Freezing a dancer jumping with flash and flash duration advice

[Loose Canon]

Okay, thanks guys. Not being familiar with Nikon I was just curious how this worked with them. Your answers were about as clear as mud to me but a little more digging is shedding some light.

I'm mixing up CLS with the AWL for one thing and it looks like the ttl system determines the flash duration by power level and not by some electronic cut-off means which makes more sense to me. IGBT technology notwithstanding and considered.

I'll just keep digging!

[Manfred M]

I did test the duration at different speeds not very scientific but experimented a little just for fun my friend was wawing fast at1/1 speed wich gives a t1 one vallue at around 1/250 a little above but you get the point. Lets just say the arms where not sharp, wich i would not expect either.

That in itself is a scary statement. A test needs to be highly controlled so that you understand the impact of what you are doing.

Are you sure that this is not due to the ambient light / shutter speed? This is why I suggested that you do some test shots to see how much impact the ambient light has on the image by taking test shots without any flash. Once you know that, dial down the aperture until you get little or no ambient light impact (obviously you will have to be shooting 100% on manual).

I suspect your blurring has little to nothing to do with what is described in the link.

I think you are too fixated with the t0.5 and t0.1 points and are likely missing something more obvious. The salient point in the weblink is:

"Because of the way small flashes work (Isolated-gate bipolar transistor or IGBT power switching) the flash duration of the flash can be quite a lot faster than a standard studio type flash head or monoblock head. this means that speeds in excess of 1/25,000th of a second can be easily obtained… unfortunately at the cost of power output"

This means positioning of the lights to be close to the dancer is critical because of the low power output to achieve the shorter flash times. A common technique is to gang four flashes to increase light levels.

[dje]

Okay, thanks guys. Not being familiar with Nikon I was just curious how this worked with them. Your answers were about as clear as mud to me but a little more digging is shedding some light.

I'm mixing up CLS with the AWL for one thing and it looks like the ttl system determines the flash duration by power level and not by some electronic cut-off means which makes more sense to me. IGBT technology notwithstanding and considered.

I'll just keep digging!

Terry the mode I was referring to involves not having the flash unit itself set to manual but rather having the camera/flash unit(s) set up in Commander mode and manually setting the flash power in camera. In this mode, which I think is sometimes referred to as AWL, there is optical signalling between the camera and the flash before it goes off. I think CLS refers to this general concept of signalling whether it be for Commander mode or otherwise. This Scantips article gives more info.

In this mode, flash power seems to be controlled mainly by changing the flash duration. The camera tells the flash what duration to use, based on the shutter speed set in the camera. The idea is to have the flash emitting light only during the time the shutter is fully open to avoid any uneven exposure across the image. As the shutter speed gets quicker, the amount of time that the shutter is fully open decreases up until the max sync speed is reached. Beyond this, there is insufficient time to fire a flash satisfactorily during the shutter fully open period and high speed sync will be enabled.

Here are some measurements I did a while ago. All have Auto FP (Max sync speed) set to 1/250.

Power Full, SS 1/60 sec


Power Full, SS 1/250 sec


Power Half, SS 1/60 sec


Power Half, SS 1/250 sec


This little diagram I did a while ago for my own edification may also be of interest.

Dave

[george013]

Terry the mode I was referring to involves not having the flash unit itself set to manual but rather having the camera/flash unit(s) set up in Commander mode and manually setting the flash power in camera. In this mode, which I think is sometimes referred to as AWL, there is optical signalling between the camera and the flash before it goes off. I think CLS refers to this general concept of signalling whether it be for Commander mode or otherwise. This Scantips article gives more info.

In this mode, flash power seems to be controlled mainly by changing the flash duration. The camera tells the flash what duration to use, based on the shutter speed set in the camera. The idea is to have the flash emitting light only during the time the shutter is fully open to avoid any uneven exposure across the image. As the shutter speed gets quicker, the amount of time that the shutter is fully open decreases up until the max sync speed is reached. Beyond this, there is insufficient time to fire a flash satisfactorily during the shutter fully open period and high speed sync will be enabled.

Here are some measurements I did a while ago. All have Auto FP (Max sync speed) set to 1/250.

