Ben Z
Veteran
So far I've seen two solutions to getting an IR filter onto a C/V 15mm.
One is to use some kind of material to wedge the filter inside the shade fins. Since the front element bulges out, that means either reversing the filter or fixing it forward enough that the glasses don't touch. It also means having to undo and redo the operation if you also use the lens with film (don't want cyan vignetting for no purpose).
The other is a very nice but costly adaptor made by a talented machinist, which uses a larger filter, reversed, which means that to have the anti-reflective (and scratch-resistant) surface face forward, you have to undo the spring clip or retaining ring in the filter mount and reverse the glass, risking scratching the filter in the process, and making it less usable on another lens.
So I set about and devised my own adaptor, which in principle adds 39mm female filter threads to the lens without vignetting on full-frame.
First, I removed the glass from a 39mm B+W UV filter, of which I have some spares. (I like the B+W or Heliopan filters because they're made of brass vs aluminum, and other brass filters won't bind easily in their female threads.) I used a rubber stopper to unscrew the glass retaining ring, placing the filter flat on a table on top of a rubber glove to keep it from sliding. You could also cut diametrically-opposed notches in the ring with a Dreml bit and use a spanner to unscrew it, as the ring and glass are to be discarded.
Next, I ground off the male threads on the rear of the filter rim. There is a flat landing after the threads which can be used as a visual guide to keep the surface level. (This step is necessary to avoid vignetting either on an M8 or a film body).
Finally I affixed the adaptor in place with a tiny amount of ATV silicone adhesive, although if a truly permanent installation is preferred, epoxy could be substituted (NOTE: DON'T MAKE IT PERMANENT UNTIL YOU'VE MADE SURE IT DOESN'T VIGNETTE ON YOUR FILM LEICA, as it's not beyond possibility that not all filter rims are identical in thickness) A 39mm Leica UV filter can now be screwed in place without reversing, and does not vignette. When I want to use the lens on my M6 I can simply unscrew the IR filter, as the adaptor does not vignette on full-frame.
One is to use some kind of material to wedge the filter inside the shade fins. Since the front element bulges out, that means either reversing the filter or fixing it forward enough that the glasses don't touch. It also means having to undo and redo the operation if you also use the lens with film (don't want cyan vignetting for no purpose).
The other is a very nice but costly adaptor made by a talented machinist, which uses a larger filter, reversed, which means that to have the anti-reflective (and scratch-resistant) surface face forward, you have to undo the spring clip or retaining ring in the filter mount and reverse the glass, risking scratching the filter in the process, and making it less usable on another lens.
So I set about and devised my own adaptor, which in principle adds 39mm female filter threads to the lens without vignetting on full-frame.
First, I removed the glass from a 39mm B+W UV filter, of which I have some spares. (I like the B+W or Heliopan filters because they're made of brass vs aluminum, and other brass filters won't bind easily in their female threads.) I used a rubber stopper to unscrew the glass retaining ring, placing the filter flat on a table on top of a rubber glove to keep it from sliding. You could also cut diametrically-opposed notches in the ring with a Dreml bit and use a spanner to unscrew it, as the ring and glass are to be discarded.
Next, I ground off the male threads on the rear of the filter rim. There is a flat landing after the threads which can be used as a visual guide to keep the surface level. (This step is necessary to avoid vignetting either on an M8 or a film body).
Finally I affixed the adaptor in place with a tiny amount of ATV silicone adhesive, although if a truly permanent installation is preferred, epoxy could be substituted (NOTE: DON'T MAKE IT PERMANENT UNTIL YOU'VE MADE SURE IT DOESN'T VIGNETTE ON YOUR FILM LEICA, as it's not beyond possibility that not all filter rims are identical in thickness) A 39mm Leica UV filter can now be screwed in place without reversing, and does not vignette. When I want to use the lens on my M6 I can simply unscrew the IR filter, as the adaptor does not vignette on full-frame.
Attachments
Last edited:
ywenz
Veteran
Ben Z did you end up buying a M8?
Ben Z
Veteran
Yessirree bob. Youbetcha. Sure did. Can drive a truck through the hole in my bank account. PS, just what we need in Chicagoland, another Tigers fan :bang: 
Last edited:
jaapv
RFF Sponsoring Member.
Brilliant, Benson! :angel: *thumps head* Why was I too stupid to think of that!
GrahamWelland
Well-known
How about a picture of this contrapation? Sounds like a very useful approach - i.e. adding a filter ring basically.
Ben Z
Veteran
I had a link to one, but now I figured out how to put it right in the thread, so just click on the thumbnail in the original post.
AGeoJO
Established
Thank you very much Ben. I have been using my CV 15 naked..... Seems simple enough that I may want to do it on my own . Now I need to get a 39mm filter. Time to call Tony, I guess.
. Now I need to get a 39mm filter. Time to call Tony, I guess.