Extension tubes? (1 Viewer)

I occasionally see references in posts to "Extension Tubes" and I do not know what they do.I have a 350D + a 400 f5.6 lens and wonder if I could use some and if so how would they help me.And of course are they expensive?

Max.

Hi Max

Extension tubes go between the camera body and the lens, they reduce the minimum focusing distance of the lens. So they can be very useful as they will allow you to photograph things that are closer to you, however you lens will not focus to infinity when they are in place. They are not overly expensive, especially if you buy off brand ones.

here are a couple of threads that may be of help...

http://www.birdforum.net/showthread.php?t=60735

http://www.birdforum.net/showthread.php?t=49354

One further thing is that they come as either manual or autofocus. Manaul tubes are dirt cheap and will work but only with the camera fully on manual - focus and exposure. They are simply hollow tubes with no glass at all so there is no degradation in image quality.

Auto tubes are a little dearer - second hand they can be had for £30-£40 for a full set - but are well worth the money.

I find then most beneficial when used with a 400mm lens as it means macro photos can be taken at greater distances from the subject - ideal for insects - but they work just as well with shorter lenses and for birds.

With 20mm tube on the 400mm f5.6 lens the minimum focus distance is just over 2 mtrs with a max focus distance of around 12 mtrs. I use the Jessop canon af tubes (set of three around £70) with no problems at all.

Thanks for the info. everyone.

Max.