Macro Photography

Bill Hall

Based on a talk given to the society on 16th September 2003

contact : William Hall william.hall@australianpork.com.au

Reference Book: Close-ups in Nature by John Shaw. Published by Amphoto USA

Definition: macro = anything large or on a grand scale, make large. Hence macro-photography is the making of a small subject large within the image format. Generally speaking it is when the image is about 1:2 or 1:1 on the film, i.e. the actual dimension of the subject is half or the same actual size on the film respectively. So an object 5mm wide in reality is actually 5mm wide on the film (1:1). Under field conditions the difficulties of getting photographs in which there is substantial magnification so that our 5mm subject actually measures 10 mm on the film (2X magnification) are usually such that macro-photography is limited to 1:1 (life size with no magnification). Some of the previous comments are not applicable to digital cameras where there is inbuilt magnification of the image.

Equipment:

Tripod: in most or many cases the subject will be close to the ground if the subject is being photographed in the wild so some means of camera stability will be necessary. Most tripods with the exception of the Benbo do not allow ground level operation. The use of a clamp on the leg of the tripod or a beanbag or a table tripod will permit near ground operations. The use of a central pole with the camera mounted upside down is an option also if you are so inclined. As most macro-photography shots require relatively long exposures then the use of a tripod is essential.

Ball head: a great aid in getting the camera into the correct position but not essential, the use of a double clamp, which contains 2 small ball heads, can be used if a ball head is not available. A 4" ball head is not essential as there are smaller cheaper options available from Bogen that work very well.

Focusing rail: for either a pan head or a ball head this an extremely useful piece of equipment that can move the camera over a distance of about 4" (100mm) front to back and about 2" (50mm) side to side without having to move the tripod. It can be used to get accurate focusing.

Extension tubes: without the use of specifically designed macro lens a normal 50mm lens can be made to perform as if it were a 50mm macro lens and achieve 1:1 or 1X magnification by the use of extension tubes. In this situation one needs 50mm of extension. Extension rings can be purchased in sets of three (i.e. each tube is of a different length) but together they give a total length of 50mm. For a 100mm non-macro lens one would need 100mm of extension.

Bellows: these perform the same function as extension tubes but the length of the extension is variable over the range or length of the bellows. The down side of using bellows is that you need a double cable release that will stop down the lens at the same time as the exposure is triggered in the camera body.

Reversing rings: these allow the normal camera lens (50mm) to be reverse mounted on the camera body. They are cheap and very effective and are available for a range of lens diameters.

Diopter lens: these are supplementary lenses that can be screwed into the front of a normal lens to give varying degrees of magnification. Usually classified as 1, 2 or 3, they can be stacked together so that all 3 lenses can be used at the same time. They are available for larger lenses e.g. Nikon 4T and the 6T.

Macro lenses: these are lenses specifically designed for close up work and come in a range of focal lengths from 50mm to 200mm. The advantage of the longer focal length is that the camera to subject distance is increased and the viewing angle is reduced so that less material behind and to the side of the subject is included. The 100mm or 105mm lenses usually are 2.8 or 2.5 aperture and the 200mm lenses are f4. The 200mm lenses may be 1:1 or 1:2 capabilities. After market lenses e.g. Vivitar are of good quality and often cheaper than big brand name lenses.

Long focal length lenses: these lenses (200 or 300mm) can be used in conjunction with extension tubes to achieve some degree of macro capability. However the ability to focus to infinity is lost.

Wide-angle lenses: as with long focal length lenses 28mm lenses can be used with a short extension tube to achieve a macro photo, but the camera to subject distance becomes very short indeed.

Viewfinder focusing screen: there are a number of options available. I use a plain screen with ruled lines. If you are happy with a split image screen and can accurately focus then continue to use it.

Getting the Photo

Now comes the difficult part getting on film what you see. For any successful macro-photography in the field wind conditions have to be calm or very close to calm with periods in which there is no wind. To this end patience is a wonderful virtue. Exposure times will often run to several seconds and are commonly around _-1/2 second depending on the aperture chosen. Hence the use of a tripod is strongly suggested as well as the use of a cable release to trip the shutter.

Exposure can be determined by the camera light meter with the aperture priority mode selected. In this way you control the depth of field. In some situations the use of a hand held light meter might be appropriate or metering off a gray card; but remember to allow for the loss of light that will occur if long extension tubes are being used. In this case bracketing is strongly suggested.

Despite the use of a depth of field preview button it is a good idea to run through the range of focus to look for distractions that may show up as "hot spots" in the final image. Often these spots appear relatively innocuous in the viewfinder but once the film is developed are disasters.

The depth of field chosen as a consequence of the aperture set is one of personal choice, but usually will be in the range of f11-32. This is purely the option of the photographer. However for soft muted backgrounds the wider apertures are desirable unless the background is a long way behind the subject. Remember that as the subject gets smaller and the camera is placed closer to the subject and the settings on the camera approach or are at 1:1 then the shallower is the depth of field. So in these situations the use of a small aperture (f32) is often necessary if the entire subject is to be in focus. This will result in long exposure times; reciprocity failure while talked about is not an issue with modern film or digital cameras!

Lighting is problem in some situations and may result in long exposures even when large apertures are used. The use of a flash is one way around this problem but results in photos that shout, "FLASH" to the viewer. The use of reflectors may help to direct light onto the subject and reduce exposure time. I find that direct sunlight onto most subjects' results in colour that I dislike, so even in sunny conditions I will shade the subject with an umbrella. Large golf umbrellas with alternating white and black panels work very well as well as being useful as wind breaks. Overcast days are ideal for macro-photography as the light is diffused and contrasts are minimized.

I have used Fuji Velvia film for the past years ever since it became available and find it gives me the colour rendition that I think I see in the subjects I photograph. Use the film that makes you happy.

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