You're just about there. But hows-about we call the lights by their function so as to save on the confusion?(posted 8797 days ago)Your main light is [should be!] the light that casts the shadow on your subject, and sets the base exposure for everything else to work around. Your fill light adds light at a lower [hopefully!] level to soften the shadow created by the main, to the extent so as to achieve the desired effect that you want. With me so far?
Lets look at "light modifiers" for a moment. A light modifier is anything that you either stick to the head [bowl/dish reflector, beauty dish, softbox, 60/40 device, whatever] or stick in the lights path [gobo/flag, scrim]. Still hanging in there? Now, whichever method you use to "modify" your light quality, it will have a signature that may or may not support the effect you are after. A good example would be the use of a softbox to light a baby portrait [yuck!]. A softbox placed close to the subject would bring a light quality supportive of the subject, it would yield the baby in a nice, soft pool of light, making the little bugger appear all warm, cute, and cuddly. BUT, if you were to shoot that little rug rat with a 20K movie spot, placed at the same distance to the subject as the softbox was, besides getting a portrait that made Jr. look like David Hamiltons crispy offspring, it may be a little harsh too, but it would definitely yield a totally different "feel" to the resulting image. Kinda get the idea now? Just a little more, softboxes work because they broaden the area of the light, and create a large, diffused source. The closer to the subject that they are placed, the more apparent this soft effect is [to the point that they are placed equal to their long dimension]. Conversely, you could in theory, given a sufficiently powerful system, move a softbox far enough away from your subject to get it to replicate a focusing spot. Know what I mean?
This is a very broad subject, much beyond a single post; its more like a lifelong T&E exercise. One final point, the larger the light source the softer the look [generally] and that means the softer the shadow will be, given the same light is used [close softbox vs. far softbox, close 8 dish vs. far 8 dish, close 60/40 vs. far 60/40].
Technically, what all this is talking about is the edge effect of the demarcation area between the highlights and shadows, which is called the penumbra. A good definition of penumbra can be found in Photographing in the Studio, by Gary Kolb:
Penumbra: The transition area between light and shadow. The smaller the penumbra, the sharper the shadow appears, and the more contrasty is the light.
Still there?
So, not having used a 60/40, but thinking that I know how they work, I ass-u-me that it is a small pocket bounce device that is supposed to "soften" the flash by allowing you to bounce it into the 60/40. Is that correct? If, so you do not want to use it on your main light because it will diffuse the point light effect as compared to the bare head/tube. Now, this is all theoretical to this point, but if you truly want a focused spot effect, then any form of diffusion on your main would soften the penumbra, right? Still breathing? I usually would never advocate shooting a less than flawless model, with less than professional make up, etc. under direct light, but you did ask how to recreate the spot look. It may prove out that the 60/40 main, placed at a distance of say 8 feet would provide the effect youre after. But without the immediate feedback that roids give, it will be a very tedious wait for the film to see what happened. You will have to keep VERY specific notes, and make accurate measured diagrams of the lights relationship to the subject, etc. But again, I would put a naked strobe main above camera level, and may or may not use some sort of diffused fill at a 4:1 ratio [main light =4, fill =1, or main at f16, fill four stops less at f5.6] Oh, and BTW, there is a lot of dispute about lighting ratios, and their exact definition. But how I use them is to express the difference between lights as the example above. It works for me. Finally, the only reason that I would entertain the idea of using a fill would be because your main is probably too weak to keep the whole scene within the films dynamic range, but for a really dramatic look, definitely try one light only shots.
Im sure that I left a bunch of stuff out, but post whats still confusing, and Ill try to explain further. Welcome to the party, pal!