Understanding Lighting - Strobist

[KevinStecyk]

Originally Posted by David_Buzzard

For doing outside portraits with flash, you really want to find locations that without flash, the main subject would be silliouted against the background. Under trees or covered patios are prime spots. For big shoots, like Vanity Fair, they bring big canopies to set up on location to keep the ambient light off the subject, and then light the subject with strobe.

To sum up, find a covered area that is darker than your background to put your subject in, set up your light, or lights, so that the subject is properly lit, and then adjust the shutter speed until the background is properly exposed.

If you look at the archive on my blog, the entries 'Falconer', 'Stacy Kohut on the Four Cross', and 'An Inconvenient Truth', are all shot in this style. in a lot of them, if you look at the ground you can see the shade from the trees I poised them under.

David Buzzard's Technical Blog

David, I've looked at your great shots. Again, you're putting your subjects in the shade so that you can light them up with your lights?

If they were in the harsh sunlight, then the photos are not very good. That I understand. So you are placing them into the shade so you can create your own lighting environment, where the lighting is more even?

And in the Inconvenient Truth, you wanted Earth and the presenter to stand out.

Again, thank you.

[David_Buzzard]

If you're using flash, you want the subject to have much less ambient light than the background. With the "Inconvenient Truth" the room was totally dark except for the slide on the screen. I set the exposure so that the shot on the screen would be properly exposed, and then hit the subject with the flash to light him.

If the light is really strong, and you can't find any shade (like the "Chainsaw Action" shot), move around so that the subject is totally backlit, and then light the subject from in front. Since there's isn't any sunlight on the front of the subject at all, you can light them with flash. Keep in mind you need lots of power to do this. When I did the 'Chainsaw Action' I took the diffuser off the flash, and it was only about 4 feet from the subject, and was still firing at full power.

David Buzzard's Technical Blog

[KevinStecyk]

Originally Posted by David_Buzzard

If you're using flash, you want the subject to have much less ambient light than the background. With the "Inconvenient Truth" the room was totally dark except for the slide on the screen. I set the exposure so that the shot on the screen would be properly exposed, and then hit the subject with the flash to light him.

If the light is really strong, and you can't find any shade (like the "Chainsaw Action" shot), move around so that the subject is totally backlit, and then light the subject from in front. Since there's isn't any sunlight on the front of the subject at all, you can light them with flash. Keep in mind you need lots of power to do this. When I did the 'Chainsaw Action' I took the diffuser off the flash, and it was only about 4 feet from the subject, and was still firing at full power.

David Buzzard's Technical Blog

Thank you David for all your help!

[KevinStecyk]

Originally Posted by David_Buzzard

If the ambient light is the same on the subject on the foreground and background, then as you increase the shutter speed, the ambient light, the flash will have less affect on the subjects in the foreground. If the ambient light is less in the foreground, then the flash exposure will stay the same, while the ambient light in the background gets lighter.

I was just rereading your post again.

ambient light (situation 1)

• foreground = background
• flash has little effect because it is overpowered by the natural sun
• increase shutter speed (decrease time)
  • foreground darkens but is somewhat mitigate by flash; background gets darker?

ambient light (situation 2)

• foreground darker than background
• flash has strong effect because it is not competing with the natural sun
• increase shutter speed (decrease time)
  • foreground unaffected by flash; background gets darker?

Originally Posted by David_Buzzard

For doing outside portraits with flash, you really want to find locations that without flash, the main subject would be silliouted against the background. Under trees or covered patios are prime spots. For big shoots, like Vanity Fair, they bring big canopies to set up on location to keep the ambient light off the subject, and then light the subject with strobe.

To sum up, find a covered area that is darker than your background to put your subject in, set up your light, or lights, so that the subject is properly lit, and then adjust the shutter speed until the background is properly exposed.

If you look at the archive on my blog, the entries 'Falconer', 'Stacy Kohut on the Four Cross', and 'An Inconvenient Truth', are all shot in this style. in a lot of them, if you look at the ground you can see the shade from the trees I poised them under.

David Buzzard's Technical Blog

If I wanted the background one or two stops darker than the foreground, then does it make much difference whether I am in shade or not?

If I am in shade, I use my max sync speed of 1/250 sec and use my off camera strobes with my camera set to the smallest aperture I can get away with. The background will be whatever it is. If I want it brighter, I can add more time (decrease my shutter speed). If I want it darker, I am out of luck (assuming full power strobes, strobes placed near the subject, camera set to smallest aperture for proper subject exposure).

If I am in the sun, isn't my result the same? By using a small aperture and 1/250 second, I have now allowed the strobes to play a more prominent role in lighting the subject. (If I recall correctly, typically outdoors is ƒ7.1 - 8 at 1/250 sec at iso 100?).

Let's say for example, I was able to use iso 100, ƒ16, and 1/250 in the shade (not sure if this is realistic with two Canon off camera strobes). Then I should have a 2 ƒ stop difference for the background (ƒ16 versus ƒ8 for ambient)? If I shot this same scene in the sun, would my results be materially different?

I am not doubting your advice. Rather, I think I might be missing something conceptually. So I'd like to clear that up sooner rather than later.

I am going to be practicing this coming Wednesday (assuming the weather cooperates). I've got my off camera strobes and Pocket Wizards.

[ChrisPerry]

When using flash the aperture controls the amount of light the flash contributes to the image, not the shutter speed. Shutter speed controls the ambient light.

The challenge when working outside in / around the sun is that you often have to have shutter speeds in excess of X Sync (1/250 for most cameras) to get a proper exposure if you want fairly wide apertures.

My wedding last week I got this all to work fine - I put the couple in the shade, an ND filter on my lens, and one camera and off camera flash (speedlights via PW). Great me thinks I got this! Did a senior and it worked well too.
Then yesterday's wedding comes along. Knowing I'll have to do groups I bring my studio light (300ws vs 50 to 80ws for speedlights). I use it for church formals all the time with no problems. We move into the shade with the antebellum mansion in the BG (in full sun) and I can't get enough flash output no way no how on the folks up front..even wiht all teh diffuser material removed from a 2x2 softbox and the power all the way up....so I remove the ND, up the ISO..I eventually get a workable solution but it's not what I had planned or thought was gonna work. Argh. Just when I thought I knew what I was doing it all failed on me.


I'll have to go out in the yard and try to recreate the conditions and see why a studio light didn't behave as a speedlight ... light is light, isn't it?

[KevinStecyk]

Originally Posted by ChrisPerry

When using flash the aperture controls the amount of light the flash contributes to the image, not the shutter speed. Shutter speed controls the ambient light.

The challenge when working outside in / around the sun is that you often have to have shutter speeds in excess of X Sync (1/250 for most cameras) to get a proper exposure if you want fairly wide apertures.

My question, though, is what is the difference between shade and open if I am blasting at close range with two or three strobes at maximum strength?

I can't use large apertures because my sync speed is 1/250. So that drives me to using smaller apertures, say ƒ11 to ƒ22.

In normal daylight at iso 100, ƒ16 and 1/250 yields an underexposed photograph, which is what I want for my background. So if I use this setting in shade shooting out into the sunlight or in sunlight shooting out into the sunlight, how do these two situations differ?

[KevinStecyk]

For those interested, the Strobist has an article with seven (7) strobes being used to fire into daylight. That's too much for me, but I thought it might interest others.

[Pro Photo Store]

Visit the B&H Pro Photo Store for the best Gear Prices and regular specials!

Brilliant Color for any Digital SLR
White Balance Cap
The Pros Agree on ColorRight
What People Are Saying