Power Full, SS 1/60 sec


Power Full, SS 1/250 sec


Power Half, SS 1/60 sec


Power Half, SS 1/250 sec


This little diagram I did a while ago for my own edification may also be of interest.

Dave

I remember that thread and it didn't satisfy me then and now.

Nikon determines the needed flash power(=flash duration) in not-manual mode through a pre-flash. Just before the mainflash a pre-flash is done, the received reflection of that pre-flash is used to calculate the flash power (= flash time).

In manual no pre-flash is used. The camera or the flash unit calculates the flash-power on the forehand.

George

[teigas]

That in itself is a scary statement. A test needs to be highly controlled so that you understand the impact of what you are doing.

Are you sure that this is not due to the ambient light / shutter speed? This is why I suggested that you do some test shots to see how much impact the ambient light has on the image by taking test shots without any flash. Once you know that, dial down the aperture until you get little or no ambient light impact (obviously you will have to be shooting 100% on manual).

I suspect your blurring has little to nothing to do with what is described in the link.

I think you are too fixated with the t0.5 and t0.1 points and are likely missing something more obvious. The salient point in the weblink is:

"Because of the way small flashes work (Isolated-gate bipolar transistor or IGBT power switching) the flash duration of the flash can be quite a lot faster than a standard studio type flash head or monoblock head. this means that speeds in excess of 1/25,000th of a second can be easily obtained… unfortunately at the cost of power output"

This means positioning of the lights to be close to the dancer is critical because of the low power output to achieve the shorter flash times. A common technique is to gang four flashes to increase light levels.

There was a small small amount of ambient coming in from the windows, and i did not adusjt my apature it staid om 5,6. So the picture is a little overeksposed. It checked different times and saw that 1/1 did not work, i also used the lowest power and worked my way to check, i was able to freeze it complete at several shots, but when i worked up neared 1/1 and 1/4 i could see som small blur on his arms. I also tried 1/32 not in the pictures attached and that did not show any blur. 1/4 its not so much more pixle peep blur but you see it :P

Almost dark exporure to check for ambient interferances


1/1 power hands:



1/4 power hands a little different setup:


One the lowest settings and upwards it was offcorse more sharp or really sharp so that was no problem. But had to raise the iso a little to get what i wanted at the lowest settings. The reason i did not do it 100% scientific was because it was my cousins and his child and there patient was like say are we done now can we go now, i am hungry, ooohhh this is borring. But i got a feel for what i needed to achive, and i also saw that i could manage to freeze in a jump. But the theather will for sure be a different setups space so I think i will do a test there also before we try for real.. If they allowe me..

To be sure that i have enough power i think i will borrow an einstein 640 http://www.paulcbuff.com/e640.php one of my friends brother have one he rarly uses and he said it was okey that i borrowed it for a few beers, so I think i will go with that.

[Manfred M]

Dave - I suspect that the graphs you are showing here misleading. While the x-axis is a time scale, it seems to have changed based on the different shutter speeds being used, rather than the flash duration. Each of the two sets of graphs should in fact be identical as the flash duration at full power and manual will not change at all, regardless of shutter speed. The only differences we should see might be some minor variations of output that are within the working tolerance of the graph.

The way you set up Commander Mode in your test means that you were effectively using a fairly simple Master / Slave setup, with the on-camera flash being the master and the SB500 the slave unit. CLS is simply marketing mumble jumble that masks what is happening. It is actually a fairly sophisticated system where the camera and compliant flashed communicate with each other. George is quite right. The preflash is used to set the exposure and some level of communication with each zone (up to three individual settings (Zones A, B and C on the D800) with each zone receiving specific individual power level instructions.

[Manfred M]

Teigas - you have set up the lighting properly, (I was wrong as to the cause of the blur in my previous post), but your test is still meaningless.

While I understand the images are cropped, I suspect that your subject was waving his hands fairly quickly and you seem to be much closer to the model than you would be during the actual shoot. The amount of magnification will increase the amount of blur as you get closer and closer to the subject. Get further away, as you will be when you are getting the dancer's full body in the frame, this motion will be less of a factor.

