Long Exposures

This past May, Alissa and I bought a new home and needless to say we have many bare walls!  As I was placing Preston’s print order I thought to also order a 20×30 print for our home.  I chose an image that I took while on our family vacation this past July.  This particular photo was taken at the base of Medicine Bow peak, overlooking Lake Marie.  Medicine Bow has a 12,013ft summit and part of the Snowy Mountain Range, Wyoming.  This is practically straight out of the camera.  It was taken at night, on a tripod with a 407 second shutter speed.  Well….there’s nothing really “speedy” about it.  As always, I’ve included the shot info at the end of the post.

I may have left you wondering how this is possible.  This particular night there wasn’t even the ambient light of the moon.  The fact of the matter is that there is always light, however our eyes are not sensitive enough to see it.  The camera on the other hand, can see this light given you leave the shutter open for a long enough period of time.

In order for me to get the proper exposure for this shot I had to do some simple math.  I first set my camera to ISO 6400, which makes the camera extremely sensitive to light.  Next I set my f/stop to 2.8, which allows the maximum amount of light to enter through the lens.  I then took a test shot, at 1/80.  The shot was properly exposed but because I had the camera set to ISO6400 there was alot of digital noise / grain.  Here’s where the math comes in.

The first adjustment I made was with my ISO setting.  The shot you see above was shot at ISO200.  By setting the ISO to ISO3200 I’ve effectively halved the cameras sensitivity to light.  By setting the camera to ISO200, I’ll need 32 times more light in order to properly expose the photo.  Once my camera is set to ISO200, I now know that my shutter speed will need to be changed from 1/80 second to about 26 seconds. (0.8 x 32=25.6)

The second adjustment that needs to be made is the f/stop.  I chose f/11 for this shot to ensure proper focus throughout.  I’m sure f/8 or 9 would have worked equally as well.  By changing the f stop from 2.8 to 4, I’ve halved the amount of light that is allowed to pass through the lens.  By setting the camera to f/11, I will need 16 times more light.  The only way to compensate for this is to increase the shutter speed.  If at ISO200, f/2.8 I needed a 26 second shutter speed, I know that at ISO200, f/11 I will need a 416 second shutter speed.  (26 x 16 = 416)  The final shot settings were ISO200, f/11 @ 407 seconds.

Long exposures are wonderful.  The effects they have on water is fantastic, creating silky smooth surfaces.

I really enjoy landscape photography.  I get my inspiration from my friend Eduardo who I met while in California earlier this year.  He’s an amazing photographer.  Anyway, here are a few more from Wyoming.  Enjoy!

1.  ISO200 | 14mm f/11 @ 407 sec

2. ISO200 | 14mm f/2.8 @ 294 sec

3.  ISO200 | 15mm f/8 @  HDR

4.  ISO200 | 31mm f/2.8 @ 1/5000

5. ISO200 | 14mm f/8 @  HDR