There are two different tube lengths available the MDEX-11 at 11mm and the MDEX-16 at 16mm, Macro extension tubes are inserted between the lens and the camera body and increase the distance between the lens elements and the sensor enabling users to focus on subjects much closer to the camera.
A chief advantage of using dedicated extension tubes is that they have pin contacts to pass information between the camera and the working lens. This means being able to use auto-focus and transmit aperture info to the camera while the tube is attached.
On the plus side, extension tubes have no optical elements to interfere with the optical quality of the original taking lens. On the minus side, the extra extension will increase the exposure somewhat. Expect about a 25% loss in shutter speed with the 16mm tube attached.
The chart below shows the magnification changes possible with each extension tube:
The sample images below illustrate what this means in practical terms using the XF35mm lens alone and with each extension tube.
|Fuji 35mm f/1.4 lens|
|Fuji 35mm f/1.4 lens plus 10mm extension tube|
|Fuji 35mm f/1.4 lens plus 16mm extension tube|
|Fuji 35mm f/1.4 lens with both 11mm and 16mm extension tubes|
Extension tubes can also be used in tandem for even greater magnification. Used together the 11mm and 16mm would be a 27mm extension.
For comparison here is what a 1:1 Zeiss Touit 50mm macro looks like:
|Zeiss Touit 50mm Macro|
And just for fun, here is what that same macro looks like with both the 11mm and 16mm extension tubes attached:
|Zeiss Touit 50mm Macro with both 11mm & 16mm extension tubes|
The MCEX-11 and MCEX-16 will be available for $99.95 around mid-December. A similar set made in China by Folga is available for immediate delivery for $49.95 on Amazon.
A similar set, the Fotasy FXME Auto Focus Marco Extension Tube 10mm 16mm 26mm for Fujifilm X Mount, is also available on Amazon for only $35.95.
I am probably not going out on a limb by expecting the Fuji product to be made to a higher standard of precision. Then again, at a much higher price.