Principles of Exposure: Understanding Light Sensitivity and Noise through ISO Control

Assignment: Create an ISO Test Strip

Students, your new assignment is a challenge for you to demonstrate an understanding of ISO and how to adjust both Aperture and Shutter Speed to maintain proper Exposure Values (EV) across multiple ISO settings. In this assignment you will find/create a still life subject and shoot 4 images that have similar exposures but increases in ISO. Little to no change should be seen in light/dark values, only additional grain/noise should be noticed as increasing. Overlay your images as shown below using Photoshop layers and document your exposure settings.

This image was created in our studio/classroom with our class cameras. Strive to create an ISO test image of equal quality. Image should be properly exposed to begin with, show a range of ISO from low to high and be composited in Photoshop to resemble the sample above.

Assignment Deliverables:

This excellent student example was taken outside, use a tripod for best image alignment. Work quickly when outside, clouds or changes in light can affect your final results.

Part A -  ISO Test Image:

1. Produce a series of images (4) that demonstrate the impact that ISO has on the noise in an image while maintaining consistent exposure. Choose a creative still life subject and produce 4 images showing the range of ISO settings from low to high. Mimic the ISO Comparison images above. You will need to adjust either shutter speed or aperture to keep even exposure, don't let the different examples get darker or lighter.
2. Compile the images in slices to show the even exposure levels, as illustrated above. Use the selection tools to reveal each slice and add text details and focus on quality of presentation for your test image

Part B - Written Synopsis of Exposure Principles: 

1. Written Synopsis of the Exposure Principles. Write a short 3 paragraph description of the three principles of exposure, shutter speed, aperture and iso, what they mean and how you utilize them in photography, how to they alter your images, etc... 
2. Post your essay to your blog with 1 image you have taken that demonstrates each exposure principal (use your ISO test image you created for ISO demonstration)...

Difficulties?
Try this exposure calculator to find your equivalent exposure across a range of ISO's

Have fun and ask questions if you get stuck! - Mr.W