Vintage filters

**Denver** · 04-18-2021, 05:47 AM - **1 Like**

it is most likely a bottom plate used in packing a filter in a box. Doubt it is a filter at all.

CountryGirl · 04-18-2021, 08:12 PM

@ 35mmfilmfan - I do believe it is a center spot diffuser -- not particularly exciting -- and it measures about 49mm. Short of breaking the glass on another filter and gluing the diffuser into it (and hoping to get it absolutely plumb), I don't see mechanically how to fit it into something else. Retaining ring? Do the two threaded pieces that hold the colored glass screw into each other?

---------- Post added 04-18-21 at 08:13 PM ----------

Originally posted by Denver

it is most likely a bottom plate used in packing a filter in a box. Doubt it is a filter at all.

@Denver Yes, I tossed it. Just wanted to be sure I wasn't overlooking something.

35mmfilmfan · 04-19-2021, 05:38 AM

Originally posted by CountryGirl

@ 35mmfilmfan - I do believe it is a center spot diffuser -- not particularly exciting -- and it measures about 49mm. Short of breaking the glass on another filter and gluing the diffuser into it (and hoping to get it absolutely plumb), I don't see mechanically how to fit it into something else. Retaining ring? Do the two threaded pieces that hold the colored glass screw into each other?

---------- Post added 04-18-21 at 08:13 PM ----------

@Denver Yes, I tossed it. Just wanted to be sure I wasn't overlooking something.

Yes, with many filters, the actual filter itself is held inside the mount by a threaded retaining ring, on the 'female' (no gender issues intended or specified !) side of the filter mount. There are often two diametrically opposed slots or indentations in this ring - they can, with care, accept the pointed ends of geometry set calipers or dividers, and the ring unscrewed. A lens spanner should also do the trick, should you have one sitting around somewhere. I too feel it is a centre spot diffuser, but the surround to the spot looks more clearly defined and opaque than others I have seen.

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04-18-2021, 05:47 AM - 1 Like	#16
Denver Site Supporter Join Date: Jan 2020 Location: Denver Colorado Posts: 221	it is most likely a bottom plate used in packing a filter in a box. Doubt it is a filter at all.

04-18-2021, 08:12 PM	#17
CountryGirl New Member Join Date: Apr 2018 Posts: 22 Original Poster	@ 35mmfilmfan - I do believe it is a center spot diffuser -- not particularly exciting -- and it measures about 49mm. Short of breaking the glass on another filter and gluing the diffuser into it (and hoping to get it absolutely plumb), I don't see mechanically how to fit it into something else. Retaining ring? Do the two threaded pieces that hold the colored glass screw into each other? ---------- Post added 04-18-21 at 08:13 PM ---------- Originally posted by Denver it is most likely a bottom plate used in packing a filter in a box. Doubt it is a filter at all. @Denver Yes, I tossed it. Just wanted to be sure I wasn't overlooking something.

04-19-2021, 05:38 AM	#18
35mmfilmfan Pentaxian Join Date: Oct 2016 Location: Norfolk, UK Posts: 4,339	Originally posted by CountryGirl @ 35mmfilmfan - I do believe it is a center spot diffuser -- not particularly exciting -- and it measures about 49mm. Short of breaking the glass on another filter and gluing the diffuser into it (and hoping to get it absolutely plumb), I don't see mechanically how to fit it into something else. Retaining ring? Do the two threaded pieces that hold the colored glass screw into each other? ---------- Post added 04-18-21 at 08:13 PM ---------- @Denver Yes, I tossed it. Just wanted to be sure I wasn't overlooking something. Yes, with many filters, the actual filter itself is held inside the mount by a threaded retaining ring, on the 'female' (no gender issues intended or specified !) side of the filter mount. There are often two diametrically opposed slots or indentations in this ring - they can, with care, accept the pointed ends of geometry set calipers or dividers, and the ring unscrewed. A lens spanner should also do the trick, should you have one sitting around somewhere. I too feel it is a centre spot diffuser, but the surround to the spot looks more clearly defined and opaque than others I have seen.