Nikon 16mm f/3.5 AI Lens Cap

[ArendV]

And as Bjørn said they are built-in so to "lose them" you need to open the lens and remove the filters.

]

Source
http://www.darinmcquoid.com/16mm%20repair.html

[Erik Lund]

Thank you for the link!
The filters appear to be flat,,,
I have only opened the older versions F, Pre AI and early AI, this one appears to be Ai and different internally,,,
I also see Roland's page stating another build length,,, 60.5mm vs. 62mm
I'm pretty sure I have removed the build in lens hood from the front without further disassembly.

[Bruno Schroder]

Thanks for the link, Arend. That's what the previous owner did.

I can now check if (hoping) the filter holding mechanism is still there. If it is still there, I have a chance to make a clear glass replacement, if I can get the thickness of the glass.

Erik, if the filter is a lens, should it appear on the schematic? http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/late70nikkor/fisheyes/16mmf35.pdf

[Bjørn Rørslett]

The filter is plane and has no refractive power.

An incorrect thickness will move focus 1/3 of the difference in thickness between the original and its replacement. Thus, possibly except for infinity focus, getting the replacement thickness wrong isn't that critical as long as you  focus the lens visibly.

I probably have a spare A2 or B2 filter for the 16mm f/2.8 fisheyes, it should be more or less the correct thickness and any optician should be able to trim it to the required size. You can get it for a nominal cost to cover shipping.  The slight change in w/b should be no problem with a DSLR anyway.

[Erik Lund]

Clearly the filters appear to be flat in the images of the Ai'ed lens,,,

What is your serial # ?

[Bjørn Rørslett]

Just checked with my friendly Nikon repair tech.

The lens cap is not a spare part, it is a sales item. The filter wheel is part number 20FL16-007.

[richardHaw]

http://www.yodobashi.com/ニコン-NIKON-カブセ式レンズキャップ-AF-Fisheye-16mm・10-5mm用/pd/000000102108601805/

see first if this fits
never say never

[Akira]

http://www.yodobashi.com/ニコン-NIKON-カブセ式レンズキャップ-AF-Fisheye-16mm・10-5mm用/pd/000000102108601805/

see first if this fits
never say never

I have this one.  The internal diameter is only 61mm, and filing off the ribs achieves 62mm.  It is a bit too small for 16/3.5 fish, unfortunately.

[Roland Vink]

I have the cap for the 16/3.5 fish-eye.
The outside diameter is 67mm and the height is 10mm.
I don't see the part number on the lens cap apart from 64K.

64K means the internal diameter is 64mm, K=slip-on (Kabuse) like the slip-on HK hoods...
You need something with an internal diameter of 64mm.

If I recall correctly the metal cap for AI and AIS 16/2.8 is 62K 61K, so too small. The metal caps later gave way to the plastic push-on cap which is currently shared with the AF 16 and 10.5mm fisheye lenses.

[Erik Lund]

Leica #39213 Slip on lens cap would be my best guess,,,

,,,Since it is 64mm inside diameter,,,

[Bruno Schroder]

An incorrect thickness will move focus 1/3 of the difference in thickness between the original and its replacement. Thus, possibly except for infinity focus, getting the replacement thickness wrong isn't that critical as long as you  focus the lens visibly.

I probably have a spare A2 or B2 filter for the 16mm f/2.8 fisheyes, it should be more or less the correct thickness and any optician should be able to trim it to the required size. You can get it for a nominal cost to cover shipping.

I thought about using an old Nikon or BW filter but the thickness is 2.2mm and looks too much for the filter holder, which is still there, btw.

Did your friendly tech check if the filter wheel is still available? If not available, I would gladly accept your friendly proposal.

[Bjørn Rørslett]

He did check, but only the national inventory.  No hits there. You might try an e-mail to NPS or Nikon Europe since you have the parts number.

If you wish the alternate suggestion, just send me a PM and I'll start looking for spare(s). I do know with certainty there are some, but the item must be retrieved

[richardHaw]

if ever i find one in any condition and in reasonable price, should I just get it (max $45)?

i sometimes get lucky in the junk shops.

[Bjørn Rørslett]

Stockpiling oddities is always an option, if you have the storage space for it. The strangest stuff can be highly attractive for someone desperately seeking elusive items.

[richardHaw]

Stockpiling oddities is always an option, if you have the storage space for it. The strangest stuff can be highly attractive for someone desperately seeking elusive items.

you are correct. i remember somebody asking for the drop-in filter holder and I actually found 2 of them for $4 each

i will do that from now on.