I've gotta get in on this one. I've tried the 3 part extension tubes on my 400 telyt and can focus to about 10~12 feet, BUT being the "Overkill Gadget Freak" that I am, I also used the 400 on my Bellows R, which balances almost perfectly. The R Bellows gives an infinitely adjustable extension from about 30mm minimum, to about 130mm maximum. With the built-in macro rail for the tripod mount and racked out all the way forward, I can use this set-up on my Leica table-top tripod with late large head and it is very stable! Anyone wanting pics of this setup, give me your e-mails and I'll get them to you. With this combo, close focussing is about 2 1/2~3 feet from the front of the lens to your subject! Art Tafil natstek@xxxxxxx