Nikon 8mm f/2.8 Ai - filter carousel

[Erik Lund]

You can't add much to the thickness of the filter I think,,, you will loose focus range.

[Kuri]

Thanks Akira, good idea. I will try that sometime too.

Longzoom, Yes, I meant you, not Thomas.
Those are all go points, thank you for your ideas on this.
This is an excellent point about the gel contacting the glass, I will keep an eye on that. It looks like the Wratten gel filters I have lay very flat, and given the 20mm diameters, I am estimating they will stay separated.
I don't see any way to remove these glass filters with a knife, it would most likely result in breaking the filters. The glass is so tightly inserted into the hole that there is no room for even a very thin exacto knife blade.
You have removed these filters from this lens before?

Erik, Good point. I will give it a try and compare focus range. Thank you.

[longzoom]

Kuri, I removed 3 of them thru small hydraulic press, using middle pushers, made of wood, about 19mm and 24mm, from the opposite side.  It is very ease, if you know how, (be careful  not to deformed the main ring!),  or ask experienced personnel. Knife I used after all, to clean the saddle from remains of glue and paint. LZ   (BTW, the gel filters will stay flat and firm at the winter, what about +40?)

[Kuri]

Wow !:-) You have removed filters from this lens? In your case, why did you remove them?

[longzoom]

One of them was pola - clear mistake, it covered about 1/3 of the circle, center only. Was usable to some degree, in very rare cases. Second one was 5x gray dark B/W filter, I needed way long exposure, for some color  project. The last one was +2 or 3 extra thin diopter lens. With this one I moved closer, with significant loss of border circle, coze I was able to use the center only, about 12mm in diameter, due to its thickness to the borders. But it was not important - I got my art effect, by enlarging the central part of the full circle, B/W film of ISO 16 let me do it. In this last case I should use another fish, 15-16mm with the same effect from the full frame, without heavy cropping, but I had nothing else with me, unfortunately!  LZ 

[longzoom]

Oh, forgot to mention: if someone, anyway, wants to try the polarizing filter, do not even open any pola unit - there will be only 1-ring piece, turning by gears. You need a regular 2-rings filter from a Microscope collection, extremely delicate, thin and fragile one. I used to turn it by the teeth stick, a lot of try without any visible stable result, as I have already said. But if one is driven by curiosity, why not, really! Good luck!  LZ

[bobfriedman]

i wouldn't even use a polarizer with lens less than 20mm focal length.... even 20mm is uneven.. why would you ever think a polarizer was the way to go with an 8mm fish??

[longzoom]

Thank you, I knew that, believe me, but for reason of curiosity! And hope - the filters are very close to very curveted inner elements - the effect could be drastically differentiated from my own experience. Did not happen, unfortunately. Very interesting to repeat it today, with a new generation of pola filters. I used very old linear ones, who knows... THX!  LZ 

[Akira]

i wouldn't even use a polarizer with lens less than 20mm focal length.... even 20mm is uneven.. why would you ever think a polarizer was the way to go with an 8mm fish??

If a PL filter is used within the optical system, the angle of incident of the light can be much more perpendicular to the filter.  So, the effect may be more even.

[longzoom]

Exactly, Akira!  More than 25 years ago I've parted with this lens, so, can't try a new CPL on it, behavior of such could be completely opposite to the old one I've already tried. Nobody knows, so far. THX!  LZ

[Akira]

Exactly, Akira!  More than 25 years ago I've parted with this lens, so, can't try a new CPL on it, behavior of such could be completely opposite to the old one I've already tried. Nobody knows, so far. THX!  LZ

LZ, now that there are full frame mirrorless cameras, one could use a PL filter behind the lens using a mount adapter such as this (I purchased one accoding to Klaus' advice).  This is a m4/3 version but there is a Sony FE mount version, too:

https://www.bhphotovideo.com/bnh/controller/home?O=email&A=details&Q=&sku=1190856&is=REG

[bobfriedman]

If a PL filter is used within the optical system, the angle of incident of the light can be much more perpendicular to the filter.  So, the effect may be more even.

good point, i failed to take that into consideration... thx.

[Kuri]

Some progress here. Forget about the gel filter idea now. A picture is worth a thousand words:

[bobfriedman]

you did it!

[longzoom]

LZ, now that there are full frame mirrorless cameras, one could use a PL filter behind the lens using a mount adapter such as this (I purchased one accoding to Klaus' advice).  This is a m4/3 version but there is a Sony FE mount version, too:

https://www.bhphotovideo.com/bnh/controller/home?O=email&A=details&Q=&sku=1190856&is=REG

  Thank you, very interesting! Slowly-slowly, this way or that, we are moving to unification of all kinds of mounts, I somehow believe. LZ