The second issue is that you are not doing a like to like comparison with the two motion shots you are showing. Look at the mechanics of the two shots. The one at full power were taken just as they were coming up the sides of your model, i.e. probably close to maximum acceleration / velocity, so also likely where the maximum blur would occur.

Your second shot shows the arms in the totally extended position over your subject's head. Speed of the hands in that position would be close to zero, so while the power level of the flash may have had a minor impact, the largest impact would be due to the arms being at the top of the arc just before or after a directional change. A valid test would have been to take the two pictures with the arms at the same speed and position of the arc. If I were taking the picture, I would want the arms in a position of little or no motion (this is what I was suggesting you do when I said you should be taking the shot at the top of the jump; little or no motion to stop).

I believe the Einsteins are capable of some very short flash durations. Terry (Loose Canon) has done some amazing stop action shots with his Einsteins and I own four of these heads, but tend to shoot stationary subjects. I believe Jaroslav Wieczorkiewicz uses them for his fantastic milk shots. http://blog.aurumlight.com/

You will have a maximum light output that is 10 time higher than the SB900. What kind of modifiers do you have available to go on that light?

[Loose Canon]

Dave I saw that article while I was digging around and it helped me understand Nikon nomenclature a little better but still didn’t address what I thought you were saying. I think I must have misunderstood something in the interpretation.

What I think you are talking about here is the usual IGBT (or maybe in some cases thyristor) operational power interruption of modern speedlights. For whatever reason I either led myself, or was led to believe that what you were saying was something different or possibly proprietary to Nikon and it’s not. My mistake!

Flash duration is determined by flash power level and that is pretty much that. The “much quicker” cut-off you are describing of Nikon speedlights is simply the IGBT technology at work. This basically interrupts power to the speedlight after a given duration, which is dependent on the power output, which stops the light tail and saves the unused charge for the next pop. This in contrast to the majority of studio lights, which do not use this technology and must discharge the entire charge with each flash discharge. In fact, the majority of today’s speedlights work with this technology. Not just Nikon and that’s where I think I misunderstood.




Teigas,

It looks to me that you are well on your way and understand what Manfred has been talking about. But he makes a good point regarding the speed of motion you are comparing with your test shots. You may very well find that you may have to adjust your thinking on the fly at the shoot. I’m betting your dancer will move a lot faster than these test shots. Further, if you want to catch the dancer mid-air you are going to only have a brief moment to do so and with arms flailing! But I also think you have a good idea of what you will need to do to make that happen to stop the action.

The Einstein, as of at least a couple of years ago, had the fastest studio flash duration on the market. I don’t know at present because I haven’t looked recently. It will certainly do what you want and will give you more light output to play with as well compared to a speedlight. Only you can determine if one will be enough to light your scene the way you want it. If you are going to use just one I would suggest you have some reflectors/stands/assistants to hold said available to help pump some light back into the scene if desired.

I would suggest you use the Einstein in its “Action” mode to start. Then once you determine what you need from it you might switch over and try its “Constant Color” mode if you think that mode can provide the durations you need. You may or may not notice any color differences at this point since you will be looking more toward another aspect (stopping the motion).

If you are not already aware, something to keep in mind? If you are using more than one light and have them set at different power levels, the light set at the highest power level will determine the stopping potential. So you have to make sure that light’s power level is such that it will do the stopping. I know that sounds obvious, but it isn’t always to a lot of folks.

[dje]

Dave - I suspect that the graphs you are showing here misleading. While the x-axis is a time scale, it seems to have changed based on the different shutter speeds being used, rather than the flash duration. Each of the two sets of graphs should in fact be identical as the flash duration at full power and manual will not change at all, regardless of shutter speed. The only differences we should see might be some minor variations of output that are within the working tolerance of the graph.

Manfred the time base setting of the Oscilloscope I used is shown in the bottom right hand corner of each screenshot. It is 1 msec per division in each of the four cases. The voltage and ms readings shown on the mid right hand side of each shot are my summary readings that I added into the jpegs.

The actual power level will be different in each case !

Dave

[dje]

Dave I saw that article while I was digging around and it helped me understand Nikon nomenclature a little better but still didn’t address what I thought you were saying. I think I must have misunderstood something in the interpretation.

