Has anyone tried adding a filter holder to lens adapters?

hindesite wrote:

BBbuilder467 wrote:

petrochemist wrote:

I've recently seen several lens adapters with built in ND filters.

Potentially useful for lenses with odd size or no filter rings..

For most lenses I can't see any advantage in having them there rather than in front of the lens,

Oh really? Try getting a filter for the front of a 800/5.6 Nikkor, then...

(yeah, I have one, it was quite expensive).

I did say most lenses. Both extremes of focal length can cause issues, the Nikon 6mm /2.8 fisheye (with a 220 degree FOV) would I suspect prove even more difficult than long lenses! - I don't have that fisheye, (it costs far more than all my photographic gear combined one sold for $160,000 in 2012) but filters are an issue with the various fisheye's I do have (none of them have filter threads)

but it's prompted the thought that it might be useful for IR shots etc to have the ability to fit a filter inside some of my adapters...

Has anyone tried this?

It wouldn't be difficult to machine an existing adapter to accept a filter inside. Anyone with a lathe could do it. The problem would be finding a consistent size in filters to use.

No machining necessary - 40.5 dia filters fit directly inside some EF-M4/3 adapters, for example. It is easiest to push a ring from a UV filter into the adapter, and then screw your filter onto that.

Useful for ND filters for video, and some other situations. Not so useful for PL filters, since it is harder to rotate them (get a Fotodiox filter for that).

Problem is remembering the filter is installed, and in which adapter

I see a few comments about "degrading IQ" and affecting focal length - both issues are overblown IME, Putting any filter on the front of a lens often reduces IQ in any case, particularly for telephoto use.

Seems reasonably likely that any adapter is being used with mirrorless, so any effect on focus is automatically corrected. No big deal.

I'm not sure if any of my many filters are 40.5mm ones, but this sort of approach sounds promising!

Perhaps I'll be able to get away with a 40.5-37mm step down - I have a fair range of 37mm filters. I'll move this up my list of projects