Camera Labs

Anyone ever use them? And also, are they needed with a macro lense?

Random Factoid: It's Sunday right now and the washer sounds like a helicopter. Stupid energy efficient washers.

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Sorry, mate, I believe I just ate your pudding cup.

No extension tubes needed with a macro-lens.
But you can also use them to extend the magnification of the macro-lens.
Unfortunately the IQ will suffer esp. when just using a "normal" lens or a zoom, as you'll leave the parameters that this lens was corrected for.
Alternatives:
Use a well corrected close-up lens to screw in front of your camera-lens (Canon 500D at around 100$).
Or use a tele-converter (more expensive) that improves magnification by the same factor as the focal length of your lens (max. 2x), so if your lens went down to say 1:3.8 it will go down to 1:1.9 with a 2x tele-converter.
IQ-wise the close-up lens might be the best alternative, as the tele-converter halves the resolution of your lens.

But to answer your question directly: no, I have no experience with extension tubes

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses