Long exposure portrait.

Phil Young

Phil Young

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I have a shoot tomorrow and have a cool idea to set a 45s exposure with my 10 stop and somewhere close to the end of the shot, pop my subject in there, flash them with a shoot through brolly modified flash and then get the subject out again, with a means of getting a subject evenly lit with the BG.

I'm at work right now so can't test it but in theory the above will work right??
 
it could work, but I suspect at 45 seconds you'll have ghosting from your subject, which may be what you want.

It also begs the question what are you trying to achieve?
 
Would a couple of seconds of exposure not achieve same? Without the risk of a blur of them popping into the scene? Get them to hold their breath, anyone can do this and keep still for 2-3 seconds.
 
boyfalldown said:
it could work, but I suspect at 45 seconds you'll have ghosting from your subject, which may be what you want.

It also begs the question what are you trying to achieve?
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The normal look from a long exposure, smooth silky clouds but then the well lit, sharp subject of a normal portrait.

If it's cloudy I might be able to get away with a f11-16 60s exposure but don't really want to stop down too much...

I'll be having a go anyway and see but any idea of flash settings for a 60s exposure would be good. Assume a starting point of one flash, full power is the way to go...
 
Cagey75 said:
Would a couple of seconds of exposure not achieve same? Without the risk of a blur of them popping into the scene? Get them to hold their breath, anyone can do this and keep still for 2-3 seconds.
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Nope. I need at least 45s for the clouds to show good movement and then I need the portrait to be sharp and well lit, enough to stand out from the BG.
 
Ah, I see. Well, I'm not the best with lights, but if the flash is set to a low output, i think it might work. I imagine it's going to take more than a few attempts of trial and error to get right though.
 
Phil Young said:
The normal look from a long exposure, smooth silky clouds but then the well lit, sharp subject of a normal portrait.

If it's cloudy I might be able to get away with a f11-16 60s exposure but don't really want to stop down too much...

I'll be having a go anyway and see but any idea of flash settings for a 60s exposure would be good. Assume a starting point of one flash, full power is the way to go...
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I would imagine it would work, though I suspect you'd have to play with the flash power a lot. TBH I wouldn't know a good starting point although I suspect you may want a good deal of power though a 10 stopper and a brolly.

I'd also be inclined to leave her in play for the duration of the exposure, and use the flash to freeze her. I think you'd get blurs if you moved her in or out
 
Sounds like you would like to try the same method as used in nightclub photography (shutter kept open for a few sections to get the streaks of light and then a final flash to capture the people). Would be interesting to see the end result.
 
I can see what your going for but I suspect it will be hard to achieve as I'm not sure but suspect you'll have to be really powerful on the flash to even get the person to appear in the exposure through the ND, and as said above you'll likely end up with a ghost image rather than a totally solid person even if the flash does allow the person to be picked up through the filter...although I've not got the photoshop skills to do it I suspect it's going to be far easier to take two photo's and then merge them together :thinking:
 
Phil Young said:
I have a shoot tomorrow and have a cool idea to set a 45s exposure with my 10 stop and somewhere close to the end of the shot, pop my subject in there, flash them with a shoot through brolly modified flash and then get the subject out again, with a means of getting a subject evenly lit with the BG.

I'm at work right now so can't test it but in theory the above will work right??
Click to expand...

You'll need the subject in position from the start to avoid ghosting - and a nuclear powered flash gun.

Basically, no chance through a ten stopper. You'd need one thousand normal power flashes to balance the ambient exposure. Or 1000 flash guns - same difference.
 
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I can't help on the lighting front but I tried a similar concept without lights in my last session of long exposures (tried for a silhoutte of self in scene).

My camera was set at F11 with the 10 stopper on, I fired the shutter and ran into the scene. Stood as still as I could for 60 or so secs, jumped out of the scene and stopped the exposure.

the result was crap to say the least. The outline of my body was perfectly defined without any ghosting however I was relatively see through to say the least.
I thought standing for a minute might be enough but clearly it wasn't. Either that or shooting into the sun changes the dynamics of the shot.

