Digital Photos and Shutter Speed
Background:
Pixel gray levels-A series of achromatic tones having varying proportions of white and black, to give a full range of grays between white and black.
Saturation-Vividness of hue; degree of difference from a gray of the same lightness or brightness. Also called intensity.
Dynamic range-in a digital image, the number of possible colors or shades of gray that can be included in a particular image
Aperture-Also called aperture stop. An opening, usually circular, that limits the quantity of light that can enter an optical instrument.
Shutter speed-In photography, shutter speed is the length of time a shutter is open; the total exposure is proportional to this exposure time, or duration of light reaching the film or image sensor.
Experimental Design-
Problem- How does the shutter speed affect the lighting of a photo?
Hypothesis- I hypothesize that the higher shutter speed I use, the darker the photo will be.
Rationale-
I will be able to learn how to use my camera more efficiently, and take better quality photos. The photos would not be grainy, they would show their true colors.
Materials used- SLR camera, ImageJ, and a sheet of white paper.
Procedure-
1.Take a sheet of white paper and hold it out to the sun.
2.Using your camera in black & white mode, take pictures of the paper, using different shutter speeds everytime, to the nearest whole number.
3.upload the photos onto ImageJ and retrieve the histogram.
4.Using the information of the histogram, create a data chart, recording the file name, shutter speed, mean, std. dev., min, max, and mode.
5.Plot the information on a graph, comparing the shutter speed to the mode.
6.From your graph, determine the dynamic range of your camera.
7. REVISE REDO AND REPEAT!(set 2)
Documentation-
Data- of the pixel gray level statistics. Here, I recorded the file name, shutter speed, and the pixel gray level statistics. With this, it is easy to compare all of the pictures, and see the change in light.
Set 1
Set 2
Statisticaly Analysis- Mode: y-axis; Shutter Speed: x-axis. The mode is the highest number of pixel color that appeared. The shutter speed is the rate at which the shutter stayed open. Comparing both graphs, you can see that the results of both sets was about the same, whith slight variation. The first few pictures came out very similar, bright. But, as the shutter speed becomes faster, you can see more change, it gets darker. Then towards the last few pictures, it is so dark that it is hard to make out any diffrences, even though there is.
Conclusion-
To summarize, my hypothesis was right. Shutter speed is the length of time a shutter is open, which affects the amount of light entering the lens. When I had the shutter open for a longer time, more light was able to be captured and the result was a brighter picture. When the shutter speed was set at a faster rate, less light was captured which resulted in darker pictures. So, I also came to conclusion that when it is night, or darker outside, it is best to use a lower shutter speed because more light collects, and the picture brightens up allowing you to see more than you normally would. Also, if it is lighter outside, or the day, you should use a higher shutter speed, this allows only small amounts of light into the lens, allowing you to see clearly. If you used a lower speed, the picture would cloud up in light, and it would be hard to make anything out. To add, if it is dim out or inside, you should set the shutter speed to a medium speed.
Reference-
http://www.sciencebuddies.com
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