How do you use a penlight in photography?

Question: How do you use a penlight in photography!?

in detail, please!?
and also, do you HAVE to use a penlight, or can you use a flash light source!?Www@QuestionHome@Com

Best Answer - Chosen by Asker:

The larger the beam, the wider the light path!.

Coverage wise:

Penlight would be like a pencil
Flashlight (or torch) would be like a broad brush
Photo lamp would be like a commercial paint sprayerWww@QuestionHome@Com

If you mean to take a naturally lit dark subject with a section highlighted by a penlight beam you must expose for the natural light and ignore the beams input, this will give a very moody scene with contrasty highlighted section!.
Try it!Www@QuestionHome@Com