Monday, October 5, 2009

Macro Photography – Part 1 Techniques


A fly from my garden

Macro photography is nothing but close up photography that deals with capturing the smaller things around you. You will be amazed at the almost infinite photo ops available in your backyard or garden. Most point and shoot cameras and SLRs have a macro mode. Usually it is represented by the picture of a small flower in your mode dial. Once you engage this mode the camera will try to focus closer to the lens and some cameras will allow as much as 2cm. The exact value will vary and you should check your camera manual to see the details.

A true macro or a 1:1 macro is where the image of the subject formed on the camera sensor/film is the same size as the real life subject. Many general purpose lenses are capable of 1:2 macro which means the image formed on the lens is approximately 50% of the size of actual subject. The lenses will also label the minimum close focusing distance on its body (usually around where the lens cap fits into the lens)


A grasshopper

Techniques to capture Macros:

  • A dedicated macro lens is probably the best option out there for people who are seriously into macro photography. These are expensive but offer very good IQ. These dedicated lenses are usually primes and are very sharp. They also double as a good portrait lens. You can choose one based on the focal length. A 100mm macro lens will give you better working distance than a 50mm lens. This means you can stay farther from spiders and bugs.


  • Extension Tubes or bellows: This is what I use. Its not as easy to use as a dedicated macro lens, and you also loose the ability to focus at infinity (basically means you can only focus at close distances when tubes are mounted). I use my 50mm f 1.8 prime lens with Kenko extension tubes. Extension tubes are simple hollow tubes that provide magnification by increasing the distance between the lens and film/sensor plane. The further the lens is from the film/sensor (i.e by stacking multiple extension tubes), the closer the focusing distance, the greater is the magnification you can get. The thumb rule for getting 1:1 maco is that the you should provide a spacing equal to the focal length of the lens used. For my 50mm lens, i need to stack extension tubes to 50cm to achieve a 1:1 macro. The main problem with using this kind of setup is that the available light reduces by half when using extension tubes (as distance increases, the amount of light captured reduces). This means you will have to deal with longer shutter speeds or high iso. The Image quality is not affected using this technique
  • Using macro screw in lens adapters are also a way to cature macro photos. These typically screw into the lens thread . The problems of using this could be reduced sharpness and image quality. A low quality adapter will also lead to chromatic or optical aberrations in the final image.
  • Telephoto extenders could also double as macro adapters for lenses. But just like Extension tubes, the availability of light reduces when you use them, but the Image quality is not affected if the usual high quality extenders are used.

  • Reverse lens / Reversing Ring is another technique used. This is an inexpensive way wherein you need to purchase a special reverse lens adapter that attaches to the filter thread on the front of a lens and makes it possible to attach the lens in reverse.



Water droplets on a leaf

In the next section of this series we will look into the various issues faced in macro photography as well as some tips on these areas.

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