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01-14-2009, 06:20 PM   #1
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What's goin on here? HELP!

Hello everyone. I've been getting into (off camera) lighting more using flashes. So I eventually got some cactus v2 radio triggers because they are cheap and that works fine with me. They work good for my use, but they are cheap, no doubt.

My problem is that when I trigger a flash using cactus v2, if my shutter speed is too high, it has this weird black area at the bottom of my frame. Here are two shots, one pretty blown out, and one a slightly better. These were taken with Pentax AF-360 flash in one hand, camera in the other, all pointed to the same spot. Shutter speed is 1/180 which is the X-Sync.

This problem happens ONLY when I use the wireless radio triggers. The next two pictures are same shutter speed, same aperture. The first is the flash mounted onto camera. Second is the pop-up flash.

Now I'm fairly new to all this flash, lighting (all dslr) stuff so maybe I just missed something pretty elementary. I do tend to panic when something "different" happens.

But what's goin on here? I've used different lenses as well as different lighting setups. Still get that weird almost shadow like appearance at the bottom. Has anyone had this problem. Did I completely miss a switch on the camera? The latter would be best. Anyways, any help is appreciated.

01-14-2009, 06:22 PM   #2
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You have to slow your shutter speed down. The wireless signal is just not fast enough on these V2s. The black is the shutter closing.
01-14-2009, 06:26 PM   #3
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what you see is that the shutter has begun to close before the wireless flases have triggered,

you say that you use the same shutter speed for both on and off camera,, what is it?

Also, are you doing trailing curtain sync, which needs to be slower to allow for correct exposure.
01-14-2009, 07:49 PM   #4
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I figured that was the shutter, because I couldn't think of something else. And the problem is in the transmitter/receiver combo. I can't say I'm surprised though, for the price, they are dirt cheap. Wish I had the money for something better (like pocketwizards)...

After sitting here for the past hour and a half, I did find that changing the channels on the set up help alleviate some of the problem. I still get a slight "shutter vignette" at 180, but gone by 160. All in all, that is still very slow with many equivalent cameras having sync much faster.

Last edited by paolojackson; 01-14-2009 at 08:02 PM.
01-14-2009, 09:16 PM   #5
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I'm using similar triggers with my K100DS, and sometimes I'll get the same thing. It's usually transient, and will go away on the next shot.

Slowing down to 1/125 will fix it every time (I'm set for 1/2 stops so I can get to 1/180. If you are set for 1/3 stops, you'll only be able to get to 1/160 shutter speed).

It may be a battery issue in your flash or triggers. If the voltage drops, they can become flaky.
01-14-2009, 09:16 PM   #6
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The problem is actually w/ the flash...I get 1/180 w/o problems w/ a Nikon flash.
Bring your shutter speed down to 1/160 or 1/125 and you'll be fine. It won't matter much because the flash freezes motion...

If your transmitter's battery is low, this also can happen.
01-15-2009, 03:38 AM   #7
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Actually, I think the triggers have a pretty wide variability. I use them as well with my Nikon SB24 flashes and I can only sync as high as 1/125th without the black band, but that is fast enough for my purposes.

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