A technical challenge

I am now in an area of Kazakhstan called the 'Singing Dunes'. Walking on a steep slope of the dunes makes a very strange, bassoon-like deep sound under foot. It's quite unique. The lodging my photo tour group and I are staying in has a garden of beautiful flowers, and several hummingbird hawk-moths nectar from it. They move from flower to flower quickly, and it's a challenge to capture one that's sharp. In addition, their wing motion is extremely fast akin to the wings of a hummingbird. For this shot, I used manual exposure mode and 1/8000th of a second. I didn't have a flash setup so the top-end shutter speed was the best I could do. At first I selected f/11 and, with the ISO set to auto, that gave me 8000 ISO. These are the settings I used for this picture. I then tried f/16, and with the cloud cover I had that produced 25,600 ISO. I'm going to take more pictures later today and try f/22 simply because with my 100-400mm lens and a 1.4x teleconverter, the depth of field is so shallow -- given the fact that I'm shooting from only two feet away -- that I want to render the wings as sharp as possible. Using Neat Image software, I was able to eliminate the noise.