Here is one scheme that works well and is made entirely of off-the-shelf extension tubes and adapter rings, plus some DIY flocking.
By the numbers, these parts are:
1. macro extension tube set with bayonet mount to fit camera
2. bayonet-to-M42 (42mm x 1.0mm thread) lens mount adapter
3. M42 extension tubes (two sets)
4. M42 to 52mm adapter ring
5. 52mm-52mm male-male reverse adapter ring
6. 49mm to 52mm "step up" ring (49mm male, 52mm female, used in reverse to fit the 49mm female threads on the normal front of the Raynox)
7. Raynox DCR-150 lens, reversed
8. 52mm to 43mm "step down" ring (52mm male, 43mm female, used in reverse to fit the 43mm male threads on the normal rear of the Raynox)
9. 55mm to 52mm "step down" ring with through threads, used here as a 52mm-52mm female-female reverse adapter
10. (optional) 52mm to M42 adapter ring (52mm male, M42 female)
11. (optional) M42 to 52mm adapter ring (M42 male, 52mm female)
12. 52mm to objective thread adapter (52mm male, objective thread female)
Parts #10 and 11, the two rings labeled "optional", are mainly to provide a few mm of extra separation between the objective and the Raynox DCR-150. Some tests have show that this makes a slight improvement in image quality.
Note: it is critical that you add flocking or baffles to kill reflections from the sides of the tubes and rings. Failing to do this can severely degrade image quality!
The most reliable way to see reflections is to simply point the assembly at a bright light, stick your eye where the camera sensor will be, and look for any bright rings surrounding the central aperture.
For illustration, here is a setup that uses a small camera to do the looking (with an extra set of tubes to block out external light). You can see in the live view on the back of the camera that this assembly has a lot of reflections that have to be killed.
Here is a test target to show the effect of glare. It consists of a white card with a hole poked in it, the hole exposing the interior of a closed box lined with black flocking. It's pretty safe to say that only an insignificant amount of light is actually coming out of that hole.
Shown here is the pattern of reflections, the image captured by the camera, and the histogram of that image. You can see that one set of reflections (from the M42 tubes) is responsible for overall veiling glare that would kill contrast in dark areas, while a large ring of reflections (from the bayonet mount at camera) is responsible for a bright ring around the outside of the field. (This was shot using a full-frame Nikon D800E camera. Full-frame Nikons are particularly vulnerable to the second problem because the mounting bayonet has a small diameter compared to the sensor dimensions.)
Here is the flocking used to eliminate the reflections shown above. The thin strip covers the mount ring at the camera, and the larger panel covers the entire inside of the string of M42 tubes. I used black Doodlebug cardstock . An alternative material is Protostar self adhesive fabric; there is also a newer Protostar sheet material that looks quite good but I have not worked with it yet. Both are available HERE.
In addition to these two sheets of flocking, I also added a circular sheet of flocking on the back of the objective adapter, to kill any reflections bouncing back off the Raynox. And just for completeness, I put a small dot of flocking on the end of a registration pin at the outer bayonet of the first set of tubes, which was responsible for the small isolated bright spot shown in the second row of the panel of reflections. Probably it was too small to visibly matter, but it was simple to eliminate just to be safe.
One more detail... Some extension tubes have bayonet fittings that do not fit as tightly as I would like. But in this tube assembly, it's very simple and effective to epoxy the M42 adapter (part #2) against the bayonet of the extension tubes (part #1). That leaves the entire tube assembly composed of screw threads, which are quite rigid.
As of this writing (Sept 2017), all of the parts here can be ordered from Amazon, except for the objective adapter which comes from an eBay vendor, and the flocking material. Total cost including the Raynox is about $170 plus tax, with shipping inside the U.S.
I hope this helps.
--Rik
