December 22, 2011

off-camera flash photography tip – find your background, then your settings

With flash photography on location, we nearly always start off by figuring out what we want to do in relation to our available light. We might just need fill-flash, or or flash might need to do the “heavy lifting” and expose correctly for our subject in relation to the available light.

When we have our subject in (relative) shade, and need to figure out our flash exposure, we also need to decide exactly what our background is. It usually works best to be specific about our background … and how we position ourselves and our subject in relation to that.

So let’s run through that thought-process, using the image at the top.  Alex was our delightful model today during an individual workshop in Manhattan.


A point that I often underline here, is that we can’t expose correctly for all the areas in our background. We have to choose which part of our background is important, and base our exposure on that.

For example, here is a street scene in Manhattan. Exposing for the sky, the street goes completely dark.
1/250 @ f11 @ 200 ISO

This is to illustrate that I can’t expose correctly for the sky and the street scene. I have to decide.

Adding flash to this to expose correctly for Alex, still leaves us with an image that doesn’t make sense. She’s lost in a pool of black surroundings.

Positioning myself so that I can shoot up and use the sky as my background, makes much more sense.

At this point, I had changed my exposure to 1/250 @ f16 @ 200 ISO to really saturate the sky.  There is no specific correct exposure here for the sky. I can choose how I want to have the background / the sky appear.

Adding manual off-camera flash to this mix, immediately gives a dramatic look.

The vertical shot looks good, but half the frame is dark. It would need additional flashes, or something there to help delineate her legs against the background.

The composition just makes more sense as a horizontal photo, with Alex placed against the sky.

The final image again …

.. but with the image sweetened a bit using Topaz Adjust in an Adjustment Layer in Photoshop to give the photograph a bit more snap, as described in that article.

Here is the pull-back shot:

To get any kind of detail in the surrounding areas, and not have it appear black, I dragged my shutter to 1/15 of a second. Not a sensible shutter speed here when hand-holding the camera. It was just to illustrate where we were.

Since we were shooting with manual flash here, I couldn’t as easily change my aperture and ISO as I might have if TTL flash was an option with our setup. Therefore my shutter speed was the easiest to change and affect my ambient light only.  (It’s my independent control for available light when shooting with manual flash.)

FInally, here is the image as I preferred it to be cropped. It was sweetened a bit in Photoshop with using Topaz Adjust, but the sky was not dodged and burnt or manipulated. It appears that saturated and dramatic because that is how we exposed for it.

1/250 @ f16 @ 200 ISO … 24-70mm lens zoomed to 35mm (but image cropped square)

 

step-by-step, the metering technique used for the manual flash

  1. we decided on the aperture and ISO we want to use, based on what we wanted to do with our background.
  2. since we’re shooting in bright light, our lowest ISO is our best option.
  3. we’re shooting at maximum sync speed, since that is the most sensible shutter speed choice now.
  4. since manual flash was used, that means aperture and ISO has now been fixed for us.
  5. that leaves distance and power of our flash, as the other two controls.
  6. knowing we need to dump f16 @ 200 ISO worth of light from the Q-flash in a softbox with a single baffle, the flash was set to full manual output.  Everything the flash could give.
  7. that means our power was decided for us.  (Due to bright sky)
  8. then we  just had to use a lightmeter to measure our output (in f-stop readings). Holding the monopod and softbox up, I moved forward until the other photographer read f/16 on the lightmeter. Remember, the distance here is the distance from the light-source to the subject, not the photographer’s distance to the subject.
  9. now all our settings for flash are correct … in relation to our chosen background.

 

related articles

 

equipment used during this photo session

 

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{ 13 comments. } Add a Comment

1 Erwin Beckers December 23, 2011 at 5:43 am

Hi Neil,
great article again. You have a way of making OCF sound so easy ;-)
You mentioned your qflash. Would this also have been possible using a normal 580EXII speedlite or do you really need the extra power of a qflash for this?

Regards
Erwin

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2 Neil vN December 23, 2011 at 11:09 am

Erwin .. even with the Q-flash (and reflector dish), we had to remove one of the baffles from the softbox to get enough light on her for an f16 aperture. This would be out of the range of a speedlight, by around a stop or two.

If I had used a speedlight, I would’ve squeezed maybe f11 or so from it … which means the sky would’ve been a stop brighter. That’s not a huge difference in the final image though, and I doubt anyone looking at the photograph would’ve then said it needed a darker sky. So there is leeway here.

