I agree with James - get a sacrificial filter and remove the glass, retaining only the metal ring. Then, get a sacrificial Cokin filter and cut a hole in the center. Glue the metal ring in place. After the glue cures, you can then screw any conventional filter you want into this 'utility mount'. Two concerns. First, flare. The ideal sacrificial Cokin filter is one that is nearly opaque so that light cannot enter through the Coking filter and then bounce around between the ad hoc filter and the lens. If nothing else, perhaps apply a little black paint to opaque the area surrounding the mounting ring. Second, if I were doing this, I think I would select a glass filters (both the sacrificial filter from which I cannibalize the metal ring and the filters that I would use with this setup) that are at least one standard size larger than the front diameter of the lens on the camera. I would worry about this setup causing vignetting, and oversizing the filter would tend to avoid that problem. -----Original Message----- From: owner-photoforum@xxxxxxxxxxxxxxxxxx [mailto:owner-photoforum@xxxxxxxxxxxxxxxxxx] On Behalf Of James Schenken Sent: Tuesday, January 29, 2013 9:41 PM To: List for Photo/Imaging Educators - Professionals - Students Subject: Re: cokin slide-in adapter for traditional lenses? Andrew What you are describing is a traditional lens board with a threaded hole in the center. The easiest way is to use a sacrificial Cokin filter with a carefully centered hole and a filter ring cemented into place. Of course, any suitable piece of material would do if the thickness was correct and the size the same. On Jan 28, 2013, at 11:59 PM, asharpe@xxxxxxxxxxxxxxxx wrote: > Hi folks, > > I wonder if anyone has ever invented a slide-in adapter for the cokin > series that had threads for traditional filters? > > I know that that problem is exactly what the filter system is trying > to solve, not needing separate sizes of filter for multiple lenses, > but the fact is, sometimes (usually?) traditional filters are of much > better quality than the cokin filters. Specifically, I'm thinking > about the cokin polarizers, which are unimpressive. I already have > some very good screw-in polarizers, but I'd like to use the cokin > system for my ND grads, and a screw-in polarizer on the lens with the > cokin system in front of it is clumsy at best, unusable at worst. > > It seems that a simple slide in card with an appropriately-sized hole > with threads would be very useful. So, does it exist? If not, perhaps > I can convince folks with a kickstarter project. > > Andrew >