What I think you are talking about here is the usual IGBT (or maybe in some cases thyristor) operational power interruption of modern speedlights. For whatever reason I either led myself, or was led to believe that what you were saying was something different or possibly proprietary to Nikon and it’s not. My mistake!

Flash duration is determined by flash power level and that is pretty much that. The “much quicker” cut-off you are describing of Nikon speedlights is simply the IGBT technology at work. This basically interrupts power to the speedlight after a given duration, which is dependent on the power output, which stops the light tail and saves the unused charge for the next pop. This in contrast to the majority of studio lights, which do not use this technology and must discharge the entire charge with each flash discharge. In fact, the majority of today’s speedlights work with this technology.

Terry it seems our stars are now aligned !

Dave

[William W]

. . . I am going to try to freeze a dancer when doing a leap or a dance jump . . . I want to use flash light to achieve this since its indoor and a dark place . . .

This summary is what I consider to be the main points for your consideration. Some points have been mentioned but not spelled out this way:

1. These are all GUIDELINES as to where the LIMITS will apply. Guidelines are not facts and that’s important to remember.

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2. Neither Shutter Speed nor Flash ‘speed’ (duration) actually freezes motion, what we want to know is the ‘speed’ necessary to make the Final Image appear as though Subject Motion has been arrested.

*

3. The ‘speed’ which necessary to arrest motion is either Shutter Speed - OR - Flash 'Speed' - OR - the slower of the two if both make a viable exposure.

The first part of that sentence is an important concept, because what we know about Shutter Speeds for Ambient Light, we can apply to Flash ‘speeds’ (duration) for Flash Exposures.

The second part of that sentence in an important concept because it goes to the understanding of why, (if one is using Flash to arrest motion), the Ambient Exposure must be well under the Flash Exposure.

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4. The ‘speed’ necessary to arrest motion depends upon:

a) the speed of the motion – the faster the speed of the Subject, the faster the ‘speed’ to arrest
b) the direction of the motion relative to the lens’s axis – the more transverse the motion, the faster the ‘speed’ to arrest
c) the distance from Camera to the Subject - the closer to the camera, the faster the ‘speed’ to arrest
d) the Focal Length of Lens used - the longer the FL of the lens, the faster ‘speed’ to arrest
e) the crop in post production – the tighter the crop, the faster the ‘speed’ to arrest
f) the viewing distance of the image – the closer the viewing distance, the faster ‘speed’ to arrest

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5. The (QUICK) decay RATE and (QUICK) decay TIME of the Flash is a very important consideration when using flash ‘speed’ to arrest Subject Motion - that’s why “Speedlites” generally have a big advantage over (more powerful) Studio Flash Heads.

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6. Timing of the shot is usually ALWAYS important, irrespective of how safe the ‘speed’ is that the Photographer uses to arrest Subject Motion.

Importantly, in any RHYTHMIC MOTION there will be a point of LEAST SUBJECT MOTION.

A Dancer’s Leap is an example of Rhythmic Motion.

In a Dancer’s Leap the point of Least Subject Motion is almost always at the full extension of the leap: this is so because the dancer seeks to create the illusion of “floating in mid-air” à la Nureyev or Li Cunxin.

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7. A Subject may be (and probably is) moving at different speeds and in different directions, simultaneously.

In this case the Photographer needs to compromise and seek to arrest the Subject Motion which is the most relevant to The Shot.

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8. High Speed Flash Sync is usually NEVER your friend if you want to freeze Subject Motion.

***

Notes and examples to the key points above:

Points#1 and#3 An example of how knowledge can be applied.

I know that I require 1/1250th second for a crisp shot of a National Swimmer at the Backstroke Start when shooting about ¾ Transverse Motion and the swimmer occupies nearly all the frame, here (swimmer in blue cap):



So I can reckon without any research that is akin to an accomplished Dancer making a Leap from a crouched position; if the dancer is at full transverse motion then I can reckon I should bump to 1/2000th second to be safe; if the dancer is making a running leap and at full transverse motion then maybe I should bump to 1/4000th second, to be safe – note these ‘speeds’ to be safe are either the camera's Shutter Speed or the Flash's ‘speed’ (duration).