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3 Praveen December 24, 2011 at 12:38 pm

Hi Neil,

your website is inspirational. This weekend i got to try some of the techniques that you’ve explained in your posts and i couldn’t believe the results that i was seeing (nowhere close to your results though, as yet :-) ).
Just stopped by to thank you and looking forward to pick up many more ideas/techniques. so thanks again and merry Christmas to everyone in your team!

Praveen

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4 Tony Sale February 5, 2012 at 5:53 pm

Cool trick, cool tutorial I shall be out trying this very soon. Thanks Neil.

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5 Elaine March 5, 2012 at 8:08 am

Since we were shooting with manual flash here, I couldn’t as easily change my aperture and ISO as I might have if TTL flash was an option with our setup.

Hi Neil, please spell out why TTL flash was not an option here.
Many thanks

Reply

6 Neil vN March 5, 2012 at 11:48 am

We were shooting with the Quantum flash, using the PocketWizard Plus II units. So there was no TTL capability.

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7 Curt Gideon March 22, 2012 at 11:11 pm

Hi Neil, if your shooting in manuel mode on the Q flash why is it necessary to adjust the iso and f stop that your camera is set to… your in manual? there is no zoom with the Qt5dr and the power is what ever you have set it to right? so why not just adjust your power output only…
Thanks.

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8 Neil vN May 2, 2012 at 11:48 pm

A specific power setting on the Q-flash would dictate your ISO / Aperture / Distance combination.

With this scenario above, the sky was super-bright, and I was trying to match the exposure (via flash) of my subject, with the bright background.

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9 Eugene Struthers June 11, 2014 at 3:52 pm

Hi,

Wouldn’t it make sense to lower your shutter speed to allow in more ambient light say 1/160 as your aperture is controlling the flash out put. As the models black dress blends in with the black back ground. Introducing a bit of ambient light would have pulled & push her out against the back ground. Say f/11 @ ISO 200. I submitted a similar image for my final Fashion photography exam and got marked down. As my models out could not be distinguished from the back ground. And the clothing just faded into the back ground. It seemed to blend in with the dark back ground. I would be interested to know what you Quantum flash settings were.

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10 Neil vN June 11, 2014 at 4:02 pm

Allowing more light in, would’ve brightened the clouds, losing some of the drama there.

The lack of detail in the black dress does concern me, and certainly did so at the time. But with the square crop, the black dress and pathway becomes a monolithic black shape in the frame, dominating everything, except for the warm tones of her skin and the hat.

So for some, that composition and treatment would work – for others it would pull the image right down because it doesn’t conform to what we’re told is correct. Ultimately, it’s a matter of preference and taste.

So I do see the problems with this image in using only one light source – several would’ve been better and allowed more nuanced lighting. However, I do think this image can stand on its own, as this is how I did it, and like it.

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11 Neil vN June 11, 2014 at 4:02 pm

The specific settings for the Quantum flash is given in step 6.

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12 Chikara June 11, 2014 at 5:51 pm

Hello Neil,

Very nice article. Please keep them coming. Learning from the best.

Please correct me if I am wrong

1) You couldnt go above sync speed 1/250 because it will weaken the speedlight which is already in a softbox 1.1) Wouldnt an umbrella give you more spread thus lighting up her lower half (ok you didnt have one with you)?
2) Taking into account (1), you had no choice but to close down to limit the light because you were exposing for details in the sky
3) Could the image be stronger if you had separation? 3.1) Use a reflector propped up by the assistance leg to light up her lower half? 3.2) or use a second flash to the side (perhaps use ratios 1:3)?

Thanks for your thoughts Neil

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13 Neil vN June 11, 2014 at 6:26 pm

1. The Quantum doesn’t allow high-speed flash sync. So maximum flash sync speed is the max we can go with, or else we get that black band across the image.

1.1. An umbrella usually disperses the light even more.

2. We were at maximum output on our flash, because of the decision to expose for the sky, and that forced a small aperture choice on us.

3. Yes, the image might have been better with more nuanced light on her, and more detail in the black. Certainly, a light from the back would’ve helped separate her from the background.

So either take this as a tutorial on how to get the the best camera & flash settings, or take it as a tutorial in what you can achieve with just one light. Then improvise from there.

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