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stop motion - what am I doing wrong?
http://www.paulcbuff-techforum.com/viewtopic.php?f=8&t=832		 Page 1 of 2
Author:  atomicskil [ Fri Sep 03, 2010 4:49 am ]
Post subject:  stop motion - what am I doing wrong?
hi all, I have been working on a series of dancers/gymnasts doing athletic moves, mostly jumping, some spinning, some of both. I've got my Einsteins set for action and at full power. I'm really not able to tell a difference in their motion stopping power between any of my other lights (ultra zap1600 or AB 800). no matter what I do I'm getting an unsatisfactory motion blur.
The image below was taken at 1/160th, f 11 at iso 125. an exposure without the flash at the same settings provides a completely dark slide. I use a pocket wizard to trip the lights (if an when they play nice together).
Note her foot. It is no doubt the fastest moving thing in the photo, but it seems that this jump should be well within the reach of stopping power for the Einsteins. am I wrong? am I doing it wrong?
Image
Author:  Jeff Jessee [ Fri Sep 03, 2010 9:00 am ]
Post subject:  Re: stop motion - what am I doing wrong?
From all the published information, unlike most lights, you get shorter bursts of light from the Einstein IF you REDUCE the power. You must have the lights far from the subject, guessing from your exposure numbers. (Or you are using an inefficient modifer.) Try closer and 1/4 power, in "action mode" , and you should get great action stopping. And have as little ambient light as possible, and use the highest shutter speed that syncs with your camera. At even 1/2 power, the flash burst should be about 1/2000 sec. in action mode, even shorter at 1/4 power. (Action mode gives you shorter bursts, at the expense of more variation in color temp. as you change power.)

Jeff Jessee
Author:  Technical Support [ Fri Sep 03, 2010 9:03 am ]
Post subject:  Re: stop motion - what am I doing wrong?
Einstein set to full power will be its slowest flash duration. It will be the same in color or action mode (as the IGBT is really not doing anything at full power). It will also be approximately the same as the UZ1600 at full power (actually a little slower) and slower than a B800 at full power, but you have twice the power of a B800. Where the action stopping comes in is as you dial the power down. Dial an Einstein down half a stop, and it is faster than a B800, but with 50% more power. Dial it down a full stop, and it is twice as fast as a B800, but with the same power.

If you dial down the UZ or AB, the durations will get longer.
Author:  Luap [ Fri Sep 03, 2010 9:13 am ]
Post subject:  Re: stop motion - what am I doing wrong?
The issue is that you used them at full power. Like all IGBT lights such as Grafit and other very high end IGBT lighting systems, flash durations at absolute full power is no shorter than conventional nonI IGBT lights. The extremely fast action stopping capability only takes place as power is reduced from Full Power.

This has been well publicized. Please see very complete independent review at http://www.robgalbraith.com/bins/multi_ ... 0053-10715 This is discussed in detail in the operating manual that came with the Einstein manual that came with the unit and which appears here http://www.paulcbuff.com/manuals/e640prelimmanual.pdf complete with charts of flash duration VS power in both color and action modes.

Unlike conventional light, whose flash durations lengthen with power reduction, Einstein durations decrease very rapidly as power is reduced.

So operating with power reduced one to two f stops, particularly in Action Mode, will result in razor sharp shots. As demonstrated in photos posted by Rob Galbraith - preeminent expert in this art.
Author:  Jeff Jessee [ Fri Sep 03, 2010 9:16 am ]
Post subject:  Re: stop motion - what am I doing wrong?
Just studied your photo again, and there is something odd going on there that may not be related to the burst speed of your lights. on the leg, one side of the leg is sharp, but the other side is VERY blurred. Same with the foot. The little toe looks alright, but the big toe is smeared all over the place. It would seem to me that one side of the leg cannot be moving that much faster that the other side!!! I would look to some other cause, maybe a bad smudge on one corner of the lens, or something wrong with the camera shutter. Maybe some more technically savvy people can give you other possible causes.

Otherwise, nice photo, by the way.

Jeff Jessee
Author:  Technical Support [ Fri Sep 03, 2010 9:45 am ]
Post subject:  Re: stop motion - what am I doing wrong?
the leg looks like it is moving from upper left to lower right. Leading edges always appear to blur more than trailing edges.

However, another question to be asked is what light and at what power was used for the background? If it is a slower duration flash, particularly one at such a high power, then it can still lead to blurring regardless of main and fill durations.
Author:  atomicskil [ Fri Sep 03, 2010 11:07 am ]
Post subject:  Re: stop motion - what am I doing wrong?
thanks all, after training myself to think of my AB and UZ lights as opposite of power pack lights I got stuck there. I'll treat the Einsteins like a pack system and should be fine.

Jeff, the shutter speed is irrelevant in this photo/situation. and I've noticed that the 5d mk II does not like to sync faster than 1/160th with these lights.

TS, there are 3 einsteins on the photo, two blowing out the background, one in a beauty dish high and camera left.
Author:  Technical Support [ Fri Sep 03, 2010 11:18 am ]
Post subject:  Re: stop motion - what am I doing wrong?
atomicskil wrote:
Jeff, the shutter speed is irrelevant in this photo/situation. and I've noticed that the 5d mk II does not like to sync faster than 1/160th with these lights.


Are you using the CyberSyncs to trigger them? Even the 5DmkII should sync at 1/200 with CyberSync.


atomicskil wrote:
TS, there are 3 einsteins on the photo, two blowing out the background, one in a beauty dish high and camera left.


OK, just remember in a shot like this if the BG lights are at a higher power, they will have a longer duration, and may lead to blurring if set high enough.
Author:  atomicskil [ Fri Sep 03, 2010 12:47 pm ]
Post subject:  Re: stop motion - what am I doing wrong?
good point, TS, thanks for that reminder. I probably would have set the bkgnd to full and the key to 1/2 and still had blur. I'll dial it down and do something like 1/4 or 1/8 and 1/2 on bkgnd.

I'm not using the cyber commander. I love buff products, but can't get on board with the remotes. I'm already heavily invested in pocket wizards and aside from them making me insane with the einsteins (anxiously waiting for that fix) they are much more appropriate for my workflow that also includes dynalite packs and canon speedlights, triggering cameras and sometimes greater distance than the cyber commander can handle.
Author:  Jeff Jessee [ Fri Sep 03, 2010 12:58 pm ]
Post subject:  Re: stop motion - what am I doing wrong?
>the leg looks like it is moving from upper left to lower right. Leading edges always appear to blur more than >trailing edges.

Tech support-Can you explain this further. I would have thought that just the opposite would occur, that the leading edge would show less blur, as the blurred edge would be hidden by the leg of the same color, whereas the trailing blur would show against the white background. So maybe the leg was still moving up? Possibly the photographer could answer that.

Jeff
(I know this is off the original topic, just wanted to understand it.)
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