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This is my very first day of shooting with flash and remote flash. And picture turned out like this: Bottom half of it is black. I have no idea what has caused this and how to prevent it? I just know that after this I shot a few more frames without flash or only with the camera's built-in flash and they were fine so I know the camera is not broken. When I read the photo EXIF info this is what I had: 1/400 sec with f 2.8 and 60mm. My flash is a manual flash and its power was on 1/32 and zoom on 70mm.
No specific reason for these numbers, I was only experimenting. Also I had set the exposure compensation of the camera to -5.00 in the hope that it would make the background darker and the foreground look more 3D because of the flash.

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    Also my off camera flash was wirelessly firing with Cowboy Studio remote triggers. Could that be it? – Brandon Apr 23 '15 at 3:38
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You're shooting with a shutter speed faster than your sync speed (most likely 1/200 or 1/250). Your camera's shutter consists of two curtains -- the first one opens to begin the exposure, and the second follows it -- closing to end the exposure. At speeds slower than your camera's sync speed, these two curtain movements allow at least a tiny fraction of time between opening and closing, but at faster shutter speeds, the closing curtain is actually chasing the opening curtain, creating a moving slit of exposure. A flash occurring during such an exposure is only going to illuminate part of the sensor - hence, the dark bar.

This is a bit tricky to picture, but this video shows exactly what's happening with those curtains:

https://www.youtube.com/watch?v=CmjeCchGRQo

  • Thanks, so as far as how to make sure this doesn't happen, I should always make sure when taking pics with flash, my shutter speed should be faster than 1/250? – Brandon Apr 23 '15 at 3:57
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    Check the flash sync speed of your camera - it's likely 1/200 or 1/250. It's possible to go faster than that with a flash capable of High Speed Sync, but that won't be an option with a manual flash. – D. Lambert Apr 23 '15 at 4:01
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    Also, I've encountered minor lag with radio triggers when on the fastest sync speed before and so I often dial it back a touch to account for it. The better the trigger quality, the less this is likely to happen. – John Cavan Apr 23 '15 at 7:29
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    @Blake You need to make sure the shutter speed is either at the sync speed or slower. – Michael C Apr 24 '15 at 1:10
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You exceeded your camera body's sync speed. The shutter speed in focal plane cameras, like most dSLRs, is determined by the gap between the 1st and 2nd shutter curtains. The bigger the gap, the longer the shutter speed. At a certain shutter speed (known as the maximum sync speed of the camera), that gap is only barely large enough to uncover the sensor all at once. Once the speed goes faster, that gap becomes smaller than the sensor. Because a flash burst is typically much faster than your shutter speed, if you go faster than your sync speed, the curtains will be covering either the top or bottom (or both) of your sensor and only the bit uncovered by the slit between the curtains is exposed to the flash burst. Most dSLRs have a sync speed around 1/200s.

If you get a TTL flash that can perform HSS, or high-speed sync (aka focal plane sync or FP sync) and your camera can do it (entry-level Nikon bodies cannot), you can get around this restriction by having the flash pulse out light so that the entire frame will be evenly illuminated by the pulses as the slit travels across the sensor. But most radio triggers cannot communicate the HSS signaling. This will, however, cost you more power. And only radio triggers that can communicate TTL can communicate HSS. So the camera, flash, and triggers all have to be able to communicate HSS for you to have this feature with off-camera flash.

The pop-up flash on most cameras is also incapable of HSS, so if you look at those test images you took with the pop-up flash, you'll probably find the camera adjusted your shutter speed to be at your camera's maximum sync speed.

See also: Neil van Nierkerk's article on high-speed sync.

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1/400 second definitely exceeds your cameras maximum sync speed, which causes the black band. Try 1/160, or maybe 1/200 second.

But in some other cases, we might not have exceeded the cameras maximum sync speed, but cheap radio triggers are notorious for causing a delay, and not being able to keep up with that max sync speed. Just lower your shutter below max sync until it works OK.

Run-down batteries in the radio trigger can make this much worse. Try fresh batteries first.

But 1/400 second is the first obvious problem.

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You're probably using a shutter speed faster than your cameras maximum sync speed. check your camera's specs, and use a slower shutter speed. If you're using off camera flash with inexpensive third party triggers, you almost undoubtedly should be running both camera and flash in manual mode as well.

  • run it manual, (typically)
  • always keep shutter speed below the cameras flash sync speed rating,
  • use cameras aperture, ISO, and flashes power level(if adjustable) to control flash exposure
  • variations on shutter speed (always below max-sync though) can be used to mix ambient light in with the flash's output

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