programs assume that the photos are full of average things: neutral colors and middle grays. If you shoot your coins on a bright blue background the equipment will try to correct this excess blue by adding excess yellow to the prints. Bright green coins on a neutral background will confuse the printers into removing some of that excess green producing a washed out gray green rather than an accurate record of the patina. Shooting those green coins on a magenta (red + blue) background might fool the printer into making the green coins greener. Dark coins shot on a black background may be reproduced too light while light coins on a white background will be too dark. Some printers read their balance information mostly from the center of the negative so results on single coins can be improved if the image fills the frame. Shots of more than one coin will be best if the background is neutral gray.
These problems with color are only a factor for color prints made on automatic equipment. Slides can be expected to be proper color as long as you selected the correct film to match the light source (daylight/tungsten) used. While slides are great if you want slides as the finished product, most of us prefer prints for most uses. Prints made from slides are usually not as good as prints from negatives. Since scanners to convert slides to computer files are somewhat more expensive than flatbed (print) scanners, most of us will want to have this done commercially. Color prints made by 'custom' printers can overcome the problems mentioned if the operator understands what you want. A good way of getting good results is to find a lab where you can actually speak to the person who will print your photos. 'One Hour' labs can be excellent if you can find an employee who cares and will work with you to get the proper results. All of the photos scanned on this site were processed by the cheapest grocery store lab in my area. I avoid shooting negative I know they will not handle properly and make minor corrections while scanning. Of course, problems with color balance are eliminated by working in Black & White. Unfortunately, demand for this process is diminishing to the point that it is difficult to get good Black & White processing in some areas. Most of the images shown on this site are in color but I often prefer to work in Black & White. This preference is mostly because the lighting style I find most pleasing (axial) tends to introduce a glare that changes the color rendition of the photo. Since space is a factor on my page, I have opted for smaller monochrome files for my Severan denarii overview pages but use the splashier color images for the more popular sections of the site.
Since the camera will be securely fixed and subjects are not moving there is no reason to buy high speed films. Lower speed films (ISO 100) are sharper, cheaper and better for coin photography in every way. Individual equipment may require that you set your camera on something other than the recommended setting. My combination of lights, camera and techniques give me best results when ISO 100 film is exposed at ISO 64. Your situation may be different. Film choice may soon be a thing of the past as more of us move on to digital cameras. Due to the lack of interchangeable lenses, currently available amateur equipment is not very suitable for very close photography. Professional digital cameras with interchangeable lenses are still very expensive but will eventually be the best answer for the coin photographer.
Until advances in technology make professional digital cameras available at a lower price, most of us will continue to use conventional cameras for coin photography. Single lens reflex cameras that allow focusing on very small objects and show the expected results "through the lens" before the picture is taken are required. Decisions on exact equipment and materials are not as important as learning to use the equipment to its full potential. To accomplish this the photographer will do a lot of "trial and error" work until experience with a wide variety of coins can be gained.
(c) 1997 - 2000 Doug Smith
