Sunday, January 12, 2014

Photographing Falling Snow








And Getting Rid of the Blotches

It is a wonderful, but also occasionally painful fact that landscape photography is often at its best when the weather is at its worse.  This is certainly true when it comes to shooting the winter storms.  Whether gently settling or blown by ferocious winter gales, falling snow drops a lovely veil on any winter scene, but capturing the storm imposes a whole new set of opportunities and challenges.  These include both the practical difficulties of managing the cold and wet, and  also dealing with the fact that snow can appear completely differently depending on setting that are chosen in camera.

Practical Problems
 
The physical problems include keeping the camera, warm and dry and avoiding or removing the snow flakes that are inevitably attracted to the lens.  Simple preventive measures such as the use of a lens hood and avoiding aiming the camera directly into the flying snow can be very helpful, but in heavy snow I typically shroud my camera under a towel and only uncover the lens and viewfinder when I am ready to shoot.   Despite the best efforts, snow can attach to the lens.  It is important to check regularly and have dry lens cloths available to clear the view.  I have had the experience of taking a long series of images, only to discover that my lens had become blotched somewhere in the middle of the shoot. 

Basic Settings
Shooting falling snow requires a number of decisions about how you want the flakes to be portrayed.  Subtle differences in shutter, aperture and focal length can make a striking difference in the appearance and mood of the image. 

Shutter
Simply stated, long exposures, usually less that 1/100, will show

Central Square Storm 2 Seconds
the snow as streaks, while a quick shutter will catch the snow as individual flakes.  As longer exposures are used there is a point where the individual flakes disappear and what is left is a soft fog which intensifies with greater distance from the lens.  I saw this nicely displayed in my 2-3 second
exposures of the Christmas lights on Keene's Central Square.  The snow was coming down heavily but no falling flakes could be seen.  Of course the correct shutter will depend on how quickly the flakes are falling. often subtle differences in shutter can make a significant difference in the mood of the image.  Check out the tractor and barn comparison below.   Experimentation is always necessary. 


In the Storm, 1/90th

In the Storm, 1/250th



F13, 1/90th
Aperture
A small aperture, with a large depth of field, will include a greater depth of sharp flakes, which will tend to make the storm appear more intense.  A wide aperture will focus attention on a smaller, more intimate selection of flakes and the shallow depth of field can allow the snow to stand out better against the background's soft Bokeh. 


 



f20, 1/100th


1/250, 340mm
Focal Length
The foreshortening effects of telephoto lens' tend to compress deeper selections of snow again giving a more intense feel.  Wide angle lens' give a broader sense of the surrounding but may need heavier snow to capture the full power of the storm. 

 








Enhance Storm Intensity:Long Shutter, Small Aperture & Long Lens
1/6 th, f 16, 105mm


Crank the ISO
Of course in tough weather conditions compromises need to be
made. As always, the appropriate setting for each of these parameters is affected by the others.  In the dark of a storm there may not be enough light to combine a fast shutter with a small aperture.  Fortunately we now have the option to crank up the ISO.  Higher  ISO levels invariably result in more noise, but the good news is that there may be very few situations in which high ISO noise is less noticeable than in a blizzard.


Flash
Snow flake will stand out better, especially at night, if they are
Stone Bridge, Flash with Blotches
illuminated by a focused light source, such as a street light or car headlights, but here is probably no better way to stop falling snow dead in its track than to use flash.  Regardless of the  shutter speed the short duration of an electronic flash will freeze any nearby motion.  This effect will dissipate by the inverse square law as distance from the flash increases.  The problem with flash is that it most prominently lights the nearest flake, which are inevitably large and distracting.  With removal of the grotesque blotches (see below) the remaining flakes are more naturally highlighted  The combination of flash and natural light leads to a complex mixture of exposure and color temperature.  Again experimentation is in order.


Large Blotches Removed (See Below)



Ok, that is some of the basics.  Now let me finish with one of my pet peeves about falling snow images.  The Blotch.

 


Curing the Blotches
Blotched Storm
 

 For me "blotches" are the bane of my falling snow images.  You have undoubtedly seen beautiful atmospheric images of snow storms, but here and there are big blotches of white that seem out of place.  These white smudges come from the snow flakes that are close to the lens when the image is captured.  They are invariably out of focus and to me at least, extremely annoying.  Happily there are. number of ways to eliminate the blotch. 

Shade the Lens

 The simplest solution is to shade the lens from nearby flakes.  In the tractor by the barn comparison,  I shot from under a porch roof at Roads End Farm.  Magically, no blotches.  When a roof is not at hand an umbrella or a piece of card board can also help.  Just keep your shade out of the frame.






Central Square, 1/50th
Slow Shutter
The blotches are generally most noticeable at faster shutter speeds. With longer exposures the flakes are streaked and the smudged nearby flakes become less defined. Again the appropriate shutter will be dictated by the speed of snow fall and the size of the flakes.



 


Cloning and  Healing Brush
You knew we would have to get to Photoshop eventually.  Given the random complexity of the snow images, it is comparatively easy to use Cloning or the Healing Brush to replace the blotches.  In newer versions of Photoshop, the Content Aware Fill tool can also correct the scars. The automatic techniques, such as the Healing Brush usually do an amazing job, but occasionally I will use cloning to find a good source that matches the original background.


 

Multiple Image Layers 
My favorite approach to the blotch is to use multiple images.  Since the location of the blotches vary from image to image, I can use one image to patch another.  I pick the best of a series of images and then add the second best in a layer above the first.  After aligning the two images, I mask out the top layer.  I then scan the image and wherever a blotch appears I simply paint with white on the upper layer mask.  This nearly always brings up a section without the blotch. To me this is the most elegant solution, since the uncovered background tends to match that of the lower image. The blotches on the Stone Bridge above were cleaned with this technique.

The great thing about falling snow is that it provides a treasure chest of creative opportunities all within the easy reach to your camera's basic settings.  Now if we can get some snow out of this miserably cold weather, we will be set to go.  Get out there and experiment.

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