Ghosting when using wireless triggers.

[mccosh]

<p>Hi Matt, Some images are in landscape and some in portrait mode. I also wondered if the VR lens was somehow refocusing half way through the shot so have dome some test shots with VR on and off same problem so doesn't look like the VR is at fault here.<br /><br />Ann, I am currently running a test on using different channels and early indications are that we may have fixed the problem. If this is the case I can't work out why we should get this ghosting effect.</p>

[ann_overland]

<p>From the page I linked to:</p>

<blockquote>

<p>4 channels connection (radio):4 channels connect combination available for switching to a good connection to prevent jamming.</p>

</blockquote>

[ann_overland]

<p>Wouldn't that mean to prevent interference from other radio waves?</p>

<p>Are the operating frequency - 433MHZ - approved for this use in your country? You don't have to answer that, just think about it. If it is not, you might be blocking or interferring with some vital radio equipment.</p>

[mccosh]

<p>Hi Ann, I agree can't see how a different channel would make any difference. I presume that they have been approved for use in New Zealand otherwise they wouldn't be allowed to sell them here.</p>

[bob_sunley]

<p>At a shutter speed of 1/50 of a sec, you have motion blur, the camera is moving during the exposure. Normally, the flash freezes one image, available light creates a second, if the flash units aren't synced, you can get multiple frozen images. Just like in your picture.<br>

Nothing to do with metering modes. <br>

Try the same setup again, but pan the camera as you push the button, the out of sync flashes will show up even better.</p>

[mccosh]

<p>I hear what your saying Bob, But I doubt I had camera movement to that extent. I can shoot as low as 1/30 sec without ever having camera blur (the occasional motion blur when the subject moves). In the thousands of photos I have taking I have never experienced camera blurr at this shutter speed. i was also using a VR lens that's good for 2 - 3 stops. </p>

[mccosh]

<p>It has also happened while shooting in my studio with the camera on manual and set on 125 sec F11. </p>

[ann_overland]

<p>Did the problem go away when you swithed to another channel? </p>

[bob_sunley]

<p>Well out of sync flashes don't form images in two places on the sensor unless A., the sensor is moving, B., the object is moving, or C., the VR is moving the image on the sensor.<br>

Look closely at the white flowers against the groom's jacket, you can see the brighter image to the left, the motion blur in the middle and a bright spot on the right.<br>

Did you have VR turned on? Can't tell from the exif data in the photos as your Adobe software stripped it off.</p>

[mccosh]

<p>Hi Bob, yes VR was turned on. I think this might be the problem as well is that somehow the VR lens is trying to refocus mid shot.</p>

<p>Ann, Still doing the test on the different channel so far so good but want to thoroughly test it before declaring that it is fixed as I agree with Bob can't see how this could cause the problem.</p>

[bob_sunley]

<p>I think you'll find the VR is optimized for landscape format images, rotating the camera and lens 90 degrees for a portrait shot just might confuzzle it a bit.</p>

[mccosh]

<p>This happens in both Landscape and portrait format and only happens when using the wireless flash triggers.</p>

[kevin_break]

<p>Sorry I zoomed thru the responses... you did try a fixed focal length lens without stabilization in addition to the shots with VR ?</p>

[bob_sunley]

<p>Well the image isn't wrong, the flash triggers can't move the camera or subjects, but they could possibly mess up the VR electronics, moving the image in the process. There is a problem with some flash triggers and Canon flashes I believe.</p>

 

[mccosh]

<p>I totally agree with you Bob. I'm sure it isn't camera shake I'm pretty steady and why does it only happen when the wireless flash trigger is in use. <br /><br />Another thought I have is that my camera's are getting pretty close to their max shutter count of 100K shots. Is this some how showing a problem with the shutter when the flash triggers are in use. As I type this I realise how this sounds but still it's in the back of my mind.</p>

[paco_rosso]

<p>In response to:<br>

"<a href="../photodb/user?user_id=5180877">John McCosh</a>, Dec 05, 2012; 12:58 a.m.</p>

 

<p>This happens in both Landscape and portrait format and only happens when using the wireless flash triggers."</p>

<p>Then I guess it is a delay in the transmission, the flash is emiting light for a long time, ¿Maybe thereis TWO shoots too near in time?</p>

 

 

[paco_rosso]

