Studio Flash for low key images

Morph3ous

Morph3ous

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I'm having a play with my new twin head studio flash set up from Lencarta, and I have to say I'm really impressed with the kit. Very pleased I decided to go with this instead of speedlights.

I don't think these heads have High Speed Sync and so I have to keep the shutter speed down below 1/250 otherwise I catch the shutter curtain.
I'm trying to achieve those 'low key' style images, where the off camera flash comes across the subject lighting only one side leaving the rest in shadow, but I'm struggling to achieve it with my powerful studio flashes, even when they're dialed down to minimum. How can such an image be captured when you cannot use HSS?

When I alter the aperture, making it smaller, all this seems to do is reduce the exposure of the whole image, not keep the details in the 'flash lit' side of the subject.
 
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Move the lighting back, distance would help
I did this not long ago with a single soft box, 1/125 f8

http://www.pbase.com/byker28i/image/159465857

I had to keep the light source back and dialled down to soften it and so not to light the simple dark thick cotton backdrop
 
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It isn't about the quantity of the light at all, it's about the quality of the light, or in other words the way that you control the light. If it was about quantity, you could set the ISO as low as possible, set the flash power as low as possible, use a smaller aperture, fit a ND gel over the lights, a ND filter over the lens or all of the above, but none of these would be the slightest help with this. And the shutter speed is irrelevant to what you're doing too.

It's about controlling the light so that it only reaches where you want it to reach, it's as simple as that.
Keep it off the background by having the subject as far away as possible from the background and make sure that no light reaches the background. You can clearly see, in the first example, that the flash head is behind the subject and facing away from the background - that's why the background has photographed as black and only the front of the subject is lit. Black walls can help in a small space because they prevent unwanted light bouncing around, but they're just a nice-to-have.

You can see where the light is in the second example too, it's above and in front, which means that very little light is travelling towards the background.
Sorry, but the advice to have the light source further back is wrong. The light needs to be very close.. The closer the light, the greater the effect of the inverse square law and the less light will reach the background.

FWIW, a honeycomb fitted to the softbox would help too.
 
What Garry said but I'm curious as to what settings the op is using on the head and camera, I'm assuming he has a Smartflash 2 200 which goes down to 6w which shouldn't be too much power at all...
 
I tried this few times and always failed until I got some grids for my soft boxes to control the spill onto the background. As others have said, if you are still getting the images too bright move the lights further away from your subject. I had no real issues with the lights turned down, its more a problem of controlling where the light goes rather than how much of it there was.
 
As Garry said, it's about quality of the light, not the quantity. The fact that those images look dark and moody is because the light has been controlled to fall where it is wanted, and not where it isn't wanted. Preventing spill and light bouncing around reflected off walls, furnishings, whatever. The overall exposure level is irrelevant to that, and in fact it's probably easier to keep the flash quite bright in order to reduce any influence from ambient light - normal room lighting, daylight coming through curtains etc.
 
HoppyUK said:
As Garry said, it's about quality of the light, not the quantity. The fact that those images look dark and moody is because the light has been controlled to fall where it is wanted, and not where it isn't wanted. Preventing spill and light bouncing around reflected off walls, furnishings, whatever. The overall exposure level is irrelevant to that, and in fact it's probably easier to keep the flash quite bright in order to reduce any influence from ambient light - normal room lighting, daylight coming through curtains etc.
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Good point
Tunbridge said:
I tried this few times and always failed until I got some grids for my soft boxes to control the spill onto the background.
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Honeycombs do help, and I think that everyone who has seen me working will know that I use them a lot - BUT it can be done without them, and I did this type of lighting for years before honeycombs were invented. A good alternative is to flag the lights, and Cinefoil (blackwrap) is even better than honeycombs for this.
Tunbridge said:
As others have said, if you are still getting the images too bright move the lights further away from your subject.
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I repeat, the opposite is true - move the lights closer, not further away.
 