Will be interesting to see what you come up with though.
 
HoppyUK said:
You'll need the subject in position from the start to avoid ghosting - and a nuclear powered flash gun.

Basically, no chance through a ten stopper. You'd need one thousand normal power flashes to balance the ambient exposure. Or 1000 flash guns - same difference.
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I can put 3 flashes through one brolly on full power and then move them out of the frame.

That should do it...?
 
Phil Young said:
I can put 3 flashes through one brolly on full power and then move them out of the frame.

That should do it...?
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No.

Think about it - the ten stops filter reduces the whole exposure by a factor of 1024, so every component of the exposure must be increased by that level.

You could do it with continuous light. If that's bright enough to balance with the ambient for a normal exposure, it will be the same through the filter and will automatically receive 1000x the normal exposure through the long shutter speed.
 
HoppyUK said:
No.

Think about it - the ten stops filter reduces the whole exposure by a factor of 1024, so every component of the exposure must be increased by that level.

You could do it with continuous light. If that's bright enough to balance with the ambient for a normal exposure, it will be the same through the filter and will automatically receive 1000x the normal exposure through the long shutter speed.
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Are we on the same page?

In my head... I light my subject with flash and then the background is lit with ambient.

I don't expect or want to get it 100% balanced but I can't see why that can't be done with flash??
 
Phil Young said:
Are we on the same page?

In my head... I light my subject with flash and then the background is lit with ambient.

I don't expect or want to get it 100% balanced but I can't see why that can't be done with flash??
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The point people are making is that with an ND10 on your camera next to nothing from the flash will get through. The earlier suggestion of continuous lighting lighting just the person is probably the best way - or two images as another suggested.

Still - I'd like to hear how it actually went!
 
Phil Young said:
Are we on the same page?

In my head... I light my subject with flash and then the background is lit with ambient.

I don't expect or want to get it 100% balanced but I can't see why that can't be done with flash??
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If the flash is fired when the ten-stopper is in place, then it's brightness will be reduced by 1000x.
 
Phil Young said:
Are we on the same page?

In my head... I light my subject with flash and then the background is lit with ambient.

I don't expect or want to get it 100% balanced but I can't see why that can't be done with flash??
Click to expand...

I suspect what hoppy is saying is you'll never generate enough power from the flashes. Why not use a 6 stop instead?
 
boyfalldown said:
I suspect what hoppy is saying is you'll never generate enough power from the flashes. Why not use a 6 stop instead?
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Wont get a long enough shutter but it doesn't matter since I can always increase ISO.

3 flashes fired together, on full power will surely get through...?

I'll gave a little test on a chair or something before heading out to see if I'll be able to get the effect or not.
 
Phil Young said:
Wont get a long enough shutter but it doesn't matter since I can always increase ISO.
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:thinking:

3 flashes fired together, on full power will surely get through...?
I'll gave a little test on a chair or something before heading out to see if I'll be able to get the effect or not.
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Three flash guns will give you 1.5 stops brighter exposure than one. You need ten stops.

2, 4, 8, 16, 32, 64, 112, 256, 512, 1064 = ten stops.

Easy to test - set the flash up for correct exposure, then put the filter on and see what you get. Total darkness :thumbsdown:
 
Phil Young said:
We shall see... perhaps I could get away with firing more than once.
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Yes - fire it 1000 times. Not practical.

Your only chance would be to wait until the ambient light level drops enough to give sufficient length of exposure with maybe a 3-stops ND. Then fire the flash 8 times. Every stop doubles the number of flashes required, as per the scale above
 
maybe, but I think then your going to have issues with subject movement. Don't forget your flashes are going to need 2-4 seconds to recycle each time. I would tone the strength of the ND down
 
HoppyUK said:
:thinking:

Three flash guns will give you 1.5 stops brighter exposure than one. You need ten stops.

