can anyone help my strobe probs

[jimaroo]

i have one strobe light, and a small minolta flash.
im trying to do the effect of a really over exposed backround and have the subject exposed correctly.

i cant figure out where to put the lights to get a good exposer.

see the strobe is an excaliber xp 1600 and it goes off when my other flash goes, i also have a flsh meter too.
but the little flash has a cord that is attached to my camera at all times so that flash can't go very far from me. any way here is what i have done.

i had the little flash on the left pointing at my backdrop, witch is just some fabric from walmart, and the big flash is off to my right with a reflecting umbrella pointing at the subject..


i don't know what im doing
if you could point me off in the right direction that would be great.

 

[markc]

In order to overexpose the background and keep the subject good, it needs to be overlit compared to the subject. Is the flash on manual and turned all the way up? You'll need to have the camera on manual and set to where it was when this was taken. If you cant turn the flash up any more, you'll need to turn down the strobe and expose more.

Keep in mind that I don't work with flash and this is all just theory.

 

[jimaroo]

thanks for the advice

 

[bigfatbadger]

The light that is lighting up the background should be one stop higher than the light that is lighting the subject. You can also use a spill kill to make sure all the light is pointed at the background or move your subject quite far forward so no background light goes onto them. Then dodge it when you go wrong!

 

[mysteryscribe]

The one stop rule is good for burning out background details like the seam or crease. It makes for a white glow on that type background.

With a Rembrant type background your back light actually controls the color of the backgorund. If you over expose the back ground it will give you a bright color and high luminescence. However that is not always what you want. Sometimes the Rembrant is best dark and dreary but you still dont want that front strobe light shadow on it. As a rule of thumb you should go the one stop, but know that by lowering the intensity of the light you will darken the background changing the mood of the shot.

Your shot above is perfectly balanced, what you are asking is to burn out the background and that is one stop min over. What you really have to do is experiment to find the settings that work for you. Usually there are only two you need... One for burn out over exposed in the rear, or balanced both lights the same intensity.


Why would you want a darker background you ask, darker backgrounds usually do better with some hair colors. The boy above would look good on a hot (over exposed) background while a true pale blonde or even red head would not. A cool (perfectly exposed) background Usually not always but usually is what you would want for him or her. In order for the skin and hair not to get lost in the stark white of the background.

Product shots are the same thing. But I'm sure this is much more than you wanted to know.

 

[Christie Photo]

And remember.... the meter is telling you how to achieve 18% refletancy... grey. To achieve white, you'll need 2 1/2 times the light. Think of it this way: Let's round up the 18% to 20% so the math is easier. If one unit of light at 20% is used to properly expose the subject, then you need five units to achieve white. 5x20=100, or 2 1/2 stops more light reflecting off the background.

Pete

 

[jimaroo]

thanks you guys that helps some. but when i did this the meter read f11 on the bg. so does that mean i should put my fstop to 9 so that way it would over expose it. that would i thought that i should do but then if i do that its also going to overexpose my subject. the picture above was set at 60 for the shutter, and f11.

i don't know i guess ill just shoot around until it looks good, you can do that with digi..


but what do you guys think about the exposure on the boy is that ok?

 

[mysteryscribe]

The boy is fine I might have given it one more stop of exposure but I always go for the high key at least a little.

You should take two reading with your flash meter. the background meter should read only the backlight strobe. If your front strobe read f11 your back strobe should read f22 or 32 which isnt hard since the distance from backlight to the wall is close.

Wait a minute, you are using a seperate backlight from the side. YOu should fire only that light to read the backlight. then when you get that figure set your front light to hit the boy two stops lower... then set the camera that way.

If the back light is f11 set your front light for f 5.6 and then shoot the camera on manuel with that setting. That should do it.

You might need to put a piece of cardboard on the flash head to direct the light away from the boy and toward the background from that side.... strobes all of them fine in a funnel shape. It might spread to overlight one side of his face.

Hope that helps.