Can someone help we with this problem

[singh]

Hi All,

Am hoping you can offer some assistance here. I was testing out some studio gear I have purchased, with 2 bowens lights and a backdrop. I had the camera in manual mode:

Canon 350d
50mm f1.8
f4.0
1/250
EV Comp: -2

I shot these two pics and got shadows appearing on the image, but not in the viewfinder. Any idea what causes this? I have seen it creeping into some of my other shots with studio lights too, but never this bad. Just wondering if it could be some sort of lens flare/light falling into the lens that is causing a shadow. I was working in a confied space, so it could also be impacted by the positioning of the lights.

1 was setup is rembrandt style, and one with a honeycomb as a highlight, but setup in a mirror to the main light (as in both lights were either side of me, facing towards the subject).

Any advice you guys can offer will be much appreciated.

Pic1:


Pic2:


Thanks in advance for your support/help.

[CaptainNH]

Your problem is nothing more than your shutter speed.

The flash sync speed of a 350D is 1/200s. The black shadow you see is your shutter closing before the flash has peaked.

With the 350D you need to keep your shutter speed at 1/200 or slower to avoid the problem.

With the correct flash (ideally a Canon one) you can use high speed sync to go to faster speeds, but that won't be possible when you're using your Bowens.

[singh]

Thanks a lot for that information! Much appreciated.

I was thinking at the time it may be some shutter speed issue.

So basically, with the setup I have (which uses elinchrom wireless triggers to the lights) I should not use a faster speed than 1/200.

Thanks for that info, it is much appreciated. Would this problem "creep" in at speeds approaching 1/200, should upto 1/200 be perfectly fine? I assume that this will creep in gradually at above 1/200 when it will get worse and worse, or is that not the case?

[CaptainNH]

You will be fine with any shutter speeds up to 1/200s.

Any faster than that you'll see your shutter closing. As you go to faster and faster shutter speeds, you will see more and more black until you have a tiny strip of exposed image.

Why not try experimenting with other shutter speeds too see the effect, you won't hurt your camera and, if you post them up, others will learn something from it too!

[singh]

Sure thing, will test it out this weekend and will give some feedback.

Thanks a lot for your assistance!

[singh]

Some more useful info on sync speeds, with some pics to demonstrate:

tzywen.com - Flash Sync Speed

[Baydem]

There is another technique you can use. Close all lights, and set up shutter speed to 1 sec. Prepare your flashes. Than push the button and push the flash test button (in 1 sec.). You can take different photos. Also this technique helps with high speed photography.