Kenko Tubes

[ketan]

Hi,
What are Kenko tubes and what are they used for. I was curious to see a photograph of an insect at canon forum taken with 30D + 50mm f/1.8 + Kenko tubes.
Are they worth additing to lens collection?
ketan

 

[JIP]

They are used to let you be able to focus closely to an object. As far as value to you that is a personal decision.

 

[Don Simon]

Hello there. 'Kenko tubes' probably refers to extension tubes (Kenko is just the name of the company). Extension tubes simply increase the distance between the lens and the film or sensor. The result of this is that you can get much, much closer to the subject than would otherwise be possible, and so they can be useful for 'macro' work.

There are a couple of drawbacks to extension tubes though. First, they let in less light, so the maximum aperture of your lens is effectively reduced. Combined with the extra length of extension tubes, this may be quite restrictive on available shutter speeds, with shots requiring either a tripod or a lot of light if you want to shoot handheld. Secondly, you will probably have to manual focus, which may or may not be fine depending on your camera and your eyes. But perhaps the main drawback is that although you can now get much closer to close up subjects, the lens-and-tube combination is only really good for that...whereas a true dedicated macro lens can be used for close-up work and also general photography at all distances. If shooting stationary objects indoors, a bellows may also be better than extension tubes since it is more adjustable.

Having said all that, extension tubes can be a cheap way to get into 'macro' photography and I would definitely recommend them if the price is right... though obviously there are other options, like lens reversal (very cheap), close-up filters (fairly cheap), or saving up for a dedicated macro len (not very cheap at all). As for tubes, I believe Canon and Nikon make their own, but the Kenko ones seem to be fairly well respected, and they have the electrical and mechanical parts necessary for auto exposure (and in theory auto focus) so they seem a good option.