Science Buddies: "Ask an Expert"

dear sir/madam
I've just confirm my science project topic as 'digital Photos and Dynamic Range.' I found this topic under the physical science section. my question is: what should my research paper be about? can i just do a paper on Photography or cameras or what? thanks a lot for the help in advance.
reagards

Hi emirates,

What you proposed is a good first step. I suggest you take a careful read of the project description at:
https://www.sciencebuddies.org/science- ... ?from=Home
You'll notice that the project uses a manual mode on the camera, and explores exposures at different manual settings of exposure time, with a constant manual setting of focal distance (lens aperture).

So, a paper needs to include data on shutter speed and lens aperture. The project page has references for both these topics under "The Shutter Speed" and "The Lens Aperture."

' I found this topic under the physical science section. my question is: what should my research paper be about?

Sorry, that is something that you have to decide for yourself. As long as you aren't constrained by some class or teacher or advisor's requirements, you have a clean slate to work with. This site is aimed at helping people with science fair projects and they require coming up with a hypothesis and then coming up with an experiment to attempt to prove or disprove that hypothesis. In other words, using the scientific method to investigate something of interest. Research papers aren't what this site is aimed at.

thanks for the reply. I'll build on that and go on. I'm planning to use a Powershot S5 IS for this project. It's a pro-sumer.

Hi emirates,

You're welcome.

The Powershot S5 IS seems to be a very capable camera, and you're lucky to have access to one. Just looking at its capabilities, the camera seems to be able to do what you need for the experiment:

manual setting: http://web.canon.jp/imaging/mode/camera ... tml#manual
storage of custom settings: http://web.canon.jp/imaging/mode/camera/custom-e.html

am i right to state that my purpose for the project is to find the best lens aperture and shuttle speed to take the pictures? I'm also planning to widen my project to finding the best lens aperture and shuttle speed for the following: landscape, portrait, action, night, and macro. Is there any other way I can pushed the Project into more depth?

davidkallman wrote:Hi emirates,

You're welcome.

The Powershot S5 IS seems to be a very capable camera, and you're lucky to have access to one. Just looking at its capabilities, the camera seems to be able to do what you need for the experiment:

manual setting: http://web.canon.jp/imaging/mode/camera ... tml#manual
storage of custom settings: http://web.canon.jp/imaging/mode/camera/custom-e.html

thanks for the links they were really helpful.

am i right to state that my purpose for the project is to find the best lens aperture and shuttle speed to take the pictures? I'm also planning to widen my project to finding the best lens aperture and shuttle speed for the following: landscape, portrait, action, night, and macro. Is there any other way I can pushed the Project into more depth?

You might want to visit http://photo.net/ and read some of the "Learn About Photography" particularly http://photo.net/learn/making-photographs/

IMO: There is NO best aperature or shutter speed or focal length or format to capture images. From an artistic point of view, what is in focus, what is blurred (motion or depth of field of focus) where it placed in the image, where it is placed tonally in the captured image, where the light is coming from and what kind of lighting, how the foreground and background are treated all lead to a strong or weak image for a given purpose. Two highly skilled photographers photographing the same thing at the same time can create very different images and both can appreciate the others very different work.

Hi Emirates,
I agree with Craig's point that you'll want to clearly define what you mean by "best aperture and shutter speed" to take a photo.
Good luck!
Chris

From a scientific viewpoint, "exposure" (how light from a given image is rendered tonally on film or a digital sensor) is affected by aperture, shutter speed, and film/sensor sensitivity (usually expressed in ISO). For a given film/sensor ISO choice, multiple pairings of aperture and shutter speed will provide the exact same exposure. For example, 1/f16 at 1/30 is equivalent to 1/f11 at 1/60, 1/f8 at 1/125, 1/f5.6 at 1/250, 1/f4 at 1/500, 1/f2.8 at 1/1000, and 1/f2 at 1/2000. This is just a case of doubling the area of the aperture "iris" thus doubling the amount of light per second that can pass through and halving the time it is allowed to pass yielding the same amount of light falling on the film/sensor.

If the illumination and focus is constant and the camera and everything in the image are stationary (not moving with respect to each other), then the only difference in these captured images taken with equivalent exposure will be depth of field effects.

You should do some reading on Depth of Field. A simple experiment is to try some close up photography of a ruler or yard/meter stick that is placed diagonally from foreground to background as it goes across the field of view. Place the ruled device as close to the camera as your lens will allow you to focus on the middle of it and use the biggest aperature available (1/f2 in the above example for an "f2" lens). On the captured image, you should see that the middle is in focus and things closer and farther away are out of focus. Without changing anything else, take a series of images decreasing the aperture opening by 1 f-stop (and doubling the exposure time) and compare the images to determine what appears in focus. If you were using film, you could enlarge (magnify) the image and find out that at higher magnifications, all the portions of the ruler that appeared in focus at a smaller image size really weren't in focus. Unfortunately, enlarging digital images creates digital artifacts that don't allow you to do this.

