My normal bird shooting, until recently, has been with 150-450mm on K-3 II (apsc crop sensor), and I have generally been getting nice images at 450mm handheld with camera shake reduction ON.
In the usual quest to get closer to some of the little blighters I recently added a 1.4x rear converter, so the max focal length is now 945mm (35mm equivalent).
I know this is getting a bit problematic for handheld shooting. I have previously tried using a but found it a hindrance much of the time when wandering about the bush. It is OK if I prop in one spot and wait for birds to appear, but it doesn't work for me when walking about.
I guess I'm not the only one in this situation, so I'm looking for advice on whether it's possible to get images shooting as I do, and how to do that, i.e. technique, camera settings, etc.