In your D40 box there is supposed to be a small black plastic piece that slides on the eyepiece, it for this exact purpose that it's included. The only thing is that with Pro. grade bodies, this curtain is built-into the camera body .. with lower-end bodies (D300 down-wards) it's an external piece that you slide on.
They are screw in. Have to remember to close the eyepiece too, or you get horrible purple blobs.
Gary.
I can only encourage you to get a 10 Stop. They are great fun.
I got the B+W one from Warehouse Express. Here's what Google throws up.
B+W 77mm ND-110 (3.0) SH Filter £152.39 - Warehouse Express
However, I am gobsmacked. I paid £62 delivered for the 77mm version last year. They've almost tripled in price !!!!
Just a thought guys - B & W isn't the only way to go....
Formatt (HiTech filters) do a 100mm slot in version for those who use Lee/HiTech/Cokin Z filter systems....
mine was delivered within 48 hours of ordering....total cost less than £50....
Haven't used it yet...hope to this weekend
Si
Can you let me know how you get on with this as I am interested in these as they are a fraction of the price. I used a screw in version in the past and found them a bit cumbersome and a slot in may be easier.
77mm filters are available at ABC for £57.25 inc delivery