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Point #3 – It is really important to understand the effect of the AMBIENT EXPOSURE when using flash.

To begin to be safe (i.e. to likely avoid any Subject Movement Blur because of the Ambient Exposure) the Ambient Exposure should be about 5 Stops UNDER the Flash Exposure: suffice to state the more the Ambient is under the better.

BEWARE of this trap which is often encountered:

Let’s say for the sake of discussion that the gym is dark and the ‘correct’ Ambient Exposure for the Dancer would be: F/4 @ 1/200s @ ISO 3200.

Let’s say you’re using your Flash at ¼ Output (that’s a ‘speed’ of 1/2550th second as quoted in the OP) and the “correct” Flash Exposure is: F/11 @ 1/200s @ ISO 800.

Then that’s all fine and dandy because you are thinking to yourself, "the Ambient Exposure is 5 Stops under the Flash Exposure and there likely will not be any Subject Motion Blur noticeable caused the Ambient Exposure."

The main two traps I have seen novices fall into is, forgetting about the Ambient Exposure and then later thinking:

a) “It would be nice to use a lower ISO to make the shot crisper with less noise” . . . “Ok, so I will use ISO 400.”

or

b) “Gee it would look better it I moved the Flash Head back a bit to give a broader light”

But to accommodate either of those changes, one needs to OPEN UP the APERTURE to keep the correct Flash Exposure, which of course allows more Ambient Exposure and thus more possibility of Subject Motion Blur.

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Point #4 Have a close look at points: 4c), 4d) and 4e) and note that those three can be all rolled into FRAMING of the Shot – the tighter the Framing of the Final Image the faster the ‘speed’ to arrest.

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Point #6:



Backdrop of Li Cunxin in 'action' - Image of Li Cunxin giving Address.

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Point #7 Accommodating blur and adjusting for accommodation:

Have a close look at swimmer in the image above and note that I pulled that shot at 1/1250th second.

Now look at the image below. This is the same swimmer but because of a Lighting Bank failure I needed to use a faster lens (faster than F/2.8) and also a slower Shutter Speed (1/800th second) to make the Shot.

To accommodate the slower Shutter Speed, I moved up the pool and made the Camera Viewpoint at a sharper angle to the swimmer (more head on) so that Subject Motion was LESS transverse to the Lens’s Axis.

I also framed looser (the swimmer takes up less image real-estate).

These two actions meant that I could use a SLOWER shutter speed than I would normally would use and in the Final Image I would still likely get little or no Subject Motion Blur of that swimmer at that peak of movement .

You might notice that the swimmer closest to the camera has blurred arms, even though they are out of focus the blur is attributed to the downward movement of the arms – which is transverse, i.e. directly at 90° to the Lens’s Axis.



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So you can apply this knowledge and these points as you practice your “Leaping Dancer” captured by Flash:

For examples:

- whilst you might have a flash ‘speed’ fast enough to arrest the motion of the body in the leap: if the Dancer has their arms flaying about then those arms might still appear to be blurred.

- you might move your camera to capture more transverse motion and for the same type of leap and using the same Flash 'speed', see blur in the Final Image when you didn't see blur before.

- you might move closer the Subject or Zoom in on the Subject and for the same type of leap and using the same flash 'speed', see blur in the Final Image, when you didn't see blur before.

- you might crop the image tighter and for the same type of leap and using the same flash 'speed', see blur in the Final Image, when you didn't see blur before.

etc . . .


WW

All Images © AJ Group Pty Ltd Aust 1996~2015, WMW 1965~1996

[george013]

Well said.

I always formulate in my own ways. Maybe this will help others to understand what's happening.

A flash photo always exist out of 2 exposures: 1 with existing light and within that 1 with flash light. It's the same you say.

The motion you want to capture can be expressed as a speed of something in the image expressed relative to the image sizes. That can be the sensor, 100%, or a cropped print.

May I add 1 more consideration. The background A dark background may eliminate the motion blur due to the existing light part more than a bright background. I think.

George

[Manfred M]

Well said.

I always formulate in my own ways. Maybe this will help others to understand what's happening.