<p>The only way (I think) to get a "open flash" (this technique) with a 1/125 obturation time is to move the camera (or the subject) at a quick speed... (/set mode ironic on) ¿Did you shoot from a car in movemetn? (/set mode ironic off)</p>

 

[ann_overland]

<p>Lorne said:</p>

<blockquote>

<p>The radio trigger on the camera is doing something ugly to the camera electronics.</p>

</blockquote>

<p>This is a plausible cause. And if it is only happening when certain channels are being used, it is tempting to believe that interference with the radio waves is the cause. It could cause problems with the electronics in both the transmitter and the camera, I guess.</p>

[bob_sunley]

<p>It can't be the shutter unless that is causing the camera to move. Try using your triggers and camera with a non-VR lens, I would almost bet the farm the problem disappears. :)</p>

<p>The image has shifted relative to the sensor during the 1/50 sec the shutter was open, only two possibilities, camera movement or the VR optics shifted the image. If the camera didn't move, it has to be the VR. Or maybe your image sensor isn't tightened down inside the camera. Out of sync flashes didn't cause the problem, they just document it.</p>

 

[rodeo_joe1]

<p>Wearing <em>trainers</em> at his wedding! What was that groom thinking?</p>

<p>I'll stick in my thoughts based solely on the images posted. I've only quickly scanned the responses, so please forgive any duplicated suggestions.</p>

<p>The double image(s) <strong>must</strong> be caused by a double flash. Reasoning: The double image occurs only on the couple and the foregound flowers, and not on the background. The double image is also reasonably sharp. This means that whatever light is providing the double image must fall off rapidly before lighting the tree in the background and must be of short duration. Ergo, it's a double flash.</p>

<p>The cause of the double flash is a bit more difficult to puzzle out. My guess is that the triggers are responding to their own flash, to the flash of other wedding guest's cameras, to changes in ambient light, or are just plain faulty and one of them has an intermittent delayed response. However, why the shutter is staying open long enough to capture a double flash is another puzzle entirely. Using the maximum synch speed of the camera might help. This is at least 1/250th sec on most Nikons. Check your menu options for any panorama or HDR settings too.</p>

<p>My advice would be to just bin those crappy Nicna things or send them back. Get proper <strong>radio</strong> triggers that can't be interferred with by spurious light, infrared or other flash signals. For about the same price as those Nicnas you can get <a href="http://www.lightingrumours.com/wp-content/uploads/2010/04/pt04-ishoot.jpg">iShoot radio triggers</a>. I've used a set of these (type A) for about 2 years now without a single problem. No, you can't trigger them using the camera's little popup flash - but that's a good thing isn't it? You might also want to think about using a lighting setup other than what's basically "copy lighting" John. Giving some 3D modelling by using your light from primarily one direction would help.</p>

<p>Edit: Whooa! Just noticed that the flashes were at 1/32 power and 3 metres away!? That doesn't make sense. It would mean the ISO setting must have been set way high to get a flash exposure that bright, and yet the ambient light looks lower than that of the flash. I don't think we're getting the full story here.</p>

[ann_overland]

<p>Another theory:</p>

<p>The radio wave interference might effect the triggering radio waves transmitted from the transmitter to the receivers. I guess that could cause the receivers to behave in unexpected ways. Maybe the result is an out-of-sync speedlight firing?<br>

<br /> Edit: I didn't read Joe's answer before writing this one :-)</p>

[bob_sunley]

<p>Foreground has the double image too. The background is blurred enough you can't see it, plus the available light overpowers the flash.</p><div></div>

[ann_overland]

<p>There seem to be only one flashlight reflected in their eyes. Is it the left one?</p>

[bob_sunley]

<p>Probably the camera right flash, you can also see the shadow of his nose on his right cheek. Interesting, the full length image has no eye catchlites in it at all, probably disappeared when reducing it for web size.</p>

[mccosh]

<p>Thanks for all your responses and suggestions. I'm leaning towards a problem with the VR on the lens. Have gone back through my images I see that these are only happening with one lens / camera combination. I have switched lenses on this camera and will do some tests to see if this fixes the problem. <br /><br />Maybe the flashes are out of sync and this is highlighting a problem with the lens VR system. <br /><br />Rodeo, I would say your right looking at the images was just going off memory that the flash units were set at 1/32 power. I know that's what I finally settled on after taking a few test shots and this was probably one of the earlier test shots that obviously had the flash units set on a higher setting. Good spotting.<br /><br />John</p>