Extension Tubes for Macro Photography

We try out some Extension Tubes for Macro Photography with a Pentax K-7.

Posted: 09/09/2011 - 15:23

Extension tubes let you use your current lenses, and alter the focal range so that you can focus on a subject much closer than you normally would be able to. This can give you great macro shots, but also noticeably decreases the depth of field.

These tubes are old manual Jessops extension tubes, so aperture, focus etc are all manual, but you can spend more money and get auto extension tubes, then the camera will control the lens used. I used these with the standard Pentax DA 18-55mm f/3.5-5.6 kit lens, with the lens set to full zoom, and the manual focus ring set to the closest distance. With brighter lenses, you would be able to get more light into the camera, however the narrower depth of field may make sharp shots more difficult.

The extension tubes I used fit all Pentax K mount cameras, and are available for as little as £8 online from Amazon or Ebay. The extension tubes have no optical components, and simply fit in between the camera and your standard (or preferred) lens. They also cause a loss of light, so exposure needs to be longer, and a tripod or higher ISO speed is advisable if you are not shooting in bright sunlight.


55mm lens only, ISO100, 1/160, f/7.1	13mm extension tube, ISO100, 1/250

21mm, ISO100, 1/200	31mm, ISO100, 1/125

13+21 (34mm), ISO100, 1/125	21+31mm (52mm), ISO100, 1/200

13+21+31 (65mm), ISO100, 1/125

Once you've decided what amount of magnification you want, based on how many extension tubes you are going to use at the same time, you can then start shooting something more interesting that a watch! Such as flowers, bugs, and other creatures, although keeping the subject in focus can be tricky if they are moving. The effect can be quite dream-like, with lots of bokeh. The extension tubes may not deliver the sharpest photos, but offer an extremely cheap way to get closer macro shots.