Studio Question - small slave

[illusionest]

hi everyone


i (finally) got a background stand, and a roll of super-white paper.
I have 2 umbrellas and 2 big reflectors, i attach the canon 580ex II and 430ex to the umbrellas.

Now some of my shots have an awkward shadow in the back, not always, sometimes. To eliminate this i can put a slave light behind the model right? (the red arrow)

i want something cheap and i do not want to buy another flash (as it is not even necessary, i believe...).

so what are some suggestions for slaves for putting in the back? Radio-slave? or one of those 'fires-off-when-sees-light' lights? :p

basically, something that can give a bit of 'backlit'?

Thanks guys, i appreciate all your comments :)

[Wilt]

No light can ever fill in the intensity hole that is a shadow left by another light!

Shadows on backgrounds are avoided by DISTANCE between subject and background.

[illusionest]

I see, maybe my subject was too close to the backdrop. hm.


well let me elaborate on the "shadow", its a very light, soft, noticeable gray behind the person. Can I still use back light?

[PacAce]

I see, maybe my subject was too close to the backdrop. hm.


well let me elaborate on the "shadow", its a very light, soft, noticeable gray behind the person. Can I still use back light?
Adding more light to the background will lighten up the shadow but it still won't get rid of it entirely. However, if you light up the background enough to blow it out along with the shadow, then that'll get rid of the shadow on the background.

[Wilt]

Backlight lights the background but does not get rid of shadows! Backlights will lighten the entire backdrop, but it merely adds light equally to all parts of the backdrop so that the shadows are lighter, but so is the rest of the backdrop...leaving the shadow still there. But if you keep the shadow off the backdrop to begin with, the light for the backdrop can allow you to regulate its brightness independent of the brightness of the main subject, so that you can control the 'separation' of subject tonality vs. background tonality.

[PhotosGuy]

i want something cheap I didn't have a shadow on the background, but I did use just a cheap flash on a spare chair here: Simple 2 Light Portrait Set-up (http://photography-on-the.net/forum/showthread.php?t=128857)

[illusionest]

i see, thanks PacAce, Wilt, and PhotosGuy.
I will try to adjust the object and light positions, since its the umbrellas that are causing the shadows.

[Wilt]

so what are some suggestions for slaves for putting in the back? Radio-slave? or one of those 'fires-off-when-sees-light' lights? :p basically, something that can give a bit of 'backlit'?

There are some lights that are optical slaves, and they cast light in a hemisphere. Put directly behind, and close to, the model, they can serve a double purpose, as background light and as a hair/rim light