View Full Version : 100mm f/6.3 Wide Field Ektar Filter Size

Peter York
29-May-2010, 14:59
Hi all,

I have finally had it with my Lee snap on filter system (the one employing a rubber band to attach the filter holder to the lens) and I will replace it with a Cokin P system (I'm using this for backpacking, so I opted out of the Lee foundation kit due to bulk/weight).

One of my lenses is the 100mm wide field ektar. A search on this site yielded a comment that the lens has a 40mm thread size, while Kerry Thalmann's site mentions an odd size (approx. 39.5). Does anyone know which of these is correct? If the thread is not a common one, do I have any options for a slip-on adapter other than having S.K. Grimes custom make one? Finally, have any of you experienced vignetting issues with this lens/filter system combination (i.e., should I find a wide angle step-up ring, saw off a second filter slot, etc.).

Any and all comments are appreciated. Thanks!

29-May-2010, 16:52
I screwed a 39mm to 49mm filter adapter into mine. Never had another problem. I wouldn't try to screw it in too tight - might be hard to remove.

Doremus Scudder
30-May-2010, 03:32
I believe the 39.5 mm thread is unique to this lens. Kodak originally made a "special adapter ring" for the WF 100's 39.5 thread to Series VII. One luckily came with mine, so I just bought a Series VII to 52mm step-down ring. This set-up, however, is a little long and vignettes when at the edge of the lens's coverage. In those cases, I often take everything off and just hold or tape a filter over the lens.

If you can find the special adapter, that would be a good solution. In lieu of that, I would likely try rfesk's solution, adding a bit of teflon pipe tape to take up the slack between the different thread pitches and, of course, not screw it in too tight. What you don't want to do is damage the threads in the lens itself.

In fact, I might just order a 39-52mm step up ring for mine and see if that solves the vignetting problem!


Doremus Scudder

Peter York
30-May-2010, 08:55
Thanks Bob and Doremus,

I'm getting into GND filters with transparency film and the tape/rubber band lee holder/kludge methods are no longer adequate. I will try the 39mm rings and if vignetting is problematic, then I'll probably hot glue a larger ring on the outside barrel to connect the lens to a filter holder.


Bernard Kaye
30-May-2010, 12:21
39.5mm.FINE is size & thread for many Leica and some Zeiss older (e.g. Protar) lenses, filter size for Leica and shutter acceptance thread & other for Zeiss.
You can force a 39.5mm.STANDARD onto or into a 39.5mm.FINE but it may ruin both female & male threads.
Tiffen did long ago make 39.5mm.FINE adapters; you find it (them), fall on it (them).
Good luck,

Bernard Kaye
31-May-2010, 12:15
I goofed & badly: the thread is 39mm.FINE for many Leica filters and certain older Zeiss equipment: 40.5 for certain later and older Zeiss equipment but do not force FINE & STANDARD threads together.