There is more than one Canon 8-48 mm model. (there's more than one Rainbow model also) You'll have to show us exactly which one you mean. I believe the Canon PH6x8-II is identical to the Rainbow H6x8-II.

Other people have modified the Rainbow H6x8-II by affixing an m43 adapter to the rear with three tiny screws, but I think it's far better to modify this lens by securing the lens's own C-mount threads to the back with six new screws.

Remove the rear plate. Separate the C-mount threads from the black CS-mount adapter. It's glued, so you might need to drop the entire rear plate, C-mount, and CS-mount adapter assembly in boiling water to soften up the glue enough to unscrew the CS-mount adapter. Clean out the grease. Remove the rear housing. (it's held on by six screws) Place the now-separate C-mount threads in the rear housing, and use a drill press with an M2.1 bit to drill six holes in the C-mount through the existing six holes in the rear housing. You'll use those existing six holes as guides, and drill from the inside of the rear lens housing towards the back. Then you need six M2 x 8 screws with heads no taller than 1.2 mm. I used flat-head screws. You need a C-mount adapter with a flange no thicker than 1.0 mm. Most of the so-called slim and super slim C-mount adapters have a 1.4 mm thick flange. The thicker flange won't allow you to make this lens parfocal, even using the lens's back focus adjustment.

White metal? The 2-in-1 M42 and C-mount to m43 adapters have a flange that's far too thick for this lens - 5.2 mm. You still haven't told us which Canon lens you're using.

I've successfully modified dozens of Rainbow H6x8-II, which is the same lens as your Canon version. The Canon version is much more rare...let me guess, did you buy it off Ebay?

The C-mount adapter I've used looks like this: http://www.ebay.com/itm/220873821595

I've sold my modified lenses on Ebay before: http://www.ebay.com/itm/300870921143

There's many pictures of the mod here on PView.

Thicker is stronger and a better solution for a permanent mount on the lens. To get infinity focus, you need to replace the rear metal ring (with the three screw holes) with the c-mount adapter. I drilled 3 holes in the adapter to match the 3 holes of the metal ring, and used a grinding tool to grind out the surrounding area of each hole so that the screws are flush with the adapter. That's the only way it will work to attach lens to the GH2 / GH3.

As I see more and more, I need a thin c-mount>m4/3 adapter so that the things work finally.

BUT: what confuses me is that even holding the lens by hand straight to the body of my GH2 (without c-mount adapter attached!), it still can give focusing less than 1 meter distance from an object. Note that I tried that with the c-mount thread removed from the lens, so only the black ring part with the six screws touches the body of GH2!

Hope the Pentax Cosmicar model is much better and easier to modify...

See post # 2 of this topic for photos. That's the whole mod. The C-mount adapter is not permanently attached. It just screws on to the C-mount threads.

@producer, if you want to avoid the hassle, I can trade you my modified Rainbow H6x8-II for your Canon 8-48mm.

Let me know.

Here is everything: the lens and the silver mount thread removed and my c-mount>m4/3 adapter.

As I wrote already, the c-mount>m4/3 adapter obviously must be the thinner version. Once I order such a type, then I think everything will be ok.

Yes, too thick I realised already. How to unscrew the c-mount from the cs-mount? Boiling water?

That is not a CS Mount adapter, but a macro extension, since the end is still a C-mount thread. You will need to heat it up to melt the glue and use pliers to unscrew.

The silver c-mount thread of the lens is separated already. After the boiling water I unscrewed its parts very easy without any efforts.

Well, the next absurd: even after getting the result exactly as shown on the pictures of balazer from the 2nd post, the lens doesn't give an infinity focus. Then I removed the c-mount>m4/3 adapter from my GH2 and put the lens right on the GH2's bayonet. With other words, the black 6-screwed circle part of the lens touches the GH2's bayonet. This time an infinity focus is almost available, BUT here is the next absurd: the picture still shows circle vignettings when the lens is zoomed-out (i.e. no zoom) even in ETC mode. How is this possible??? I'm with Moon Trial 3, don't know if the ETC covering is an issue with this patch.

Of course, I adjusted it to its maximum outer position, so that's not the reason.

Really don't know what to do more...