studio flash always harder than hotlights?

[pierods]

I was trying to determine whether hotlights are harder or softer than studio strobes.

I did a test with both kinds, unmodified, from a 45 degree angle (both azimuth and altitude) which seems to me the position that gives the harder light.

From my experiments, flashes are always harder than hotlights (also harder than fresnel).

Am I not testing right? I believed the opposite.

 

[Dan Quan]

To me the one marked "strobe" has a softer or more gradual edge transfer. But it also looks to have more fill, perhaps due to uncontrolled bounce within the room or environment.

 

[pierods]

I definitively have uncontrolled bounce. Maybe I don't master the jargon, but the strobe to me looks "harder".

 

[MattKing]

Whether a light is "harder" than another depends on how large the light source is. This is affected by the size of the source plus the effect of any reflecting surfaces or diffusing materials that influence the light path.

The studio flashes you are experimenting with are probably smaller sources than the hot lights you are comparing them with, at least when you take into account everything in the respective light paths.

 

[wildbill]

Many things make up the quality of light that a fixture emits. Size of the globe, type of filament, size of fresnel, etc. One type of fixture can be used to create the quality of light of another if it's in the right hands. "hotlights" is a pretty broad term since there open face, scoop, fresnel, open face with interchangeable lenses, and others. HMI fresnels have a different quality (besides color temp) of light than tungsten fresnels since the hmi doesn't have a filament which burns constantly.

 

[pierods]

Ok, all of this is true, but the strobe had a cone-type reflector in front of it, and the fresnel is an arri. Both were at 1 meter (1 yard) from subject.

As far as I understand, under these conditions they are both point light sources...

 

[Dan Quan]

But the Arri is focused while the strobe is funneled.

Harder and Softer can be somewhat unhelpful terms at times. Dean Collins spoke of edge transfer from light to dark and to my mind that is much more descriptive and clear to communicate or describe. Its more descriptive to say I need a harder or more abrupt edge transfer or a softer or more gradual edge transfer than to speak of just a harder or softer light.

 

[cowanw]

I agree with Dan. The cast shadows, where you can clearly see them, are softer with the strobe mostly seen at 10:30 o'clock just outside of the stem mark. i appreciate you are looking at texture, but a better assessment would be with a more substantial and even cast shadow, where the edge of the shadow is clearly seen.
Your background is matched but the orange is more exposed in the strobe picture.

 

[pierods]

I see guys. Thanks for explaining. Then I have two questions:

- a honeycomb filter in front of the strobe could possibly match a fresnel?
- do i need to paint my walls grey to avoid uncontrolled bounce or there are other (cheaper) ways to keep it in control?

 

[cowanw]

A honeycomb filter provides direction for the light, but doesn't concentrate it (or diffuse it) as does a Fresnel.

 

[Dan Quan]

I see guys. Thanks for explaining. Then I have two questions:

- a honeycomb filter in front of the strobe could possibly match a fresnel?
- do i need to paint my walls grey to avoid uncontrolled bounce or there are other (cheaper) ways to keep it in control?

No, a fresnel focuses or defocuses the beam of light. A honeycomb adds a degree of control of the spill.

Hang Duvateen or Comando cloth as needed. The 16oz prevents light passthrough, for use over a window or in front of a source.
http://www.rosebrand.com/shop/results.aspx?keywords=duvateen

edit: http://www.rosebrand.com/subcategory151/fabric-by-type-commando-cloth-duvetyn.aspx

 

[pierods]

No, a fresnel focuses or defocuses the beam of light. A honeycomb adds a degree of control of the spill.

Hang Duvateen or Comando cloth as needed. The 16oz prevents light passthrough, for use over a window or in front of a source.
http://www.rosebrand.com/shop/results.aspx?keywords=duvateen

edit: http://www.rosebrand.com/subcategory151/fabric-by-type-commando-cloth-duvetyn.aspx

fantastic, thanks!

so a focused light will be always harder than a non focused light, I must understand?

 

[Dan Quan]

Not necessarily, the sun is not focused but can provide a shadow with a very distinct or hard edge transfer because it's so far away and relatively small. But, with artificial light sources a focused light will generally provide a sharper edge transfer than a non-focused light. And the edge transfer will be more abrupt the closer the occlusion is to the shadow, and become more diffuse as the distance between the occlusion and shadow increase. This is where a focused, or smaller source at a greater distance can really be appreciated.


edit: With most light sources (I am not familiar with ALL light sources) the edge transfer will be more abrupt the closer the occlusion is to the shadow, and become more diffuse as the distance between the occlusion and shadow increase. This is where a focused, or smaller source at a greater distance can really be appreciated.