Tuesday, February 7, 2012

E is for EXPOSURE


Week two of the 6-week on-line Digital Photography Basics course I'm taking focused on EXPOSURE.

I learned that there is an "exposure triangle" where the combination of the size of the lens opening (Aperture), the length of time that the camera sensor is opened (Shutter speed) and the  sensitivity of the sensor (ISO Setting) work together to capture the  scene. When one part of the equation is off, it affects the outcome of the photo.  
Who knew math and geometry was part of photography? 

When a photo is too light, it is over-exposed. The white area is referred to as being "blown out "and the camera fills it in with white pixels. It cannot be rescued- even with editing programs.                                   When a photo turns out too dark, it is considered underexposed. The sensor responds by filling in the area with black pixels.   

Since it's often difficult to discern a good photo by viewing it on the camera screen, there is a graph in the camera that aids the photographer in exposure alignment. The graph is known as a Histogram and  measures placement of light and dark. If a photo is over-exposed the peaks will be skewed to the right and if under-exposed; skewed to the left.
To compensate for exposure problems, the camera has a setting known as Exposure compensation! By moving the adjuster to the left or right, the camera can adapt to the  available light.

For more practice in this lesson, I photographed a plant near a window on the right, at dusk, but with white Christmas lights to the lower left. It's somewhat dark.  I thing the lights would have been more effective if  placed behind the plant.

   This one is over-exposed- but I really like it! It feels like a water color painting. That's so cool! 

So much to learn!  The more I'm EXPOSED to the workings of photography, the more fun I'm having! I never dreamed that I would be considered as having "artistic" abilities.                                                         
   
                                                                                   
                                                          

5 comments:

  1. Great post! I so enjoy (and learn from) your posts.

    One thing I think is cool (but haven't tried yet) is HDR (high dynamic range) photography. You set the camera to take a set of three bracketed exposures one too dark, one in the middle and one too light. Then the HDR software combines the three so you get very dramatic, detailed photos with a wide range of highs and lows of light. (If you google it you'll see examples.) That's one of those "someday" things for me! It would do great with my sunset photos. Those are really challenging -especially before the sun is below the horizon - because the same photo has both over and underexposed sections.

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  2. I LOVE photography and once in a while, I'll even take a really good picture. I just don't have the patience to learn the skills very well. (Or maybe it's the time I don't have?) Thanks for the lesson!

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  3. Love your examples too. Great E word!

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  4. I LOVE your posts. So very interesting! (and Shelley's sounds cool too - though WAY beyond my understanding!)

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  5. I just saw a Photoshop tutorial for fixing overexposed pictures. Like you, though, sometimes I LIKE them that way!

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