Canon Extension Tubes

[BobbyR]

Hi Bob:
Thank you for you replying to my recent question asking which Canon DSLRs  are roughly equivalent to my Canon A2E.  I purchased the 50d and so far very happy with it.  I also purchased a Canon 17-40 lens for the camera.

Now I have a question about extension tubes.  The 17-40 manual states that it's compatible with extension tubes EF12 II and EF25 II.  I have the older EF12 and EF25 tubes.

I've read several forum threads that suggest, but not definitively that the older tubes can be used with only EF lenses while the Mk II tubes can be used with EF and EF-S lenses.  Is this correct?  Or do I need to purchase the updated design for my 17-40 lens?

Thank you again for your time.
Bob

[Bob Atkins]

Well, the 17-40 is an EF series lens, so it will work with either the original or MkII tubes.

The reports are correct that you need the MkII extension tubes for use with EF-S series lenses, but either tubes will work with EF lenses.

It's easy to tell. If you can mount the lens on the tube, it's OK. If you can't, it's not! You can't physically mount and EF-S lens on the original tubes. There's not eough space for the protrusion at the back of the lens.

[KeithB]

Just to jump on here.  What are the advantages/disadvantages of extension tubes vs closeup lenses?

[Bob Atkins]

That's probaly best fully answered here:

http://www.bobatkins.com/photography/eosfaq/closeup2.htm

Extension tubes are good for reducing the minimum focus distance of a lens and can be used even with long telephotos with large front elements. So you can reduce the minimum focus distance from, say, 10ft to 5ft. They're OK for macro work with sorter focal length lenses, but when used with zooms the lens needs to be refocused every time the focal length is changed, and the amount of focus shift can be large, enough to require that the whole lens be moved back and forth. When used with short focal length lenses, they result in a loss of lens speed.

High quality closeup lenses give excellent quality and when used with zooms, focus is held as the lens is zoomed so it's much easier to compose a shot. There's also no loss of lens speed.