Do I need more power? Question about a specific situation.

I'm up for a job shooting a roller derby team, depending on if they can afford my measly quote.

For singles photos I want to do the photos outside and I'm thinking my setup is going to be something like this:

I want two lights with strip boxes at 45 degrees behind the subject to the left and right to give a nice strong highlight. I'm going to have a hairlight coming from behind the subject. The main light is going to be a beauty dish or a silver umbrella that's closed a bit to focus the light.

I have a 1200w/s Speedotron pack and a 400w/s pack. I'm wondering if this is going to be enough to give me a slightly darker sky? I have a 6 stop ND and I'm going to be purchasing a 3 stop ND shortly. Last time I shot with the 400w/s pack with one light in a beauty dish with the 6 stop, I was still having problems overpowering the sun.

I figure I'll have the 400w/s pack with one head providing the hair light and adjust the power as necessary. The 1200w/s pack will let me run one light at 600w/s and two at 300w/s. Does anyone have experience that tells them that this will be enough to darken a sunny sky with the main light, but provide a good highlight with the strip boxes if they're only running at 300w/s each, or will I need to possibly purchase another pack?

I'm going to test this out and try and get a good setup in the next couple of weeks. This shoot won't be until the weekend of February 19-21. I'm completely unsure as to what the weather is going to look like at that point, so I have to count on being able to overpower the sun if needed.

Just sitting here at work and wondering. If anyone has any experiences, ideas, suggestions, etc...I'd like to hear them.

Do you have a lightmeter? If yes it is so much easier to know what kind of exposure readings you get at the subject distance you envision for this shoot using the modifiers that you want. Use sunny 16 rule to get your ambient exposure. Then compare what your lights can do. You know how many stops your lights are above the ambient. You need ambient knocked down say 2-3 stops depending on how dark you want.

Even if you don't have a meter, just take some test shot and you know if you over power sun or not. Faster than anyone else telling you if you can do it or not, isn't it. We don't have your gear and strobe power readings don't mean much, IMHO.

bobbyz wrote in post #11712033
We don't have your gear and strobe power readings don't mean much, IMHO.

Unless some one has experience with a similar setup

I side with bobbyz...take a reading at 10' with the 1200w/s pack with one head at 600w/s into whatever modifier you plan to use. Anything else is still a guess, since you would have no idea if my modifier was more efficient or less efficient than yours!

If the reading is not higher by 1EV than comparable daylight Sunny 16 expectation (f/16 at ISO100), no 'darkening of the sky' will take place. If you can get f/16 reading, since you can set shutter to 1/200 and still capture all the flash output while darkening the sky, you could accomplish same in real situation.

When using a modifier such as a softbox or umbrella, you'll need at least 1200ws of power to overpower the "noon" sun (assuming you're doing full length shots of the subject and your light is 8' to 10' away...), with a beauty dish - about 800ws.

The Loft Studios wrote in post #11713941
When using a modifier such as a softbox or umbrella, you'll need at least 1200ws of power to overpower the "noon" sun (assuming you're doing full length shots of the subject and your light is 8' to 10' away...), with a beauty dish - about 800ws.

Different flashes have different efficiencies, but the above statement seems pretty consistent with my findings...

Dynalite M500 (500 w-s full pwr) would yield f/16 at 4' or GN64 -- in a 24"x36" softbox. The softbox used was losing about -1.25EV So using this setup I could overpower the sun only out to 4' light to subject.

I would add to what has been said that using HyperSync or a camera which will let you sync fastser than typical 1/200 max sync speed also helps when overpowering the sun. I can easily do 1/500 on my 1dmk2 with mini/flex and AB800. So instead of 1/100 if I can do 1/500 I gained more than 2 stops, isn't it.

Here is one with AB1600 (640ws) at ISO50, 1/200, using AB beauty dish. Don't remember the exact power but pretty close to full.

Wilt wrote in post #11714080
Different flashes have different efficiencies, but the above statement seems pretty consistent with my findings...

Dynalite M500 (500 w-s full pwr) would yield f/16 at 4' or GN64 -- in a 24"x36" softbox. The softbox used was losing about -1.25EV So using this setup I could overpower the sun only out to 4' light to subject.

They're going to be single person shots, so I can pull the lights in closer, what I'm really worried about is if the two strip boxes at 300w/s are going to be enough to provide a rim light? I guess that's what you would call it.

I need another 1200w/s pack I think.

wow....

Alright...I get can get the ambient to be pretty dark with my b800, shot through a beauty dish, on full power. You'll want to get your f/stop's up there, since you can only have 1/200th. ND filters aren't going to help one bit since they knock down the flash exposure as well.

So, you should be fine with the 400w head, even more so with the 1200w. with a b1600 on FULL, you should be able to get f/16 pretty easily....so with f/16 and 1/200th, that can usually knock down the ambient pretty well.

the 300ws for the rims will be fine, just have them on full power as well.

Use rim lights without modifier if you need more juice from them.

GenuineRolla wrote in post #11717297
wow....

Alright...I get can get the ambient to be pretty dark with my b800, shot through a beauty dish, on full power. You'll want to get your f/stop's up there, since you can only have 1/200th. ND filters aren't going to help one bit since they knock down the flash exposure as well.

So, you should be fine with the 400w head, even more so with the 1200w. with a b1600 on FULL, you should be able to get f/16 pretty easily....so with f/16 and 1/200th, that can usually knock down the ambient pretty well.

the 300ws for the rims will be fine, just have them on full power as well.

I used the 400w/s pack with a Kacey beauty dish previously. Don't mind the tint, I believe it's from the ND. This was with the 6 stop B+W I have.

IMAGE LINK: http://www.flickr.com/​photos/cokronk/5171206​736/

bobbyz wrote in post #11717516
Use rim lights without modifier if you need more juice from them.

What can I do to get a similar spread/control as a strip box. Barn doors?

Village_Idiot wrote in post #11717110
They're going to be single person shots, so I can pull the lights in closer, what I'm really worried about is if the two strip boxes at 300w/s are going to be enough to provide a rim light? I guess that's what you would call it.

I need another 1200w/s pack I think.

If my 500 w-s in softbox resulted in f/16 at 4', 300 w-s at 2.8' should have the same f/16 output (a touch more, actually). Using a snoot rather than a stripbox for single portraiture would also help.

Wilt wrote in post #11717721
If my 500 w-s in softbox resulted in f/16 at 4', 300 w-s at 2.8' should have the same f/16 output (a touch more, actually). Using a snoot rather than a stripbox for single portraiture would also help.

For rim lighting? I want something that highlights the length of the body. At least I think I do.

We're supposed to get almost a foot of snow tonight, so it's less than ideal shooting conditions right now. Maybe this weekend...

Village_Idiot wrote in post #11717775
For rim lighting? I want something that highlights the length of the body. At least I think I do.

The type of light (snoot, strip) affects the type of lighting cast, but are all appropriate sources to rim lights, just as they are both employed for hairlight, depending upon the hairstyle and color of the subject.

Wilt wrote in post #11717818
The type of light (snoot, strip) affects the type of lighting cast, but are all appropriate sources to rim lights, just as they are both employed for hairlight, depending upon the hairstyle and color of the subject.

Maybe I'm calling it wrong. I want the lights to run the length of the body like they do in this shot: