I'm sorry to burden you all, but I need help...

[nrellas]

Like I said, sorry for the dumb stupid question, but after hours of shooting and searching I need help.

Problem: Everytime I shoot with my strobes I get a black line down one side of the frame.

What I am doing (I'm assuming its wrong): I'm using two strobes attached to my 1d and I am metering with a sekonic L-308s. I am firing the strobes and then adjusting my camera settings to the reading it gives me. When I shoot at .5-1 stop under there is no more black line.

I cannot figure out what I am doing wrong, but then again I'm just a 17 year old trying to teach himself...

ANY help is appreciated.

Nick

[PacAce]

You might be having a shutter speed "syncing" problem. What shutter speed are you using? If it's faster than 1/250, set it to 1/250 or slower.

What exposure mode are you using? What doesn't make sense is what you said about the black line going away when you shoot a little under-exposed. Are you adjusting the shutter speed or the aperture to get it to under-expose?

[johnms88]

Use a longer shutter speed. This will (should) fix your problem.

Id go into the technical jargain, but im not the best person to be explaining sync speed and all that crap.

Good Luck!

[SkipD]

Nick - read your camera manual regarding the "max sync speed" for flash use. That shutter speed is the fastest speed at which the shutter is fully open.

A focal plane shutter has two "curtains" (old style, usually rubberized cloth) or two "blades" like current DLSR designs. When the shutter opens, the first curtain or blade travels across the film/sensor space, exposing the film/sensor to the light coming through the lens. At shutter speeds at or slower than the "max sync speed", the first curtain or blade travels all the way across the film/sensor plane prior to the trailing curtain or blade starting its travel to close the light path to the sensor/film.

A burst of light from an electronic flash unit has a very short duration, and it needs to be "syncronized" (timed) with the shutter so that the burst of light occurs while the shutter is fully open. If you use a shutter speed faster than the max sync speed, the trailing curtain/blade has started its travel, covering the film/sensor plane before the flash is fired. That's what you have been seeing.

Here is a link describing focal plane shutters (http://en.wikipedia.org/wiki/Focal_plane_shutter) to help you understand a little better. The article describes the older rubberized cloth shutters, but even though the hardware is different with today's metal blade shutters, the concept is almost identical.

[Converge]

Use a longer shutter speed. This will (should) fix your problem.

Id go into the technical jargain, but im not the best person to be explaining sync speed and all that crap.

Good Luck!


Im thinking his problem may be that he is using TOO long of a shutter speed already

[taygull]

Im thinking his problem may be that he is using TOO long of a shutter speed already


I'm thinking to long would be 30 seconds....too short would be higher than his max sync speed........as the bottom number gets bigger the shutter is open for a "shorter" period of time...so longer shutter speed would help the problem....right.:rolleyes:

The only reason I can think of while in studio to use a speed of 1/250 or 1/200 is if you are worried about camera shake or subject motion...lots of motion like kids.

I adjust my shutter speed to control ambient light as the flash will freeze most camera shake and motion blur. I shot a bunch of portraits yesterday and my shutter speed was around 1/60th. I really don't worry much about the shutter speed as long as I'm using a tripod and my cable release.

Pushing the shutter speed close to the sync speed really has very little value....at least in my mind. Unless of course you want to make sure you reduce your ambient light.

[johnms88]

Ok, heres how we solve this.

Post an example image :)

[Clark]

Ok, heres how we solve this.

Post an example image :)
Along with EXIF data

[Converge]

Along with S.S. number

[PacAce]

Along with S.S. number

Shutter speed will be in the Exif, no? ;)

[Clark]

:D:lol:Along with S.S. number