billyboy
04-24-2007, 02:33 PM
Interest has been expressed in capturing lightning on sensor, so I thought I'd share my technique with anyone who might be interested...
The bad thing about lightning is it's dangerous, so I would never attempt to shoot it outdoors in the middle of a raging storm. Just about everyone has a window in their house that one time or another faces an oncoming storm that can be opened during a shoot. Like a first floor bedroom... the higher the better. But for anyone who finds themself outside in the thick of it, here`s a link to a nifty site that reviews basic preventive measures during a lightning storm. It`s worth checking out just in case!
http://www.srh.noaa.gov/fwd/media/media/severe/rubber.htm
The good thing about lightning is that it provides its own light, so no need to worry about that aspect... and in fact it often acts as a remote flash to illuminate surroundings in often surprising ways.
Although you could be lucky enough to catch a flash during the day, this method works best at night because it involves leaving your shutter locked open for varying periods of time. With your DSLR mounted on a tripod, select an aperture of between f5,6 and f8. I usually use a focal length of between 50 and 80 mm for full frame (about 30 - 50 mm for APS-C sensor) so that a good flash will more or less fill the frame. When conditions look right, aim the camera in the direction you anticipate a flash to occur (in a good storm progression there are enough pre-killer flashes to let you know where they're likely), make sure the room is dark like the outside... then place a black card in front of the lens and lock the shutter open. This technique allows you to quickly flick the card out of the way in an instant, and avoids camera shake as the vibrations from manipulating the camera have had a chance to settle down before you start exposing the frame. I can often judge the time interval between good flashes, so I'll remove the card a bit before hand--as the aperture is fairly small and the surroundings are dark, you can usually leave the exposure for a goods 5 or 6 seconds or even longer before overexposing the scene. If you get a good flash, close the shutter and advance the frame. If not, advance the frame anyway. If you've got enough space on your card, it doesn't matter if you have a handful of blanks.
By the way, a note about focusing. Unless I can lock my autofocus on a distant tree or somesuch, I find it works best to lock the focus on infinity. The relatively short focal length and smallish aperture tend to ensure things are in focus if it`s only the flash you want to capture. Obviously if there`s a building or seomething else in the foreground, focusing on that takes priority.
Even if you manage to bag a killer flash, it may lack realism in that such a burst of light tends to blanch out any subleties of color... you see a lightning flash with the naked eye as a white streak, but boardered by a hue of blue to magenta, and it's just that dynamic that makes a lightning flash so visually startling. That's why I have a post production method of enhancement. I first select the entire flash (it may have several branches) using a magic wand type tool and finish it off minutely by hand, feather by a few pixels and copy this to a layer. I then recall the selection on the background layer and expand this by several pixels (start with 6 and experiment). Feather the selection by roughly the same amount and save to another layer. Fill this layer with a medium magenta, and place the first, non-expanded layer on top of the expanded magenta layer. Make sure the top layer is absolute white, and adjust saturation and brightness of the magenta layer to taste until the two layers gel with each other and the flash looks the way you see it in real life. Smaller branches can be darker magenta or even blue... you want to smell the ozone when you're through.
You can see from my sample of the Storm House that I've also added this dynamic to the cloud surrounding the flash. I selected an area that seemed right, gave tons of feathering, and just played with hue, saturation, brightness, levels... whatever works in your shot. As I had to import the whole sky for this collage to make it look real, I had to go through the pain of cutting out the sky where the branches from the trees in the house photo could show through. This took lots of patience, but the shot would not have worked otherwise. The driveway up to the house came from yet another photo and I colored the pavement to look as though reflecting the flash.
The second example, Midnight Cocktail, uses the same flash, but without the sky. I used Photoshop's lighting effects to make the flashpoint where the lightning appears to strike... and smash the glass... but that's another technique altogether!!
Jeeze that was long winded... I hope somebody is fanatic enough not to get bored half-way through. I myself am totally nuts over lightning (there's one or two other shots in my gallery that use it), and I hope this inspires one or two souls out there...
