Allen Ellison’s Technobabble


Photographing Smoke
October 24, 2009, 3:29 am
Filed under: Photography | Tags: , , , , , , , ,

photograph of smoke using a Nikon D90 and 50mm lens

photograph of smoke using a Nikon D90 and 50mm lens

Over the last year I’ve taken my fair share of smoke pictures.  When I started out taking pictures of smoke, I was able to find a couple of short articles about photographing smoke, but they all seemed to stop at the basics.

They all said pretty much the same thing: maximize the signal-to-noise ratio (contrast).  But what does this mean?

Increasing the Signal making the smoke brighter, sharper and simpler

  • You can light the smoke using either an always-on light source (like a bright halogen lamp, a 500W lamp, or the sun) or a Flash. A Flash is generally preferable as it’s gentler on the environment than a 500W light bulb and the burst of light that most flashes put out is considerably stronger than any always-on light source you can buy.  That being said, I love using the sun as a light source — the photographs from doing so are distinct.
  • In general, the brighter the flash of light – the better. This is because you want the shutter speed to be as fast as possible and (probably more important), you want the f-stop setting to be as high as possible.  The higher the f-stop, the smaller the aperature the light comes through.  The smaller the aperature, the more likely that all of the smoke will appear to be focused. Now, there is a caveat that will be elaborated in the ‘reducing the noise’ section where increasing the flash’s brightness has a cost associated with it.
  • The Flash speed limit is usually 1/200. If you’re using a flash, your shutter speed will probably max out at 1/200 second and most cameras won’t let you even attempt a faster shutter speed if the flash is turned on, and the flash sync speed for most cameras maxes out at 1/200.  Even if you were to strong-arm your camera into doing faster, you’ll end up with a picture with only part of the image exposed to the flash — weird stuff. On the other hand, assuming that you’re in a reasonably dark room, you have an effective shutter speed that’s around 1/10000 of a second. Keep in mind however, the brighter the flash, the longer its duration — resulting in a slower effective shutter speed.

  • Put the light source(s) behind the smoke — shining the light through the smoke is much more effective than attempting to bounce the light off the smoke. In my experimentation, it was beneficial to use more than one light source.  I frequently would use a flash with a strong 300-500w incandescent and was excited with the results. It wasn’t intuitive to me that mixing the two would work.  After all, one light source had an effective shutter speed that was very fast, but the other is subject to the camera’s shutter speed which I might set as slow as 1/100 of a second. But rather than adding noticeable blur, it does serve to ‘smooth’ out the subject — adding to the illusion of solidity.
  • Go big or go small — I frequently would use a 12-24 mm wide angle lens.  While not the first lens that comes to mind when shooting small things, it worked well because it photographed objects well that were closer to the camera than a foot.  But it also worked well because it’s focus tolerance was extraordinarily forgiving — there were times I would set the focus manually before the first photograph — and not touch it for the remainder of the shoot. But unquestionably, the best photographs came from my 105mm macro lens, as I could get extraordinarily close.  However, since the depth of field can be so strong, it also means that it’s a full time job keeping the smoke in focus.  Adding an LED lamp close to the smoke helps with the focus.

Reducing the Noise — getting rid of visual clutter

  • Eliminate the possibility of background objects in the frame competing with the smoke you’re lighting.  Sometimes background objects can make the image more powerful but usually will make the image more confusing if they’re unintentional.
Image of Smoke but also featuring its origin container

Image of Smoke but also featuring its origin container

  • Use Flags — ‘flag’ is the technical term for a piece of cloth whose purpose is to block light.  While you can get flags from photography stores (slightly on the pricey side), black felt (even if faux) fabric or paper, or black foamboard stock will do in a pinch.
  • Use a Black Background — flags also make for a great background for the smoke, as it will tend to soak up any light that has spilled over.  I’m also a big fan of using chalkboards, because, even though they’re not as effective as the aforementioned, they have a texture that is somewhat pleasing in the background and usually is recognizable as a chalkboard.
  • Get rid of other ambient light — if you’re in a room with windows, wait until dark or block the windows.  Turn off un-necessary lights.  Be aware of mirrors or other reflective (glass) surfaces.  This advice might apply to you — or it might not — it depends on the intensity of your light source.  If you’re finding that you’re having to use an F-stop of 16 or higher, then chances are that the intensity of light you’re using as your source is so bright that the ambient light pales in comparison (assuming you’re using a shutter speed significantly less than 1 second).
  • Avoid Flare — whether it’s by using flags to block the flash’s light from entering the camera, using the hood that came with your lens, or by being selective about your shooting angle — avoid the light entering your camera directly.  Otherwise, flare will noticeably reduce the quality of the photograph.

[yet to come]

Secret Sauce — once you’ve mastered the basics, these hints will take you beyond

  • Use cones
    Using the Sun to light cone incense

    Using the Sun to light cone incense

    • consistent
    • low-maintenance
    • low fire hazard risk
    • non-alarming smell
    • focal point remains relatively stable
  • Corral your light
    Using a magnifying sheet on myself

    Using a 'magnifying sheet' on myself

    • snoots
    • grids/honeycombs
    • lenses
    • learn about your Flash(es)
    • fresnel lens / magnifying sheets
  • Direct your smoke
    Devices to manipulate smoke

    Devices to manipulate smoke

    • grates

      Using a window screen to slice and dice

      Using a window screen to slice and dice

    • cylinders
    • plumes
    • Create a plane
    • Be aware of the currents
  • Go hot and cold

     

    Getting ready to stifle smoke

    Getting ready to stifle smoke

    • Heat and accelerate
    • Choke and slow it down
  • Post-processing
    • positive images
    • negative images (inversion)

       

      Smoke inverted using an Adobe Lightroom Inversion filter

      Smoke inverted using an Adobe Lightroom Inversion filter

    • strong vs. weak contrast images
  • Regarding Color
    • adding color in post-processing
    • using gels on flashes, reflecting from colored surfaces, colored backdrops

       

      Using flash gels to colorize smoke

      Using flash gels to colorize smoke

    • naturally emerging colors
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