The Sigma 150-600 Sport lens is a beast at 2.8kg. This makes it very hard to handle handheld and indeed most people will use this lens on a monopod or tripod. I'm more of a run and gun photographer though so I took matters into my own hands, literally. Introducing the Sigma 150-600 Sport Comfort Handle. Now built for humans, you know the things with fingers.
This thing is a pretty large part which would be expensive to print completely solid. If you want to do that however you can buy one on Shapeways here.
To make a small production run I decided to use a cheap FDM print with low infill to make a mold. This part would not be strong enough to be functional but does a great job of being a positive of the shape. The mold was constructed out of silicone rubber and then a grip was cast with fiberglass reinforced epoxy. The resulting part is EXTREMELY strong and after a coat of paint looks almost exactly like the renders.