Move subject closer to light source & further away from background - What garry & Hoppy are talking about is inverse square law of light fall-off - there are some great examples on You tube showing this effect..
 
Garry Edwards said:
I repeat, the opposite is true - move the lights closer, not further away.
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You're right but you know why people are suggesting to move the light further away if it's too bright and to be fair if the op is finding it too bright moving it closer is going to make things worse.

I'm still curious to find out why the op has that issue as 6w at minimum power shouldn't be a problem even in a very small environment.
 
The op is finding it too bright on the background not the subject as he says closing that aperture reduces the whole exposure. The only way to reduce the light on the background is to flag it off or increase the relative difference between the subject and background which is done by moving the light closer to the subject, or moving the light and the subject away from the background.

Zakk Arias has some good guides on lighting and his one light tutorials explain flash exposure excellently.
 
Thanks very much for the replies.

I've been using just one softbox, with the flash head at its minimum power (5.0 on my wavesync) the shutter at 1/125, ISO 100 and the aperture at 6.3 ish. The room I'm working in isn't too big, so I think from what's been said its the spill out across the background etc that's causing the problem. I'm using an 85x85 softbox which is big in the room. I cannot fit a softbox to this model so this isn't an option moving forward.

I'll have a look at the suggested links [emoji4]
 
You need to study the inverse square law and flash exposure more. The important part of this here is if you double the distance between subject and light source you lose two stops of light. If your'e shooting in a typical small room say 15' long, if your light is 6' from your subject and background is 3' behind subject then the background gets only around 1 stop less light than the subject and will be pretty well lit. If you move the light closer to the subject so light is 3 feet from subject the background now gets 2 stops less light as the the distance between the background and the light is now double the distance between the subject and the light. If you then move the light and the subject a further 6 feet from the wall so you now have 3' between subject and light and 12' between background and light you'll get 4 stops less light on the background. At this point your pretty much guaranteed to have a black background.

Now size of room and modifier will influence in other ways due to light bouncing round but light always falls off at the same rate and if you keep that in mind you can control the lights exposure better. Here's a fun video on inverse square law by Karl Taylor since I couldn't find the other clip I was thinking of and Onelight is a paid for tutorial.


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This assumes you have set your cameras exposure to not allow any ambient light in so it does not affect the background exposure.
 
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CraigDHD said:
You need to study the inverse square law and flash exposure more. The important part of this here is if you double the distance between subject and light source you lose two stops of light. If your'e shooting in a typical small room say 15' long, if your light is 6' from your subject and background is 3' behind subject then the background gets only around 1 stop less light than the subject and will be pretty well lit. If you move the light closer to the subject so light is 3 feet from subject the background now gets 2 stops less light as the the distance between the background and the light is now double the distance between the subject and the light. If you then move the light and the subject a further 6 feet from the wall so you now have 3' between subject and light and 12' between background and light you'll get 4 stops less light on the background. At this point your pretty much guaranteed to have a black background.

Now size of room and modifier will influence in other ways due to light bouncing round but light always falls off at the same rate and if you keep that in mind you can control the lights exposure better. Here's a fun video on inverse square law by Karl Taylor since I couldn't find the other clip I was thinking of and Onelight is a paid for tutorial.


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This assumes you have set your cameras exposure to not allow any ambient light in so it does not affect the background exposure.
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That's a helpful video, although it repeats the point you made (that if you double the distance between subject and light source you lose two stops of light) which isn't actually correct in most situations, most of the time, with most sources of light - although it's basically sound.

This tutorial may explain it better, because not only does it show the effect of moving the light source on the background, it also shows the effect it has on the subject too.
 
I know everyone has said this but... It's not a power issue, it's a control issue, you have to work with the Inverse Square Law, if the subject and background are similar distances from the light, they'll receive a similar amount of light. If the subject is far away from the background and the light is close to the subject, the background will get relatively much less light.

People shut down when we start talking about the maths of the ISL but it's really simple and once you have it 'in your head' many other problems are easily solved.
 
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