When focusing extremely close with my XH-A1, I can see some dust or something which is not on the front of the lens--I can't tell if it's on the rear element or sensor. Is this something I need to have serviced, or is there a safeish way for me to clean in myself?

If there is indeed "stuff" anywhere behind the front lens element or on the sensor, there is no way for a user to fix it. At least, not without shooting your warranty down in flames.

Intrigued as to how it could have got there, the lens modules are, as far as I'm aware, completely sealed units with no external openings whatsoever.

That said, I had a lens module replaced in my XL1s some years ago - the "new" sealed module when examined carefully looked like someone had flicked their cigarrette into it - white flakes of "stuff" everywhere.

The Canon tech was utterly gobsmacked.

So, it can happen.


CS

Are you sure that it is not just in the eyepiece? Lift the eyepiece up as far as it will go, on the bottom side you will find a little rubber plug. Remove this plug and carefully clean the lens with a cotton swab. Let us know if this alleviates your problems.

Are you seeing it on your monitor? If not, then it's on the viewfinder.

I doubt if a zoom lens can be hermetically sealed, so I guess if the cam was used in a dirty environment it is possible for particles to get inside.

Richard

I shoot at the beach in strong wind all the time and I've had a grain of sand appear on the inside surface of the front lens element twice. It shows up as a shadow in the footage. Rather than send the camera to canon and be without it for a several weeks (which is how long it took to resolve a jammed tape) I unscrewed the front lens element and a quick blast of air removed the grain.

Dirty environment? No, it's very easy to get dust on the sensor. I babied my XH A1, and only ever shot indoors, but I still got two big gobs of dust on it after just three weeks of ownership. I have to be careful to shoot at f/3.4 to avoid it; I'm glad I don't try to shoot macro very often. To see if your camera has dust, shoot f/9, infinity focus, on a monotone light subject, exposed to the right, then examine it at 100%