A flash photo always exist out of 2 exposures: 1 with existing light and within that 1 with flash light. It's the same you say.

The motion you want to capture can be expressed as a speed of something in the image expressed relative to the image sizes. That can be the sensor, 100%, or a cropped print.

May I add 1 more consideration. The background A dark background may eliminate the motion blur due to the existing light part more than a bright background. I think.

George

I would word thing slightly differently George. In flash photography there are THREE sources of light that concern the photographer.

1. The ambient light;

2. The direct light from the flash that falls on the subject; and

3. The indirect light of the flash bouncing off nearby objects, especially the floor, walls and ceiling. You are right about the darker background as it will help absorb both the ambient and indirect light from the flash. Another way to accomplish this is to shoot in a room that is large enough to have the flash falloff darken the space.

The third reason is why we use grids on the light modifiers to direct the light and flags to ensure that stray light does not hit the subject.

[george013]

I would word thing slightly differently George. In flash photography there are THREE sources of light that concern the photographer.

1. The ambient light;

2. The direct light from the flash that falls on the subject; and

3. The indirect light of the flash bouncing off nearby objects, especially the floor, walls and ceiling. You are right about the darker background as it will help absorb both the ambient and indirect light from the flash. Another way to accomplish this is to shoot in a room that is large enough to have the flash falloff darken the space.

The third reason is why we use grids on the light modifiers to direct the light and flags to ensure that stray light does not hit the subject.

It's not about light. It's about exposure. When you use a flash you make 2 exposures in one image. One exposure with let's say 1/1000s with flash and one with 1/125s with ambient light.
When I taught my daughter and her girlfriend some basics of photography, they showed me next picture they made. I think it's fascinating and shows what happens when you use flash. The second curtain pictures are another example of it.

There's no exif in the picture and I must say I still don't fully understand what happened.


George

[Shadowman]

It's not about light. It's about exposure. When you use a flash you make 2 exposures in one image. One exposure with let's say 1/1000s with flash and one with 1/125s with ambient light.
When I taught my daughter and her girlfriend some basics of photography, they showed me next picture they made. I think it's fascinating and shows what happens when you use flash. The second curtain pictures are another example of it.

There's no exif in the picture and I must say I still don't fully understand what happened.


George

That's a nice effect they made, similar to shooting long exposure with a bright light source somewhere near midground and having the subject move slowly into or out of the frame.

[Loose Canon]

It's not about light. It's about exposure. When you use a flash you make 2 exposures in one image.

And:

A flash photo always exist out of 2 exposures: 1 with existing light and within that 1 with flash light.

Interesting concept and one I don’t completely understand, but I’ve misunderstood a couple of things already in this thread! If it’s not about light, or in other words without light, nothing in the shot is exposed.

The other reason I’m not getting this is because in a studio setting, or for freezing motion with flash, which this thread is about, ambient light must not play a role in the exposure so must be taken out of the equation to the point that it doesn’t. Manfred and Bill have addressed this and Teigas has demonstrated with his black frames that he too, understands this.

There's no exif in the picture and I must say I still don't fully understand what happened.

George I’ve run into this phenom like what is happening in Daughter’s shot before using “long’ exposures and second curtain flash.

Without getting too overly windy about it, with a long exposure a person can move through the frame without registering if the exposure is long enough or if the person moves fast enough, or both. In a word, in the accumulated light gathering of a long exposure, the person does not reflect enough light for long enough, or over enough pixels in the frame to be exposed.

If this shot is a “long” exposure with second curtain (and it looks like it is), one would expect to see motion trails before the flash fired. It looks like the person was either moving too fast to register motion trails or the exposure was too long to register, or both. Then, when the flash fired the power level was too low to fully expose them. There was not enough flash to reflect off them. This is why the ghosting and apparent transparency of the person in some areas. Some areas got enough light to be exposed enough to appear “solid” and some were not.

[teigas]

Teigas - you have set up the lighting properly, (I was wrong as to the cause of the blur in my previous post), but your test is still meaningless.

While I understand the images are cropped, I suspect that your subject was waving his hands fairly quickly and you seem to be much closer to the model than you would be during the actual shoot. The amount of magnification will increase the amount of blur as you get closer and closer to the subject. Get further away, as you will be when you are getting the dancer's full body in the frame, this motion will be less of a factor.

