It depends on what your goal is — to look very bright looking at the headlights or projection of the light far down the road.
The condition of your reflector will be important, the bulb type (filament position)has to match the reflector type too.
If the focus is good the light projected without the lens will be that of a spotlight— shining on a wall it should be a spot about the diameter of the headlights at 20 feet,
I have been using direct fit halogen bulbs from. Classicandvintagebulbs.com — I usually stop and talk with Anthony at Hershey
The original Ford bulbs have the high and low filaments close together and are designed to work with a single parabolic reflector, H4 bulbs have the filaments at different focal distances and the reflector for them usually has 2 slightly different parabola, one for each filament and a lens designed to work with them.
If the focus is not correct there will be a lot of scatter, the lights may look brighter standing near the front of the car but off to the side looking at them but the beam won’t go very far down the road.
It is important that the reflector is highly polished silver or better yet the modern aluminized reflector surface
The picture is showing proper focus without lens. Hardly any scatter, the light is only been projected in a straight beam.
