Lighting and Umbrellas

[Camdixon]

Hey DPS.

I have been reading about using off camera lighting to really add to a picture/portrait.
As far as umbrellas go I have seen 32" and 45". Other than the obvious different in size why would it matter? Is a bigger one better or a smaller one? I'm going to buy the shoot-through kind, just thought I would ask some pros what the difference is.

[topherlin]

from my understanding, you're going to want to use the larger umbrella whenever you're looking for more diffusion and the smaller one when you're looking for less.

[Mike367]

Not a pro, but here's my take:

A larger umbrella essentially means a larger light source. ( the entire umbrella is the light source) The softness of the light is proportional to the relative size of the light. "Relative" means relative to the subject. A light closer to the subject is relatively bigger. A large light very far away (like the sun) is still very hard. By "soft" or "hard" I mean the transition between light and shadow, a soft light has a gradual transition, a hard light has an abrupt transition.

At the same distance, a larger umbrella will be softer. Larger umbrellas bump the ceiling more (indoors) and catch more wind (outdoors).

[carl yeomans]

Strobist: Lighting 101 <--work your way through this and then ask your questions.

Carl.

[BigFuzzy]

Originally Posted by Mike367

Not a pro, but here's my take:

A larger umbrella essentially means a larger light source. ( the entire umbrella is the light source) The softness of the light is proportional to the relative size of the light. "Relative" means relative to the subject. A light closer to the subject is relatively bigger. A large light very far away (like the sun) is still very hard. By "soft" or "hard" I mean the transition between light and shadow, a soft light has a gradual transition, a hard light has an abrupt transition.

At the same distance, a larger umbrella will be softer. Larger umbrellas bump the ceiling more (indoors) and catch more wind (outdoors).

Well answered. Exactly this.
And yeah, check out Strobist if you're interested in this stuff.

[Camdixon]

I have been reading Strobist actually, which has brought me to actually try additional off camera lighting to add something to the photos. Thus far, Strobist has been extremely helpful. I am going to try their recommended light kit, but it also mentioned I could go with umbrellas of those sizes. As far as I could tell it didn't give me an explanation of the differences.

Just to make sure I'm clear on this, the larger umbrella will provide "softer" light set at the same distance away than the smaller one. Also, it will act as a "larger" light source on the photo subject. Does this mean if I use the bigger umbrella then I will need to set the flash to a higher level to produce the same amount of light as a smaller one would? What I'm asking is I know the larger one will be seen as a bigger source, but since it is bigger does that mean I will need to turn up the flash (or will it only make it a "harder" lightsource if I turn up the flash level)?

[zona5101]

Originally Posted by Camdixon

Just to make sure I'm clear on this, the larger umbrella will provide "softer" light set at the same distance away than the smaller one. Also, it will act as a "larger" light source on the photo subject.

Yes, softer, bigger, more wrap around lighting producing softer transitions to shadows, smoother reflections, less revealing of surface texture...

Does this mean if I use the bigger umbrella then I will need to set the flash to a higher level to produce the same amount of light as a smaller one would? What I'm asking is I know the larger one will be seen as a bigger source, but since it is bigger does that mean I will need to turn up the flash (or will it only make it a "harder" lightsource if I turn up the flash level)?

Generally yes. The larger the diffuser the more power it will take to illuminate it's surface evenly (generally on an umbrella it is because you have to have the umbrella farther away from the flash to get full illumination. Same goes for softboxes but usually the inner baffles are what spreads the light out evenly rather than moving the surface closer or farther like you would for an umbrella.)

Also shoot-through unbrella will suck more power than a silver refletive umbrella. But they have different effects on the subject so that trade off is part of your artistic choice when deciding on how to light a subject.

[Camdixon]

Thanks a ton guys! Helped me out.