Single tube 100mm or 150mm long?

[OioMik]

Hello,
Do you know a seller who got single tubes (empty tube! Thanks for correction) of length 100mm or 150mm for canon ef?

I would like to use some finite microscope lenses but i would like to avoid to buy a bellow..

Thanks for the advices.

[Pau]

In our jargon a tube lens is a converging lens used to focus the "focussed to infinite" parallel emerging light rays of an infinite corrected objective onto the sensor or eyepiece. (in a microscope such a lens is placed inside the optical tube)

Reading your message text what you want is an empty extension tube (or a set of them). I wouldn't recommend Canon EF original or compatible ones with electric contacts because Canon EOS cameras (at least some of them) get locked when they detect the contacts but not a compatible lens mounted. Much better and less expensive is to use screwed tubes with a screw to camera adapter.
M42X1 and M52X0.75 are among the most popular and available threads.

[Adalbert]

Hi OioMik,

I use the following rings:
https://www.ebay.com/itm/313655840805?h ... SwT9lcz~H9

in this way:
viewtopic.php?p=245808#p245808

Best, ADi

[OioMik]

Nice design, thanks for help!

[Scarodactyl]

M42X1 and M52X0.75 are among the most popular and available threads.

M42 are as available as ever but I have found m52 surprisingly hard to find, just lots of listings with no stock left. For a full frame setup i got a set of Sony E mount extension tubes which had three threaded extenders between e mount male and female adapters, but their thread has an OD of something like 56.7, very odd. I was able to 3d print an adapter but it doean't seem like it is standard(?).

[OioMik]

It's not a big market, otherwise the ebay will be filled with metal threaded tubes :-))

[Scarodactyl]

Ebay is, indeed, filled with m42 threaded tubes along with a dazzling assortment of m42 helicoids and adapters galore.