Great Blue Heron in Flight

When I woke up this morning the sun was brightly shining and I decided to go out and practice what I had learned at the workshop this past weekend. However, when I arrived at Oliver Mill Park, the sky was completely overcast and I probably could have shot in my usual mode which is Aperture Priority. If I shot in Aperture Priority I would not have educated myself. I set the camera to manual mode, ISO 800 and then picked the subject that would fill the frame of my 500 mm lens with a 1.7 converter. I took a test shot and adjusted the settings so that the histogram would be in the middle.

Midtone

After I did that I took pictures of the great black backed gulls and the great blue heron and then adjusted the settings in the camera to give the same exposure and obtain what I visualized to obtain tin the photo. In all the pictures the subject was expose correctly. I will continue to practice so that I get the technique down correctly. In order for this to work you do need to understand exposure triangle and the relationships between Aperture, Shutter Speed, and ISO. Changing any one of these three by a full stop will either double the amount the light or half the amount the light coming into the sensor. To keep the exposure the same say you open up the Aperture one full stop you must close the shutter speed one full stop.

Exposure triangle

Histogram demonstrating correct exposure on the gulls

If you learn the sunny f/16 rule it will give you a basis to learn how the exposure triangle is interrelated. Sunny 16 means on a clear bright sunny day from mid morning to mid afternoon the sun intensity is approximately the same. The rule is 1/ISO at f/16 which means at ISO 200 at f/16 the shutter speed will be 1/200. If you opened the Aperture to f/8 which is two stops open you then need to close the shutter speed to stops to 1/800.

In the scenarios shown in the chart below, the rule continues to apply. At each of the aperture settings the shutter speed should match the reciprocal of the ISO

Aperture	Lighting Scenario
f/22	Layer of Snow or at The Beach, Sunny Day
f/16	Sunny Day at Noon
f/11	Slightly Overcast
f/8	Overcast
f/5.6	Storm Clouds
f/4	Open Shade / Sunset

Since I capture my in images in the RAW format, i.e. utilize Lightroom and/or Photoshop along with plug-ins including Topaz and Nik to do my digital editing.