Flash Question

[dch]

Originally Posted by Brooks

Hard light, from small light sources such as the sun or an on-camera flash, is unable to "wrap around" the subject because the light rays are mostly parallel and coming from one direction.

No, that's because light does not bend.

You can take that same direct flash that makes harsh shadows on a person and then photograph a lady bug up close for example, and you will have "soft light" -- same exact light source. Why? Because the light source is LARGER than the subject and is able to wrap around it.

Sticking a diffuser on the end of your flash does NOT make softer light -- it just scatters the light -- which if INDOORS will make a larger light source because it is bouncing off all the walls and ceiling. Outdoors, it's just scattering the light out into the atmosphere, and the same amount of light (after you crank up the power on the flash to make up for all the wasted light going everywhere) will fall on your subject and look the exact same.

I hope I am explaining this well enough for you to begin to understand.

[Brooks]

Originally Posted by dch

No, that's because light does not bend.

You can take that same direct flash that makes harsh shadows on a person and then photograph a lady bug up close for example, and you will have "soft light" -- same exact light source. Why? Because the light source is LARGER than the subject and is able to wrap around it.


I hope I am explaining this well enough for you to begin to understand.

Actually a prism is able to bend light , and even separate white light into the three primary colors of light, red, blue and green. But that's not what is being discussed here.

The reason a direct flash produces softer light when used closer to a macro subject is because it's bigger which allows light from many different angles to hit the subject.

And that same light is harder when used at a distance because the only light rays reaching the subject are coming from a single direction.

The hard and soft qualities of light are dependant on whether the light comes from a single direction or from multiple directions. The way you get light from a single light source to strike the subject from many directions is to have a light source that's larger rather than smaller, or closer rather than farther away.

The fact of the matter is that a soft light strikes the subject from many random directions while a hard light strikes the subject from a single direction.

I hope I'm explaining this well enough for you to begin to understand.

[Brooks]

Here's a poorly drawn illustration which may clear up any confusion you might have.

Notice how the light rays under the soft light source strike the subject from an infinite number of angles. That's what causes the light to "wrap around " the subject. The light doesn't bend around the subject it comes from so many directions it more easily hits other areas on and around the subject. The light striking the subject from those infinite number angles and directions is what makes this light a "soft" light.

Notice how the light rays from the hard light source strike the subject from a very small number of directions and angles. Imagine that light source to be even smaller and farther from the subject. Then the only rays striking the subject would be parallel with very few light rays from any other appreciable angle. This organized, parallel arrangement of light rays is what makes this light a "hard" light.

[dch]

See, you are confirming everything I have said -- Each ray of light itself, is neither HARD or SOFT. It's the combination. And the only way you can have rays of light coming in from the sides, etc. like your diagram above, is for it to be LARGER than the subject. Sticking a diffuser on the end of a flash, like a lightsphere or omni-bounce will not change how the light hits your subject. It would hit your subject just like your Hard Light example, however other rays of light would be spreading out in all other directions -- which, will not ever reach your subject (unless of course you are indoors and those other rays will bounce off of walls, etc.).

[PetersenPhotography]

Originally Posted by Brooks

Here's a poorly drawn illustration which may clear up any confusion you might have.

Notice how the light rays under the soft light source strike the subject from an infinite number of angles. That's what causes the light to "wrap around " the subject. The light doesn't bend around the subject it comes from so many directions it more easily hits other areas on and around the subject. The light striking the subject from those infinite number angles and directions is what makes this light a "soft" light.

Notice how the light rays from the hard light source strike the subject from a very small number of directions and angles. Imagine that light source to be even smaller and farther from the subject. Then the only rays striking the subject would be parallel with very few light rays from any other appreciable angle. This organized, parallel arrangement of light rays is what makes this light a "hard" light.

Originally Posted by dch

See, you are confirming everything I have said -- Each ray of light itself, is neither HARD or SOFT. It's the combination. And the only way you can have rays of light coming in from the sides, etc. like your diagram above, is for it to be LARGER than the subject. Sticking a diffuser on the end of a flash, like a lightsphere or omni-bounce will not change how the light hits your subject. It would hit your subject just like your Hard Light example, however other rays of light would be spreading out in all other directions -- which, will not ever reach your subject (unless of course you are indoors and those other rays will bounce off of walls, etc.).

Ok - it's time to end the contest. The fact is that you are both right. Photons travel in a wave-like pattern on a straight trajectory. Dch is right about the PHYSICS. There is no "hard" or "soft" about light as we discuss light's physical properties.