Thanks for looking, Bill
http://www.photozo.com/album/data/7739/Storm_House.jpg
Storm House
http://www.photozo.com/album/data/7739/Midnight_Cocktail.jpg
Midnight Cocktail
The bad thing about lightning is it's dangerous, so I would never attempt to shoot it outdoors in the middle of a raging storm. Just about everyone has a window in their house that one time or another faces an oncoming storm that can be opened during a shoot. Like a first floor bedroom... the higher the better. But for anyone who finds themself outside in the thick of it, here`s a link to a nifty site that reviews basic preventive measures during a lightning storm. It`s worth checking out just in case!
http://www.srh.noaa.gov/fwd/media/media/severe/rubber.htm
The good thing about lightning is that it provides its own light, so no need to worry about that aspect... and in fact it often acts as a remote flash to illuminate surroundings in often surprising ways.
Although you could be lucky enough to catch a flash during the day, this method works best at night because it involves leaving your shutter locked open for varying periods of time. With your DSLR mounted on a tripod, select an aperture of between f5,6 and f8. I usually use a focal length of between 50 and 80 mm for full frame (about 30 - 50 mm for APS-C sensor) so that a good flash will more or less fill the frame. When conditions look right, aim the camera in the direction you anticipate a flash to occur (in a good storm progression there are enough pre-killer flashes to let you know where they're likely), make sure the room is dark like the outside... then place a black card in front of the lens and lock the shutter open. This technique allows you to quickly flick the card out of the way in an instant, and avoids camera shake as the vibrations from manipulating the camera have had a chance to settle down before you start exposing the frame. I can often judge the time interval between good flashes, so I'll remove the card a bit before hand--as the aperture is fairly small and the surroundings are dark, you can usually leave the exposure for a goods 5 or 6 seconds or even longer before overexposing the scene. If you get a good flash, close the shutter and advance the frame. If not, advance the frame anyway. If you've got enough space on your card, it doesn't matter if you have a handful of blanks.
By the way, a note about focusing. Unless I can lock my autofocus on a distant tree or somesuch, I find it works best to lock the focus on infinity. The relatively short focal length and smallish aperture tend to ensure things are in focus if it`s only the flash you want to capture. Obviously if there`s a building or seomething else in the foreground, focusing on that takes priority.
Even if you manage to bag a killer flash, it may lack realism in that such a burst of light tends to blanch out any subleties of color... you see a lightning flash with the naked eye as a white streak, but boardered by a hue of blue to magenta, and it's just that dynamic that makes a lightning flash so visually startling. That's why I have a post production method of enhancement. I first select the entire flash (it may have several branches) using a magic wand type tool and finish it off minutely by hand, feather by a few pixels and copy this to a layer. I then recall the selection on the background layer and expand this by several pixels (start with 6 and experiment). Feather the selection by roughly the same amount and save to another layer. Fill this layer with a medium magenta, and place the first, non-expanded layer on top of the expanded magenta layer. Make sure the top layer is absolute white, and adjust saturation and brightness of the magenta layer to taste until the two layers gel with each other and the flash looks the way you see it in real life. Smaller branches can be darker magenta or even blue... you want to smell the ozone when you're through.
You can see from my sample of the Storm House that I've also added this dynamic to the cloud surrounding the flash. I selected an area that seemed right, gave tons of feathering, and just played with hue, saturation, brightness, levels... whatever works in your shot. As I had to import the whole sky for this collage to make it look real, I had to go through the pain of cutting out the sky where the branches from the trees in the house photo could show through. This took lots of patience, but the shot would not have worked otherwise. The driveway up to the house came from yet another photo and I colored the pavement to look as though reflecting the flash.
The second example, Midnight Cocktail, uses the same flash, but without the sky. I used Photoshop's lighting effects to make the flashpoint where the lightning appears to strike... and smash the glass... but that's another technique altogether!!
Jeeze that was long winded... I hope somebody is fanatic enough not to get bored half-way through. I myself am totally nuts over lightning (there's one or two other shots in my gallery that use it), and I hope this inspires one or two souls out there...
Thanks for looking, Bill
http://www.photozo.com/album/data/7739/Storm_House.jpg
Storm House
http://www.photozo.com/album/data/7739/Midnight_Cocktail.jpg
Midnight Cocktail