Grid Spot vs. Snoot vs. Barn Doors

Since I don't have all three of these, I was wondering if anyone here knows? How they differ in regards to quality of light? I realize that they could all shape the edges of the light differently square vs. round and so on. I also know that passing the light through some sort of diffusion material will alter things again so we'll leave diffusion off the table.

What I'm interested in, is with all things being equal, how are they different between themselves? For instance if you have a 10 degree grid over a light and compare it to the same light source with barn doors and also to a snoot, all set to cover the same 10 degree area of interest. Do the edges feather softer or harder? Is there any noticeable differences at the center of spot? Does the grid drop exposure level more than the others?
Also are there any other things between these modifiers that should be considered regarding their differences in quality of light?

Mike

Here's some light reading for you.
Plenty of good info amongst a mild clash of egos.
https://photography-on-the.net/forum/showthre​ad.php?t=251549

Thanks for the link.

Basically, it goes like this:

Either a snoot or barn doors will give you hard edges, while the snoot will give you a single shape that stays constant, but the barn doors give you the ability to change the shape (they also, however, make it always rectangular, so you can forget about throwing a round background light into a scene if you use the barn doors).

The grid spot will give you a circle with really soft faded edges, like a round snoot, but without the hardly defined edges. I work with small flashes, so my gear isn't nearly as expensive (I put most of my light mods together myself), but I make sure to have a snoot and a grid-spot around all the time, so I can constrain light with either a hard or a soft-edged look, however I need it.

I am a big fan of using barn doors but I can also say that it takes some time to understand how to make them work for you. A common misundestanding is that the doors will create hard lines. Not true. Barn doors can create smooth transitions and are great tools for shaping light. Grid spots are also great for collimating light.

Of all the shaping tools I find grid spots and barn doors to be the most useful. I also know many people that use snoots and they do have their place but I just don't find them to be as versatile.

How do you get soft edges off barn doors, Robert? If I ever end up with studio lights, I might have to look into them.

bieber wrote in post #4051127
How do you get soft edges off barn doors, Robert? If I ever end up with studio lights, I might have to look into them.

At the risk of stepping on Robert's answer, a better question might be, "How do you get hard edges with barn doors?" With the doors as close to the circular flash tube as they are, there simply is no hard shadow line. With the small, point source halogen type of modeling light, it is possible to get a fairly hard line and I imagine it is possible with hot lights. The small tube in a portable, hotshoe flash will also produce a fairly hard line, but a circular tube like those found in studio strobes is just too wide to produce a sharp shadow line from that close.

bieber wrote in post #4051127
How do you get soft edges off barn doors, Robert? If I ever end up with studio lights, I might have to look into them.

Hi Robert. Jim is correct. Unless you have the light within about 12 inches of the subject or background and there is great contrast you're never going to have a hard edge.

If you create a 1" opening with a set of barn doors and fire the strobe directly at a black background from 2 or 3 feet away you'll see that you don't get an even slit of light with hard lines. The light still spreads and without any diffusion there will be more concentrated light at the center. It will be collimated to an extent but not like you might think.

Robert and all, I know what 'collimating light' means and I understand the process. I even looked it up on wikipedia to make sure I was correct. But, what is the effect of this on the quality of light?

Atomic79 wrote in post #4058346
Robert and all, I know what 'collimating light' means and I understand the process. I even looked it up on wikipedia to make sure I was correct. But, what is the effect of this on the quality of light?

Barn door does not apprecialbly alter the quality of light, it merely masks down the amount of area covered by the light.

Imagine a roller shade in sunlight...the light coming thru is hard, regardless if the shade is more open or the shade is more closed.

Now imaging the same shade in overcast...the light coming thru is soft, regardless if the shade is more open or the shade is more closed.

What is affected in both cases is the amount of the room which is lighted by the hard/soft light, the 'quality' is unchanged.

Atomic, keep in mind that there's really no such thing as "good" or "bad" light, only "appropriate" and "inappropriate." In a glamour portrait, I'd probably never even consider using hard light; for the swim team headshots I'll be doing tomorrow, I'm gonna be bringing a snoot along for some nice, hard, narrow throw. Don't think of soft as good and hard as bad, just think of them as hard and soft, and use each whenever you feel it would look best (remember, we are, after all, artists )