Studio Problem - Help!

[tba20042003]

Hi,
I have uploaded 2 photos into my General Album, called Studio Problem, and Studio Problem 1. One is taken with the camera in landscape format, the other in portrait format. Apart from the orientation of the camera, all the other settings as well as the flash head settings remained exactly the same. I had 2 flash heads, one front right at 45 degrees and one front left at 45 degrees, both on the same power settings.
My problem is that on the photo taken in portrait orientation, there is a dark area to the right of the subjects on the white backdrop; this does not happen when the camera is held in landscape, as you can see from camparing the 2 photos.
Please does anyone have any theories as to why this is happening, and ideas on how I can overcome it?
Thank you in advance.
Tom

[GeoffWessex]

I'm not an expert on studio flash of any kind..... but both of the shots are way over-exposed. As to which side of the background the dark area might be, that fades into insignificance compared to the over-exposure, which is probably, in part, caused by the black clothing (remembering your camera's meter is trying to give an EV to record grey).

[greenwing]

I wonder if 1/200 is just too fast for your studio flash setup, and you're starting to see tha shutter closing before the flash fires. I fancy that the lower edge of the landscape shot is just a little bit dark, too. Try setting shutter to 1/160 and see if it goes away.

Chris

[tba20042003]

That sounds great advice Chris - I'll give it a try.
Many thanks.
Tom

[cosmicma]

definitely to do with shutter speed i would go for 125th or less
on cropped sensors you can get away with 1/250th of a second before the the curtain gets in the way but on full frame it quite a bit less which i found out when i was playing with my 5d and studio lights

high speed sync eliminates the problem but most studio lights don't have that option

[tba20042003]

Thank you so much.
Much appreciated.
Tom

[Cathus]

I had the same problems with my system, although the shutter sync speed is 1/250, I find using studio lights at this speed causes the black edge, lowering the shutter speed solves this

[tba20042003]

Cheers - thank you.

[thefonz78]

I've just started playing around with flashes myself so no expert, but if you want the backdrop to be totally white you need to light it up. If you only have the 2 flashes point one at the backdrop use the other at a 45 degree angle to the subject then use a reflector on the other side. If you don't have one a large piece of white card or cooking foil around some card will do a good job. You also have the flash up to high the faces are overexposed.

[tba20042003]

Thank you Robert - as you can tell, I'm very inexperienced, and your advice is very much appreciated.
Cheers.
Tom