Neutral Density Filters for Contaflex

[Inapickle]

Hi,

I use third party macro/close-up filters attached to a trail camera for filming wild birds, and other small animals, at close range. With the trail camera I have at present I am using vintage 27mm contaflex filters. I have two sets (+1, +2, +3) one made by Bittco (Super Vemar) and the other Vivitar. I use a Zeiss-Ikon (S27) Sykylite filter with the glass removed as an 'adapter ring' for attaching the macro filters to the trail camera lens. The results are quite good considering . This video shows the method and some sample clips:

Campark TC02 Macro Filter Modification

That said, the auto-exposure control on these trail cameras (invariably aperture priority) has it's limitations and struggles in bright sunlight.

I'm wondering, were 27mm neutral density filters ever produced for Contaflex filters ? I regularly scan EBay but have never seen one listed. I've thought about using a larger size ND filter (say 37mm) attached to the macro filter with a step-up ring, but one thing I've found with these Contaflex filters is that the low profile, fine pitch thread is not compatible with 'generic' step rings, at least those I purchased on EBay (from China).  

Edited April 26 by Inapickle

[m42dave]

Looking at some Contaflex literature, there is no mention of a ND filter being offered. I have seen other 27mm ND filters, though (Heliopan, Hoya, etc.).

Perhaps you could use Series V filters? There are old 27mm threaded to Series V step-up rings available on eBay (I used to have a Tiffen one for a Smena-8) that should be compatible. The Ser. V filters are mostly drop-in type but they were some available with threaded mounts too (e.g., Vivitar) including ND.

Edited April 26 by m42dave

[Inapickle]

Thanks a lot. I'll look into the Series V filters. Yes, Heliopan do offer 27mm ND filters but they are rather too pricey for this application - around 65 $US a piece (B&H). The Zeiss-Ikon (S27) polarizing filter (342 Contapol Polar 3X) comes up quite often on Ebay, but looking at the photos I'm pretty sure it would vignette when stacked on a macro filter plus the 'adapter ring'. Thanks for your suggestion anyway.

Edited April 27 by Inapickle