Posts Tagged ‘crepuscular rays’

Good Morning Wisconsin!

May 7, 2013
Crepus

Crepusculur rays originating from clouds below the horizon.

The above image is an unusual example  of crepuscular rays. The name comes from their typical appearance during crepuscular hours (those around dawn and dusk), when the contrasts between light and dark are the most obvious. Crepuscular comes from the Latin word crepusculum meaning twilight.

A key component for crepuscular rays is the casting of a shadow. The shadow can be due to most anything, typically clouds. The result is sunlight broken into darkened areas (in the shadow) and lighted areas. The above image was attained prior to sunrise with the crepuscular rays caused by clouds below the horizon.

The visible beams always appear to spread out from the light source. In the above image the rays appear to diverge  from the base of the silo.  When I noticed the crepuscular rays forming, I changed my position allowing the rays to appear to be related to the farm buildings.

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Neighbors Magazine – Lime lake

August 2, 2012

This image of Lime Lake is this month’s cover of Neighbors Magazine.  http://issuu.com/rj200/docs/120809?mode=embed

If you have found your way to my blog via Neighbors, keep checking back as I will be posting additional images from the current issue with a bit more background information than is contained in the publication.  See Neighbors for information about a special promotion where you can order this image from Koertens Fine Framing and Gifts in Stevens Point, WI at a reduced price until October 1.

Beams of light radiating from the sun become visible when shadows are formed and light is scattered by particulates in the atmosphere. These crepuscular rays can be seen forming at three distinct cloud banks above Lime Lake in eastern Portage County, Wisconsin.  If conditions are just right, the rays can be seen traveling the entire sky to the opposite horizon.

Lime Lake is one of the lakes in Portage County draining initially to the east.  A remnant of our glacial past, it was formed by a huge block of ice left behind by the retreating glacier.  The ice chunk depressed the ground underneath and was subsequently surround by glacial till forming a depression that would become Lime Lake. The image was captured from the western ridge overlooking the lake. Drainage for the lake exits through the gap seen in the distance.

This image is an HDR and was constructed from five separate images. This technique allowed me to create an image that shows a greater dynamic range than is typically available in a single exposure. There is far greater detail in the shadows and highlights than the camera can capture in a single exposure but similar to what the human eye can perceive. The images were captured using a static aperture but variable shutter speed resulting in a full f-stop between images. My camera was on a tripod and I used a timer and mirror lock-up to prevent camera shake during image capture.  Images were combined using Photoshop  and a Photomatix tone mapping plug-in.

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