The second issue is that you are not doing a like to like comparison with the two motion shots you are showing. Look at the mechanics of the two shots. The one at full power were taken just as they were coming up the sides of your model, i.e. probably close to maximum acceleration / velocity, so also likely where the maximum blur would occur.

Your second shot shows the arms in the totally extended position over your subject's head. Speed of the hands in that position would be close to zero, so while the power level of the flash may have had a minor impact, the largest impact would be due to the arms being at the top of the arc just before or after a directional change. A valid test would have been to take the two pictures with the arms at the same speed and position of the arc. If I were taking the picture, I would want the arms in a position of little or no motion (this is what I was suggesting you do when I said you should be taking the shot at the top of the jump; little or no motion to stop).

I believe the Einsteins are capable of some very short flash durations. Terry (Loose Canon) has done some amazing stop action shots with his Einsteins and I own four of these heads, but tend to shoot stationary subjects. I believe Jaroslav Wieczorkiewicz uses them for his fantastic milk shots. http://blog.aurumlight.com/

You will have a maximum light output that is 10 time higher than the SB900. What kind of modifiers do you have available to go on that light?

I am not sure i belive he has a farly not so big octa softboks for it and also a small strip boxs.. So i might just go with the big octa, and try to see, and use it as a main light. I am not sure what he really have for it, I have to see tomorrow when i pick it up.

[teigas]

Thank you for the insight

[teigas]

Thanks for all the help. Now i just have to test it out and try. I think i will start with the einstein as a main light, and if i need some more lights i will try the speedlights and add some in on a lower output for fill or seperation.

I am not an expert at flash, and light placements. (but i guess its not a correct answear on that because it depens where , when, light conditions, on what you want to achive) that is also why I want to test and learn, the only way to get better is to try new things and different technics.

As previosly mentioned i also perhaps want to try out rear curtain sync while i am at it.
I understand the concept, and have tested it out slightly but only in a small space and with no black bakcround.

Am i right that the concept is that you need some sort of ambient light in the first part of the imgage (if everything was dark the camera would not catch anything) to light up the trail? And then place a flace at the end, so she gets frozen by the flash at the end.

Like in this picture he has some lights pointed towards the dress i think or a little on the bacground and then freezes her with flash at the end, or tryes to (not complete sharp) found this example on google.
http://3zgehi1uaxi23dphbrgqa50r6z.wp...9.54.28-AM.png

I tried to do this in the small gymnastic hall i tested out the duration and freeze stuff. Would it been better with a black backround and some more ambient or smaller for the start perhaps... I think I just want to test this out in the theather also for fun..
Her is a short test on my goddaughter.


I also tried to play with rpt one day this is myself, that concept i understand the basics of.


THis is my and a friend going a little overboard with it :P

[Loose Canon]

As previosly mentioned i also perhaps want to try out rear curtain sync while i am at it.
I understand the concept, and have tested it out slightly but only in a small space and with no black bakcround.

Am i right that the concept is that you need some sort of ambient light in the first part of the imgage (if everything was dark the camera would not catch anything) to light up the trail? And then place a flace at the end, so she gets frozen by the flash at the end.

Yes you are right Teigas. And the brighter the ambient, the brighter the motion trails. The flash then freezes the moving subject at the end of the exposure. The Einstein you are going to use is not capable of automated second (rear) curtain firing so you will have to use the speedlights for this.

Here is an example of a "long" exposure (0.4 second shutter). I simply rolled the truck/car across the surface at about the same time I started the exposure. Got the motion trails because of the ambient light. The flash fired at the end of the exposure freezing the truck/car.



And here is one using a wooden toothpick bounced off a surface. When the toothpick bounced into the air I started the exposure and got the motion trail. The flash froze the toothpick and you can see it frozen toward the end of the motion trail.



Here is the set-up I used for the toothpick shot. The two lights with the silver reflectors provided the continuous “ambient” light, and the softbox at the top is the flash.



I think a black background would be better but it is not necessary. In your example you did not expose your subject enough so she appears transparent. Post #36 gives a short explanation of this.