What exactly are they and how do they work? Do the cut down light? I dont really understand it. I ran across one here: ebay (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4687&item=3861476622&rd=1)

thanks.

What exactly are they and how do they work? Do the cut down light? I dont really understand it. I ran across one here: ebay (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4687&item=3861476622&rd=1)

thanks.

An extension tube is a hollow tube that fits in-between the camera body and the lens, thus moving the lens further out. This allows the lens to focus closer than it normally does although you lose infinity on the oher end. It is a good way to get macro abilities if you don't need a flat field.

Yes, it does cut down on the amount of light but, as it has no optical elements, it doesn't change the quality of the lensb

Exactly. Less expensive way to get into macro, and it can also be good for long telephoto lenses if you need to get closer than the lens can focus. With an extension tube you won't be able to focus to infinity, so you can't leave it on all the time - only when you're using it.

I use them with my macro lenses, They come in really handy. I would suggest getting one that is specific to your camera brand if using autofocus. With my canon tubes I can still use autofocus on my macro lenses when I need it.


Magoo