We mentioned the Rokinon 8mm f2.8 several times on the blog as being a great lens for its price. One thing that is kinda hard to do with this lens is use filters. This is both because the curvature of the lens extends beyond the filter thread and also because of the shape of the petals of the built in lens hood.
This makes it practically impossible to place an ND filter on such lens. The folks at CheesyCam just shared a sweet hack using a Rosco ND gel and some blue tack. The trick is to place the gel at the back of the lens rather than in the front of the lens as we usually do. For ND CheesyCam uses the 3404 gel from the Rosco cinegel sample book, which cuts 3 stops off, and placed it using some blue tack.
Even zoomed in at 400% I was actually quite surprised that the gel almost did not introduce any softness.