Hello All, I have an interesting problem I'd like your help with.

I have an Elmo Super 103 super 8 camera. I used to shoot Kodachrome 40 in it, then Ektachrome 64, now Kodak is supplying Ektachrome 100D. My problem is that the Elmo's smallest aperture is f16 and the shutter is set at perhaps 1/30. In full sun Ektachrome 100D will overexpose by 2 stops, so I need an ND filter. Unfortunately the meter isn't ttl so this'll be a bit of a botch involving me screwing on the filer when the sunny 16 applies and unscrewing it at other times.

My question is, what ND filter to buy. Different brands seem to use different jargon. I think a B+W 2 stop ND filter is called "0.6" and the Hoya version is "ND4". Have I got this right? Obviously, as I'm projecting colour I need an actual neutral filter as no computer correction will take place. I also need to find the filter in 39mm. Should I go for the B+W? Are there any other choices to consider (Tiffen?, Heliopan?)? These things are costly, so I want to make sure I don't make a bad choice.