I shoot mostly documentaries and the standard lens on the XF100 is not nearly wide enough for off the shoulder verite-type shooting. The Canon Wide-Converter WD-H58W makes a world of difference. It will probably stay mounted on my camera 95% of the time.

The problem with this is that Canon says "You can not use filters...with the wide-converter." There aren't any threads on the front of the lens and the supplied hood would be in the way even if there were threads.

Using a $400 lens without any protective filter seems like asking for trouble and then there is the often discussed ND issue with this camera that cries for external ND filtration.

Has anyone found a work around or other solution for this dilemma?

It's pretty wide out of the box compared to some, but yes. I use the Raynox .66, which does have threads. The problem with filters on top of the wide is that it's wide enough at the wide end to catch the edge of the filters, and focuses close enough to see any smudge on the filter. Canon probably thought adding anything in front was pointless. The Raynox doesn't screw on direct, you have to put an intermediate, which can be an empty, IR or ND filter, and that would also solve your where to put the ND issue, but it does increase the standoff so you get some vignetting at the very wide end - still much wider than without where the vignetting stops. I wouldn't leave the wide on all the time, you lose too much light and it further flattens an already flat image.

We shoot with XHA1 and A1s and have fitted Canon WD-H72 wide convertors to all cameras and they stay mounted all the time.
First impression was the great colours.

With their lens hoods in place we haven't found any trouble re lens protection, I did read somewhere that the front glass has a protective finish,
but the lens cap is always closeby. We have no ND problems and always carefully clean the convertors the night before, under a lamp.

With the extra weight at the front the cams needed rebalancing on our Miller Compass 15 tripods with Manfrotto Lancs.
So I ran a 4cm thin strip of white adhesive tape on the lower left side of the cams, and marked the balance points on it.

Cheers.

I have the xf105 and use the Century .55x adapter. It also does not have a screw mount on the front, so I think you'd need to use rails and a matt box to get it done. It's a beautiful lens and I just switch on the menu item for the Canon wide when I use it.

Schneider found a nice option for protecting the lens, it's a rubber lens cap. It goes on tight and easy, no threading, obviously. Biggest problem is no lens shade, so you have to be cautious of flare.

But yes, I agree that focus on both this and the xf305 at wide angle is so deep, that I have to be very careful of getting anything on the lenses. They show up dirt, rain drops, anything. I've lost a number of clips due to not checking, here in the rainy Pacific NW. I keep the cap on the lens and the lens pointed down, as much as possible when out in the field. Even then you have to watch out for splashes coming up.

Just checked out some before/after videos with the WD-H58W, and there appears to be some strong barrel distortion in this example. I wonder if there are tools out there to fix that, and how much picture you'd lose doing so?

Canon XA10 With WD-H58W Wide Angle Lens Comparison on Vimeo

Yep, barrel distortion in all these kinds of WA lens. I believe that Premiere can fix that to some degree. I've not needed to try yet.