small studio lighting help PLEASE

OdiliaB

I recently bought a small personal lighting studio package to supplement my Canon Rebel xt. I have a radio wireless hotshoe that triggers three remote flashes. Everytime I get my lighting close to right I get a dark shadow line. I read it has something to do with "vertical wiping"...

SOMEONE PLEASE POINT ME IN THE RIGHT DIRECTION.

equipment is from Squareperfect if it matters.

Thanks you brillant photographers!:clap

mr peas

Hey that happened to me before. When I took images using separate aux flashes, some of my images came with a black fade on the side, it was really weird. I saved one of those images just for reference:



What is up with that?

OdiliaB

I'll post an example as soon as my other photos download.

LiquidAir

Make sure the shutter speed on your camera doesn't exceed the flash sync speed. I don't know what the sync speed is for an XT, but on my 5D the official sync speed is 1/200s for on camera flash. When I am firing with a wireless trigger (either a Pocket Wizard or an ST-E2) I have to drop the sync speed by 1/3 stop to 1/160s. Generally when shooting in the studio, I set my camera on manual with a shutter speed of 1/160. Then I work with the flash power, aperture and ISO to get the exposure right.

OdiliaB

Can you break it down a bit more Liquid...1/200 sec or auto are my settings for flash sync???

LiquidAir wrote:

Make sure the shutter speed on your camera doesn't exceed the flash sync speed. I don't know what the sync speed is for an XT, but on my 5D the official sync speed is 1/200s for on camera flash. When I am firing with a wireless trigger (either a Pocket Wizard or an ST-E2) I have to drop the sync speed by 1/3 stop to 1/160s. Generally when shooting in the studio, I set my camera on manual with a shutter speed of 1/160. Then I work with the flash power, aperture and ISO to get the exposure right.

LiquidAir

OdiliaB wrote:

Can you break it down a bit more Liquid...1/200 sec or auto are my settings for flash sync???

The flash sync speed is the fastest shutter speed for your camera where the shutter is completely open when the flash fires. The black bar you see is the shadow of the shutter at the time the flash triggered. To make it go away you have to use a slower shutter speed. The proper speed to use is different for every camera body; I looked up the number for the XT (quick google search) and it is 1/200s just like the 5D.

The Auto setting on your camera will generally not work well with studio strobes beause unlike the Canon branded strobes, they don't support TTL metering. This means you will need to take care of all the settings manually. Assuming you don't plan on using any ambient light in your exposure a good basic setup is to set your shutter speed to 1/160s, your ISO to 100, your strobe to 1/4 power and adjust the aperture until you have the proper exposure.

digismile

OdiliaB wrote:

Can you break it down a bit more Liquid...1/200 sec or auto are my settings for flash sync???

What he is saying, is whatever mode you use on your camera, Manual, Aperture Priority, etc., be sure that the shutterspeed of the photo is 1/200 of a second or LESS. The sample photo was 1/320 of a second.

The reason why you need a relatively slow shutterspeed is because of the way your shutter actually works. See this post regarding the same issue.

You basically aren't exposing the entire sensor at exactly the same time. You are actually exposing a moving strip across the sensor. So in this case, the illumination from the flash is gone before the right side of the picture was exposed on the sensor.

As stated by Liquidair, slow down the shutter speed and all will be good

Regards,

mr peas

Ahh IC. That makes sense. I was shooting in manual compensating for the strong flash by increasing the shutter speed. Totally forgot about the maximum flash sync speed. Durr.

Thanks, that makes a whole lotta sense now.

LiquidAir

mr peas wrote:

Ahh IC. That makes sense. I was shooting in manual compensating for the strong flash by increasing the shutter speed. Totally forgot about the maximum flash sync speed. Durr.

Thanks, that makes a whole lotta sense now.

The duration of the flash is on the order of 1/10,000s which faster than any shutter speed on your camera. If the flash is too bright you can lower the strobe power, move the strobe farther away or reduce the aperture. Changing the shutter speed has no effect.

SloYerRoll

LiquidAir wrote:

The duration of the flash is on the order of 1/10,000s which faster than any shutter speed on your camera. If the flash is too bright you can lower the strobe power, move the strobe farther away or reduce the aperture. Changing the shutter speed has no effect.

To make sure LA's comment makes sense...

Aperture controlls strobe lighting (any light triggered by your camera)
Shutter Speed controlls ambient

While you can controll ambient w/ aperture. This is a golden rule of strobe lighting.

HiSPL

http://strobist.blogspot.com/


All you need to know is here......

dmmattix

Wireless

HiSPL wrote:

http://strobist.blogspot.com/


All you need to know is here......

Including the fact that the inexpensive wireless flash triggers can force you to reduce your shutter speed all by themselves. Probably something to do with a delay the wireless systems put in the flash system.

Regards,

Mike