In samatha practice, there is samma samadhi, right samadhi. Where right Samadhi is concerned, the practice is the same as vipassana.
In samatha also you don’t focus. You very gently and patiently reapply your attention on the object, over and over and over again. You’re only placing your attention on the object; you’re not placing your attention and pressing it into the object. Samatha is simply placing your attention on the object, over and over and over again until it becomes more powerful.
But now yogis have a misconception that to make the concentration stronger, they have to press into the object; but there is no need.
It’s a simple placing, over and over again.
If you’re doing right samatha practice, you don’t feel heavy; you feel light and clear, samma samadhi. If you are feeling heavy, it is already wrong samadhi.
[Yogi’s note: You don’t focus in samatha practice – you’re gently and patiently reapplying your attention on the object, over and over and over again until it becomes more powerful]