>>2838908It is a 600 f/4.
Just hold the mount. Bit of practice, and using it accurately is no problem. To get really quick with it, I confined myself to a crop body and 1.4x TC for a few weeks then went with full frame. After the crop factor and magnification were removed, it felt super easy and natural.
After 4 years I don't even notice the weight anymore, either... 8 or 10 hours of walking with it is a regular thing. Have used a tripod maybe 20 times when setting up blinds. But even then, I find it more convenient to just hold it.