Min/Max focusing distance 28-70 f/2.8 with extension tubes

This information doesn't seem to be online.

What is the minimum and maximum focusing distance for the 28-70 f/2.8 (not 24-70) with the 12mm and 25mm extension tubes?

Anybody got the paper slip with the tubes handy?

Here you go:

http://www.bobatkins.c​om …graphy/eosfaq/c​loseup.htm

Very nice. Thanks so much!

Working distance 3-8mm. LOL

and that's just with the 25mm et. you wouldn't have any working distance at the wide end if you popped the 12mm on as well

12 and 25mm extension rings are to thick for many lenses.
I made thinner Canon extension tubes, with only 6 and 8mm thickness.
For DIY the EF contacts are heard to make, I have to try a other idea.

Yeah it's really annoying that the thinnest tube is 12mm, basically knocking most primes right out of usefulness

The 12mm works great for 85mm lenses and longer. But with lenses with floating elements / internal focussing one loose much of the near focus correction.
I love my DIY 6mm and 8mm tubes with lenses like the Zeiss 35mm/1.4, or my Minolta Rokkor 58mm/1.2 - and many others. 12mm are too long in many cases. Sometimes I am very happy to have some lenses in M42 mount, cause there I have even shorter extension tubes.