Brooks is right that light is hard or soft as we discuss AESTHETICS. In that sense, "hard light" is that which is not diffused and travels, uninterrupted, from the source to the subject. "Soft light" has been reflected in some way so that the single source now strikes the subject from multiple angles. Brooks is right that light's aesthetic qualities can be modified to be "hard" or "soft" - our own subjective terminology to describe how light is (or is not) modified.

[Montec]

Originally Posted by PetersenPhotography

Ok - it's time to end the contest. The fact is that you are both right. Photons travel in a wave-like pattern on a straight trajectory. Dch is right about the PHYSICS. There is no "hard" or "soft" about light as we discuss light's physical properties.

Jacco is right that light is hard or soft as we discuss AESTHETICS. In that sense, "hard light" is that which is not diffused and travels, uninterrupted, from the source to the subject. "Soft light" has been reflected in some way so that the single source now strikes the subject from multiple angles. Jacco is right that light's aesthetic qualities can be modified to be "hard" or "soft" - our own subjective terminology to describe how light is (or is not) modified.

Whew...glad to hear But just to reiterate, a photo taken outdoors with a LightSphere on my SB800 has softer shadows than if I use direct flash. You cannot argue with the results.

Thanks to all who replied to my original question.

[Brooks]

Originally Posted by PetersenPhotography

Jacco is right that light is hard or soft as we discuss AESTHETICS. In that sense, "hard light" is that which is not diffused and travels, uninterrupted, from the source to the subject. "Soft light" has been reflected in some way so that the single source now strikes the subject from multiple angles. Jacco is right that light's aesthetic qualities can be modified to be "hard" or "soft" - our own subjective terminology to describe how light is (or is not) modified.

Jacco ??

[PetersenPhotography]

Sorry - I wrote that in a little bit of a hurry (on vacation in FL with the in-laws). I've corrected for the names in my post. Sorry, Brooks!! Don't hate me for it.

[dch]

Originally Posted by Montec

Whew...glad to hear But just to reiterate, a photo taken outdoors with a LightSphere on my SB800 has softer shadows than if I use direct flash. You cannot argue with the results.

Uh, how about showing us the results of two properly exposed shots -- one with and one without LS.

[Ed Shapiro]

As we all know the word "Photography" means painting or drawing with light- lighting is the very essence of the craft. With that in mind we should all appreciate how important the discussion of the behavior and physics of light and the resulting aesthetics effects. The word "Diffusion" means breaking up of any given beam of light thus disbursing or scattering the rays in many different ways depending on the methodologies or equipment utilized. Some methods are very subtle and other are are very distinct and easily noticed.

The basic physical rules hold true in most cases but there are some subtleties and nuances that are "between the lines" so to speak. In the case of small diffusion devices that attached to portable and shoe-mount flash units there are many myths and truths. Yes, if we attach one of theses devices to an on-camera flash we do not increase the size of the effective light pattern enough to make a big difference- it is still basically a point light source when compared to a big umbrella or a soft box and it is essentially a flat lighting so it is not gonna magically turn a flat lighted harshly lighted image into a beautiful portrait. Many of theses devices will, however, soften the light just a touch making it a better fill light source in a multiple lighting setup. The fact that the device absorbs some light, a more dramatic ratio can be achieved when the power can not be easily adjusted or the fill light, being attached to the camera, can not be moved further away from the subject.

Some of theses devices will work more effectively in a smaller light colored room,especially the semi-spherical and bounce card models. What happens is the amount of "unseen secondary" bounce light reflects off the ceilings and wall and soften the image just a bit more. In a large room, a vast venue such as a church or our of doors theses devices have little or no effect- the proverbial "flatulence in a windstorm" (please note the polite medical terminology).

It is also true that light sources that are relatively larger and/or closer to the subject ten to "wrap around" better but the degree of that effect is also dependent on reflectivity of the surroundings- thus the use of reflectors and later movement of the lights as well as feathering. Although an umbrella is nothing more that a big parabolic reflector it will wrap around much more effectively that a smaller metallic parabolic reflector. When using say 16" parabolics in a portraiture set up, oftentimes more than one main light is needed to get the wrap around effect.

Sooo..besides the size and configuration of a diffusion device, the surroundings that it is used in, the degree of unseen secondary light, and the position of the lighting equipment also influence the final effect.

Isn't lighting cool stuff? I hope this helps! Ed

[E-Man]

A very nice write-up, Ed. Thank you! This really helps the newer guys like me learn!