Black band at bottom of picture with photos taken with strobes.

[william_stearman]

<p >First the equipment that I am using while this problem happens.</p>

<p >pocket wizard Plus II transceiver’s</p>

<p >canon EFS 18-55mm 1:3.5-5.6</p>

<p >Tamron asherical LD Di II AF 18-250mm 1:3.5-6.3 (if) MACRO lens</p>

<p >white background, black background, green/white background</p>

<p >two umbrellas, two soft boxes, one barn door, and one snoot</p>

<p >Fancier studio flash (FAN 160) I have three of these lights</p>

<p >Canon rebel XTi with a Battery grip for it (BG-E3)</p>

<p > </p>

<p >So every time I take a photo with the any combination of the above I get a black feathered band that starts off strong at wherever the cameras bottom is located at, when the photo was taken and feathers out to a great photo. The band of black stays at the bottom of the camera, so if I were to shoot a photo landscape style the black band would be at the bottom; then changing nothing but the camera angle, to say a portrait layout style (vertical) what ever side the cameras bottom was on the black band would be there also. </p>

<p > </p>

<p >However when ever I take the camera outside and photograph things outside the photos are fine.</p>

<p > </p>

<p >It’s very frustrating to not know what causes this.</p>

<p > </p>

<p >Please help.</p>

<p >Thanks</p><div></div>

[frank_skomial]

<p>Reason:<br>

shutter speed is too fast for your flash and additionally some Pocket Wizard delay adds up.<br>

Try slower shutter speed. Do not use the rear shutter sync method.</p>

 

[bob_osullivan]

<p>More specifically, try 1/100th or slower. Then do test shots from there. There are two things that cause this, and the Pocket Wizzard really isn't one of them. This hapens with film bodies which have more of a delay getting the shutter started and with Some studio strobes which have slow firing times. Check the specs on your strobes. You may need to go down to 1/60th. This should be no problem for studio work though.</p>

[BernardMiller]

<p>The advice given by the above two posters is definitely good. Follow it, and your problem should disappear. The <em>reason </em> you are seeing the black band is this:</p>

<p>Your camera has two shutter curtains. When you press the shutter, the first one opens, and then the second one follows it at some point to cover the film/sensor back up and end the exposure. At slow shutter speeds, both curtains will be fully open at the same time for a period. In order to get a faster speed, say 1/500 second, the second curtain begins to close before the first curtain has completely opened--a travelling slit between the two shutter curtains regulates how much time each bit of the film/sensor is exposed to light. The narrower the slit (the sooner the second curtain follows on after the first has begun to open) the shorter the exposure time.</p>

<p>Each camera will have a particular maximum flash sync speed. That is the fastest time at which both shutter curtains are fully open at the same time, allowing the flash to expose the entire surface of the film/sensor at once. If you set your camera on a faster shutter speed than that, as in your example above, the second curtain will have already begun its travel across the film/sensor plane when the first curtain opens completely and the flash fires, blocking the light from hitting the part it is covering and leaving the black band you see above.</p>

<p>All this is explained thoroughly (if a bit ungrammatically in places) <a href="http://www.mir.com.my/rb/photography/fototech/focalplane/">here</a> .</p>

[alonzo_e]

<p>This is the x-sync speed of your camera. You MUST know it for every camera you own as they can actually be different from camera to camera. <br>

Once you memorize it you must not exceed that speed when shooting with studio strobes or any other type of manual light. for speeds above that you will need a Canon flash to strobe for the higher speed. This H mode greatly decreases the flash distance, but it works.<br>

With ambient light there is no sync speed as it is all continuous..</p>