Original drop-in filter for EF 600 MK II

[steinrr]

I have been trying to find out what the original drop-in filter for EF 600 MK II is.

The manual says:

"A 52(WII)-series drop-in gelatin filter holder with a glass filter is included with the lens.
The Drop-In Screw-Type Filter Holder 52(WII) and Drop-In Circular Polarizing Filter PL-C52(WII) are also available (sold separately)."

I suspect it might be this:

What I don't understand is that the manual says "with a glass filter". Does the filter in the link provided also come with a glass? And is this glass something that is not removed but will stay there always - even if you add gelatin filters?

I also found this:

I think it is the same, but here it says: "These glass-backed holders accept up to three commercially available cut-to-size gelatin filters for rear-insertion lenses"

Does this "glass-backed" refer to what the manual call "glass filter"?

I hope someone can enlighten me...

[Links replaced per Community guidelines]

[steinrr]

I bought a used lens, and the holder was included. But the glass filter was scratched. But the store found a 400mm that had the same filter which was not scratched and gave me. But I was wondering if I should buy a new one, just to have a backup - since the lens is old and it might be difficult to get hold of in the future. So I am trying to find out what the original is.

[normadel]

Are you planning on using colored gelatin filters? If not, you never need take the filter holder out of the lens, so the glass can't get dirty or scratched. You DO want to always have the filter holder inserted to keep dirt out of the lens, besides the optical reason..

[steinrr]

No, I won't use any filters with it. Just afraid that somehow it will get scratched and that Canon won't produce them anymore.

[normadel]

Like I said, if you don't take it out it cannot get scratched. End of story.