I painted those DIY snoots, I knew it and placed 2 of them either side and aimed at the smoke.
Used my 180 macro at a distance of 5' giving a DOF of about 3" shooting at f/18, 1/8sec/ ISO 400.
If I want a 12 inch field of view with more DOF...what mm lens might I use? I have 17mm to 300mm.