SB-910 paired with D600 having trouble with flash sync

[Robert Mitchell]

Hi Wayne,

I searched and now I can't find it. I asked a friend of mine that also shoots Elinchrom and he remembers seeing that spec listed but neither of us can find it now. i don't think I was imagining it but I'm not seeing any mention of it anymore. The only reference to sync speed that I'm seeing now has to do with the Skyports and strobes that work in Speed mode, and that's where they indicate that you can go from normal sync speed of 1/160s up to 1/250s.

Going back to one point that we were discussing, and something I did test myself, was that using a sync cord did not increase sync speed or show any advantage over a radio trigger. While there may be a delay with a radio trigger, that's not making enough of a difference to affect the shutter sync speed. With a sync cable and my 600RX's I'm not able to use shutter speeds that are faster than if I'm using a radio trigger.

 

[WayneF]

Going back to one point that we were discussing, and something I did test myself, was that using a sync cord did not increase sync speed or show any advantage over a radio trigger. While there may be a delay with a radio trigger, that's not making enough of a difference to affect the shutter sync speed. With a sync cable and my 600RX's I'm not able to use shutter speeds that are faster than if I'm using a radio trigger.

Right, the electronic flash unit sync is instantaneous (X sync), no matter how you do it... Hot shoe, PC sync cord, optical slave, all are instantaneous, speed of light so to speak. Radio triggers almost are almost as fast as shutter sync speed, but some can suffer delays. Esp with low batteries.

There is a difference. If you have a camera with a CCD electronic shutter instead of a focal plane shutter, then the camera has no sync issues either. Like with a D40 or D70 camera, you can sync speedlights at any fast shutter speed, like 1/2000 second (if you use a PC sync cord so the camera software won't know the flash is there). These are more crummy shutters, but they are fast (i.e., all the frame is open at once, even fast). But radio trigger delay generally will not sync faster than conventional shutter sync speeds, if even that.

Why radio triggers have more delay, I don't know. I compare it to a voice signal over radio, the voice saying "Do it right NOW!", and then we do it right now, but it takes several milliseconds for that voice to be said and transmitted and listened to and recognized. That is a delay, esp at instantaneous speeds.

 

[daredevil123]

Right, the electronic flash unit sync is instantaneous (X sync), no matter how you do it... Hot shoe, PC sync cord, optical slave, all are instantaneous, speed of light so to speak. Radio triggers almost are almost as fast as shutter sync speed, but some can suffer delays. Esp with low batteries.

There is a difference. If you have a camera with a CCD electronic shutter instead of a focal plane shutter, then the camera has no sync issues either. Like with a D40 or D70 camera, you can sync speedlights at any fast shutter speed, like 1/2000 second (if you use a PC sync cord so the camera software won't know the flash is there). These are more crummy shutters, but they are fast (i.e., all the frame is open at once, even fast). But radio trigger delay generally will not sync faster than conventional shutter sync speeds, if even that.

Why radio triggers have more delay, I don't know. I compare it to a voice signal over radio, the voice saying "Do it right NOW!", and then we do it right now, but it takes several milliseconds for that voice to be said and transmitted and listened to and recognized. That is a delay, esp at instantaneous speeds.

Actually how D40 and D70 achieves the high sync speed is not in the mechanical shutter. They used an electronic shutter which in actual implementation, turn off and on the sensor. IIRC the mechanical shutter still syncs at 1/250s, but any faster, the sensor will turn on and off when the mechanical shutter is full open.

Agree that radios do affect sync speed. The cheaper radio triggers tend to give you lower sync speed due to more latency.

 

[WayneF]

Actually how D40 and D70 achieves the high sync speed is not in the mechanical shutter. They used an electronic shutter which in actual implementation, turn off and on the sensor. IIRC the mechanical shutter still syncs at 1/250s, but any faster, the sensor will turn on and off when the mechanical shutter is full open.

Agree that radios do affect sync speed. The cheaper radio triggers tend to give you lower sync speed due to more latency.

Yes, that is what I just said. The D40/D70 mechanical shutters were not 1/250 second however, they were significantly slower, I've read more like 1/90 second. For faster speeds, it was held open, and the CCD timing was used. This risks blooming in when bright lights were in the frame, at like 1/2000 second shutter, the CCD was uncovered about 20x longer, much longer than the desired exposure.