Confusion with lighting and flash sync speed. Help.

[jwbryson1]

I set up my new black backdrop, put my camera in manual mode and adjusted the setting to f/4.5 and 1/640 shutter speed which totally eliminated all signs of the backdrop and all ambient light which was my goal. I put my subject in front of the backdrop, took my SB-700 off camera and angled it to bounce light off the ceiling. When I took the shot, however, the shutter speed was 1/200 which is my D90's flash sync speed, and of course the lighting is a bit hard, the backdrop appears and there are shadows. Not what I wanted or expected.

So how do I fix this? What am I doing wrong (probably a lot of things)? My goal is to have my subject lit and the background totally blacked out.

Thanks.

 

[analog.universe]

In order to have the subject lit and the background black, you need lots of light falling on the subject and very little or none on the background. If you're bouncing off the ceiling you're lighting the background as well. Ideally you want to use something like a softbox and possibly even a gobo or barn doors to create light that is soft, but still prevented from reaching the background. Increasing the subject to background distance makes this easier as well. If it takes 4.5 and 1/640 to eliminate ambient, I'd suggest turning the ambient down maybe? I have plenty of shots where I've blacked a background at 3.5 and 1/200.

 

[Trever1t]

decrease your ISO to native and stop down your aperture until your ambient is 3 stops under exposed at or below your sync speed. shoot thru a diffuser of sorts at a lower power to illuminate your subject, not the whole room. Just a beginner strobist here but that's my best guess.


edit: I see I am too slow to type

 

[Kerbouchard]

Put more distance between your subject and your background and try feathering your flash away from the background. You can also lower your aperture to around f/8 or so.

 

[jwbryson1]

Newbie mistakes I'm making. This is a really small room and my subject is about 12" in front of the backdrop. I have very limited space to work and 4 windows behind me with honeycomb style window fittings which are lighting the room more than I'd like.

I like the idea of shooting at 1/200 and stopping down the lens. That is so obvious but I did not think of it. I also understand the subject needs to be farther away from the backdrop. Thanks for the reminder.

Newbie back to work now. Thanks. Maybe I'll post some results later today.

EDIT: I adjusted my f-stop to f/14 and I can now shoot at 1/80 and totally eliminate the background. Thanks for the help.

EDIT 2: Here's what a newbie I am. I didn't bother checking my ISO before I did my initial settings at f/4.5 and 1/640. It was still at ISO 800 which is the setting I was using at a Halloween party last night. Silly mistakes.

 

[BuS_RiDeR]

As far as I know.... When using flash or strobes with your camera's sync speed... That will help you get a proper exposure.

I suggest a smaller aperture (start with /f8.0 or even smaller.

Another option might be to move your backdrop back, a bit more away from the subject.

 

[Trever1t]

Definitely move your subject as far forward as you can and still keep the composition. 12" is too close.

 

[jwbryson1]

Yeah, I'm going to move the backdrop to another room. I'm having to dance around a moderate size piano and some floor lamps to even get a shot.

 

[Jan Matis]

You can still use faster shutter speed. You need to be on full manuall mode. more for example on lightenupandshoot.com

 

[gsgary]

Newbie mistakes I'm making. This is a really small room and my subject is about 12" in front of the backdrop. I have very limited space to work and 4 windows behind me with honeycomb style window fittings which are lighting the room more than I'd like.

I like the idea of shooting at 1/200 and stopping down the lens. That is so obvious but I did not think of it. I also understand the subject needs to be farther away from the backdrop. Thanks for the reminder.

Newbie back to work now. Thanks. Maybe I'll post some results later today.

EDIT: I adjusted my f-stop to f/14 and I can now shoot at 1/80 and totally eliminate the background. Thanks for the help.

EDIT 2: Here's what a newbie I am. I didn't bother checking my ISO before I did my initial settings at f/4.5 and 1/640. It was still at ISO 800 which is the setting I was using at a Halloween party last night. Silly mistakes.

Shut your curtains

 

[jwbryson1]

You can still use faster shutter speed. You need to be on full manuall mode. more for example on lightenupandshoot.com

I was in full manual mode.

 

[jwbryson1]

Newbie mistakes I'm making. This is a really small room and my subject is about 12" in front of the backdrop. I have very limited space to work and 4 windows behind me with honeycomb style window fittings which are lighting the room more than I'd like.

I like the idea of shooting at 1/200 and stopping down the lens. That is so obvious but I did not think of it. I also understand the subject needs to be farther away from the backdrop. Thanks for the reminder.

Newbie back to work now. Thanks. Maybe I'll post some results later today.

EDIT: I adjusted my f-stop to f/14 and I can now shoot at 1/80 and totally eliminate the background. Thanks for the help.

EDIT 2: Here's what a newbie I am. I didn't bother checking my ISO before I did my initial settings at f/4.5 and 1/640. It was still at ISO 800 which is the setting I was using at a Halloween party last night. Silly mistakes.

Shut your curtains

Don't have any.

 

[indioli]

pin a throw over the windows?

 

[KmH]

Newbie mistakes I'm making. This is a really small room and my subject is about 12" in front of the backdrop. I have very limited space to work and 4 windows behind me with honeycomb style window fittings which are lighting the room more than I'd like.

I like the idea of shooting at 1/200 and stopping down the lens. That is so obvious but I did not think of it. I also understand the subject needs to be farther away from the backdrop. Thanks for the reminder.

Newbie back to work now. Thanks. Maybe I'll post some results later today.

EDIT: I adjusted my f-stop to f/14 and I can now shoot at 1/80 and totally eliminate the background. Thanks for the help.

EDIT 2: Here's what a newbie I am. I didn't bother checking my ISO before I did my initial settings at f/4.5 and 1/640. It was still at ISO 800 which is the setting I was using at a Halloween party last night. Silly mistakes.

Shut your curtains

Don't have any.

Improvise.

 

[Derrel]

We used to use Foam-Core boards as window-blockers.