What is a macro lens and how do you recognise one?

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Is your camera a macro lens if it has macro written on it?

Just because your camera lens has macro written on it, doesn't mean it is actually macro. Unfortunately manufacturers sometimes add this word to their lenses as a marketing ploy. Yes, it is true they can focus closer than an ordinary lens. However, don't expect them to get as close as a true macro.


macro dragonfly

Blue Dragonfly

Camera: Canon EOS 400D / Rebel XTi
Lens: Canon EF 100mm f/2.8 Macro
Exposure Program: Shutter priority
Exposure: 0.003 sec (1/400)
Aperture: f/3.2
Focal Length: 100 mm
ISO Speed: 200

Why this image works

This macro shot worked well in bringing out a comical side to the dragonfly. This helped to create a lot of interest in photo sharing sites like Flickr.



How to recognise a real macro lens

A real macro lens has the capability of achieving in the least a 1:1 magnification. This should be written either on the lens or in the manual under specifications. Note: the aperture f stop is not the ratio we are talking about here. For example, the macro lens used to photograph the dragonfly above has an aperture of f2.8. However it also has a 1:1 magnification rating, making it a true macro lens.

Technically, this ratio is a measure of how large the subject appears on your camera's sensor. A lens with a magnification of 1:1 means the subject appears as life size on the sensor. A macro lens with a 2:1 ratio captures subjects twice as large as they appear in real life. On the other hand for a 1:2 lens, the subject appears on the sensor as half its actual size. Therefore a 1:2 lens is not considered a real macro lens.

  • 1:1 or 2:1 ratio is a real macro lens
  • 1:2 is not a real macro lens




example of macro insect

Orange Dragonfly
(click the image to see a larger version)

Camera: Canon EOS 400D / Rebel XTi
Lens: Canon EF 100mm f/2.8 Macro
Exposure Program: Shutter priority
Exposure: 0.002 sec (1/500)
Aperture: f/5.6
Focal Length: 100 mm
ISO Speed: 200

Why this image works

Photographing the dragonfly side on allowed me to achieve full focus in the body from head to tail. Macro lenses have a shallow depth of field. This usually makes it hard to have an insect fully focused. For example, if I had taken this photograph head on and focussed on it's eyes, any body part closer or further away from the eyes, would have been out of focus and blurred. Just as it's wings are in this particular image.



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