2, 4, 8, 16, 32, 64, 112, 256, 512, 1064 = ten stops.

Easy to test - set the flash up for correct exposure, then put the filter on and see what you get. Total darkness :thumbsdown:
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Eh, I'll just pop the filer on manual mode, f16 ISO 100, 45s and then fire the flashes into a chair before moving it. If it's really dark then I'll remove the umbrella and it's it's still really dark then I just won't bother...
 
HoppyUK said:
Yes - fire it 1000 times. Not practical.

Your only chance would be to wait until the ambient light level drops enough to give sufficient length of exposure with maybe a 3-stops ND. Then fire the flash 8 times. Every stop doubles the number of flashes required, as per the scale above
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What about 3 fired consecutively??

So 3 full flashes within a range of say... would that be better than firing all together??
 
Phil Young said:
What about 3 fired consecutively??

So 3 full flashes within a range of say... would that be better than firing all together??
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Phil, you seem to be thinking that a ten-stops ND filter treats flash light differently to ambient light. It does not.

With ambient light, if the normal exposure is 1/1000sec then increasing shutter speed to 1 second delivers 1000 times the exposure, ie ten stops. Or 1/500sec to 2 seconds, 1/250sec to 4 seconds, and so on.

To do the same with flash and increase the exposure ten stops, you either need to fire the flash 1000 times or have 1000 flash guns fire at once.
 
HoppyUK said:
Phil, you seem to be thinking that a ten-stops ND filter treats flash light differently to ambient light. It does not.

With ambient light, if the normal exposure is 1/1000sec then increasing shutter speed to 1 second delivers 1000 times the exposure, ie ten stops. Or 1/500sec to 2 seconds, 1/250sec to 4 seconds, and so on.

To do the same with flash and increase the exposure ten stops, you either need to fire the flash 1000 times or have 1000 flash guns fire at once.
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I don't think it treats any light differently, you just through me by saying it's only 1.5 stops more light than one by adding an additional two flashes that's all. I'd have thought it to be 3x the amount of light but that's probably just my silly thinking :)
 
Phil Young said:
I don't think it treats any light differently, you just through me by saying it's only 1.5 stops more light than one by adding an additional two flashes that's all. I'd have thought it to be 3x the amount of light but that's probably just my silly thinking :)
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It is 3x the light. Which is 1.5 stops more.

This is basic exposure stuff - one stop difference is half (or double) the amount of light, ie 2x, 4x, 8x, 16x, 32x etc.
 
Phil Young said:
Richard I just know what makes a good shot, I have no idea about all this light stuff and the figures between them :)
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Yes, I understand what you're trying to do, and it would make a good shot - but just not possible the way you're planning.

Sorry to be blunt, but what you're saying above is that you don't understand the fundamentals of exposure and you will not get far without that. Google the Exposure Triangle and get a proper grip on the doubling/halving principle that underpins everything. Try this tutorial by Pookeyhead http://www.talkphotography.co.uk/forums/showthread.php?t=440126 which also covers the inverse square law that rules everything to do with flash.

markmullen said:
If, as I would suggest, you end up going down the two frames route and comp them together don't forget to white balance them up, your 10 stop will likely have a very different colour temperature to the flash you use for the single portrait shot.
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This is Phil's best bet.
 
I can only see 2 exposures as the answer, I've done similar shots for weddings at night (star shots with clouds etc)
IMHO, it will also be a lot easier as I don't think it will work otherwise as has been stated. Just do 2 exposures, meter for the subject, then meter the long exposure then compose them together, if you need help in photoshop etc then I'm happy to do a guide :)
 
Phil Young said:
Nope. I need at least 45s for the clouds to show good movement and then I need the portrait to be sharp and well lit, enough to stand out from the BG.
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No need for 45s and a 10 stop, just get a windy day with low clouds and a 6 stop?
 
That'll only need 64 flashes.
 
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