Image #1 

                       sample #1 

                       sample #2 

  “Capturing Alaska”
    with Wayde Carroll






Neutral Density Filter


 
    
   This past weekend I took my two children, seven- year old Jack, and three- year old Claire, up to Hatcher Pass to play in the snow. It was a glorious day with clear blue skies and warmth from the sun that made the frigid temperature bearable. A real plus when dealing with small children!
   I loved spending time with my kids. (I’ve never heard my daughter giggle so much as when I was pulling her through the snow on a tiny sled!) But a part of me couldn’t help wishing I could grab my camera from the car and head out for a day of shooting. I kept looking around and sighing “man, what a gorgeous day!”
   Luckily I got to at least scratch the itch a little.
   Once the sun started to drop and shadows filled the valley the temperature dropped dramatically. It was time to head in to Palmer for hot chocolate!
   As we were heading out we crossed over the Little Susitna River and I was able to grab a quick glimpse and I saw a scene I just had to try and capture. The protruding boulders in the river were capped with snow and one of the mountains in the background was bathed in the warm glow of the fading sun (see image #1). So I turned the car around, parked along the side of the road, grabbed my camera bag and tripod, and jumped out to find a decent composition.
 I also knew this would be a good example for this blog on when and how to use a neutral density filter.
   A what?
   I know, most of you haven’t heard of one much less carry one around but if you’re an aspiring photographer you should. Let me explain (as if you had a choice!).
   The beautiful scene before me held one serious photographic complication. The contrast range within the image was too great to be captured in one exposure. You see, the brightness of the sunlit mountain over powered the river, which was in full shadow. If I took a proper exposure for the mountain, the river would be seriously underexposed and rendered nearly black (see sample #1). If I exposed for the river, the mountain would be completely overexposed and become a white blob with no detail (see sample #2 ). This is where the neutral density filter comes in to play.
   A neutral density filter is a filter that has a neutral gray area that can be positioned over the brighter portion of your scene to bring its’ exposure reading closer to that of your darker area. You can get these filters with a gradual transition from light to dark or with a hard edged transition and you can get them in varying degrees of filtration from one stop on up to eight stops. Many photographers carry several variations for different circumstances but if you just want to buy one to start experimenting I would get a three-stop filter with the gradual transition from clear to neutral grey. The “neutral” color assures you accurate color rendition as opposed to a colored filter. That’s a good general filter I use a lot. Also, I would invest in one of the rectangular glass or hard plexi-glass systems that allow you greater control of positioning your filter.  I use the Singh- Ray Galen Rowell series. The circular screw on filters are gradated towards the middle and allow only one placement in your scene- in the middle.
   So, back to our scene. I found the composition (s) I liked and set up my camera on the tripod. Next I mounted the filter onto my lens. The best way to make sure your filter is positioned where you want it is to set a small aperture, f16 –f32, depress your depth of field preview button, and as you’re peering through your viewfinder, slowly slide your neutral density filter down until the gradation is where you need it. Now your ready to shoot!
   If you don’t have a depth of field preview you can make test exposures and check them on your screen and make adjustments as necessary.
   You can also solve this exposure problem by taking several different exposures- on a tripod- and combining them later in your photo editing software. I would much rather do a little extra work up front that will save me time later. Especially when you’re trying several different compositions. Good luck!