Try this DIY Neutral Density Filter for Long Exposure Photos
Make a DIY Filter Adapter for Your Lens Using a Large Sponge | The Dream Within Pictures
How to Make a DIY ND Filter (Cheap Neutral Density Filter) - YouTube
DIY ND Filter: Tutorial for Beginners
DIY - Homemade ND filter using a piece of welding glass. Then using the RAW file and Photoshop, adjust the white balance to g… | Glass, Metal working, Diy homemade