Funny Story....
150€ Filter and a Filter holder out of the 3d printer....
On the first view a great combination...:D
So my first long exposure test was from my roof window.
To expand my exposure I used Kodak Gel Filter and my new Filter holder with an 0,9 ND Grad.
Unfortunately the Filter drops out of the holder and has land in our roof gutter without damage.... Hey I love safety glass :D
The bad is the that our gutter is 10m height and so unreachable without a ladder....
So easiest solutions was to drop the Filter out of the gutter and hope the best ;D
Fortunately the glass is really stable and it's not broken :)
Now my question: how do you use 150mm grad Filters on the Canon Lens?
I have to improve the holder with more cellular rubber....