I have previously posted about using a shoulder strap to carry my camera with the 100-400mm lens fitted so that it is handy when wildlife appears. This has been successful and it has led to taking a lot more shots of things like birds in flight which I would otherwise have missed. The downside is that the camera and lens inevitably get banged against things - rocks, gates, etc. I have a neoprene lens coat on the lens which has done a pretty good job of protecting it, but the camera body has picked up some scratches - particularly on the corners. So I decided to try a Silicone Gel cover to provide a bit of protection to the camera body. After a bit of research, I bought one from Amazon designed specifically for my camera body.
Here it is on the camera:
and here it is in carrying position on the shoulder strap:
It is not particularly pretty, but it fits the body pretty well and certainly does the job of protecting the corners from bumps and scratches. The controls are all accessible and I haven't found it gets in the way of using the camera. So far, I would consider it a success.