Focusing a Schneider 35mm/5.6 with center filter in weak indoor light on the ground glass can be rather challenging.
The trick I'm using today is to focus before framing: aim the camera/lens directly towards the object I want to focus at so I get to focus in the direct center of the lens => no tilting of the loupe required and there's no sideways movement from the focus breathing so it becomes considerably easier. If there's only low contrast objects where I want to focus I can put some high contrast object there as focusing target, like a small bright LED clock (bright light and sharp shapes). With this method you cannot fail even in these poor conditions
However, it would be cool if one could instead of that LED clock as focus target use a laser pointer (so you don't need to walk into the scene), which I could mount in an arm in the cold shoe on the camera and aim at the place I want to focus at. For this to work the laser must be bright enough, and I think it should have some shape, such as a crosshair, as a point is more difficult to focus-peak than a shape. I've tried to focus on the laser point from a Leica Disto D5, and it sort of works, but the point is not too easy to peak at, a well-defined sharp shape would be better.
Has anyone tried this method and have a recommendation for laser pointer product?