Once you understand the circle of confusion aspects of Depth of Field and magnification, you can apply this same understanding to relative motion. If an edge or point on an object moves during the exposure by less than the circle of confusion in the captured image at the enlarging factor, it will appear in focus; however, if it moves more than this amount, it will appear blurred.

thanks for the advice and the links. really appreciate your helps. In fact this WAS the reason i chose this project- to deepen my photography knowledge. I'll study all the info and web links carefully and hope to settle on a firm experiment soon (running out of time)

The project described at https://www.sciencebuddies.org/science- ... ?from=Home was designed to measure the dynamic exposure range of the digital sensor in a camera which makes it a scientific and/or engineering investigation and removes it entirely from the more subjective and artistic aspects of digital photography.

If you want to (or are required to) do a scientific investigation, be sure that you read up on the scientific method and formulate your hypothesis and experiments to avoid the subjective and artistic aspects of photography.

Given a short amount of time to decide on and finish a project, investigating exposure is certainly simpler than investigating depth of field of focus which is simpler than investigating motion blur. All of these are simpler than investigating issues with low light timed exposures, color correction, shadow detail/noise reduction, and digital artifacts.

Hi!
I still can't figure out what my variables should be, my constant....subsequently my hypothesis. If I were to water down into easy steps what would it be?
I've also been thinking whether there is another idea for an experiment that would fall into photography an fit my level at Grade 10. Ideals PLEASE!
thanks in advance.

Hi emirates,

The concepts are all explained at the Science Fair Project Guide:
https://www.sciencebuddies.org/science- ... ?From=body
There are two pages explaining variables. After reading this material, please buzz back in if you have a specific question. Thanks.

A whole set of photography projects is at Photography, Digital Photography & Video Project Ideas:
https://www.sciencebuddies.org/science- ... hoto.shtml

I wouldn't get too fixated on grade level, though it would be better to pick one of the more advanced projects on the Ideas page above. What is most important, though, is to pick a project that interests you!

This just a 1st draft plan:
I'll probably take 50 landscape shots on a tripod and than read and grade from best no.1 to worse no.50 by the support of a histogram. That just a start plan that pop. my hypothesis will than be based on what i think is the best and worse through sight. I'll change variable to 50 shots taken with a lens hood. that's as far as I can plan up now.....any suggestions?

I'm halfway through my experiment. Followed the draft plan from science buddies on digital photos and dynamic range. But i'm getting quite confused now. I'm done with taking pictures, (I took shots with 14 different shutter speeds with constant factors of ISO and aperture 4 times) done with analyzing the pictures ( all of them). my questions are:
1) i understand i'll make a graph to show results with the shutter speeds as the x axis. do i take the min.+ mean.+ mode.+ max. + Std. Dev. and get an average of all? Isn't that why we are told to collect all this data and take note of them on a table?

2) what dose the short-form Std. Dev. stand for?

this is my table so far:
Shutter Speed Pixel Gray Level Statistics
Mean Std. Dev. Min Max Mode File Name
8 253.00 0.038 216 255 253 IMG_3088
4 253.000 0.035 216 255 253 IMG_3096
2 253.000 0.031 216 255 253 IMG_3100
1 253.000 0.026 219 255 253 IMG_3013
1/2 253.000 0.013 232 255 253 IMG_3108
1/4 244.214 198.83 187 251 245 IMG_3110
1/8 196.310 3.166 148 221 198 IMG_3113
1/15 147.417 3.692 103 208 148 IMG_3118
1/30 114.035 4.581 56 195 115 IMG_3122
1/60 74.678 5.752 21 163 75 IMG_3127
1/125 26.949 4.377 1 150 27 IMG_3133
1/500 18.520 4.029 0 141 18 IMG_3135
1/500 6.657 3.002 0 136 6 IMG_3140
1/1000 3.046 2.257 0 138 2 IMG_3144

Lets forget about more complicated math for a moment and just think about MIN and MAX and what they mean in a digital JPEG image with 8 bit resolution. A MIN of 0 in an image means there was at least one pixel that did not register any light so we don't know how dark it(they) really was(were), there is just something darker than what the camera can measure at that setting. A MAX of 255 in an 8 bit JPEG image means there was at least one pixel that was brighter than what the camera could measure at that setting. All 8 bit JPEG images with either a 0 or a 255 in a pixel means that the image exceeded the dynamic range of the camera at the setting it was taken. The only thing that we can learn from these images wrt dynamic range is that it was greater than what the camera could render at the setting involved. The more interesting results are the images where all pixels are within the dynamic range of the camera.

Given that you are only presenting what appears to be one set of numbers instead of separate Red/Green/Blue numbers, I'm assuming you took the pictures in black and white mode. If not, then you need to be dealing with each color channel separately wrt dynamic range.

Now for some more complicated math (but restricted to cases where the image was within the dynamic range). When the MEAN (midpoint between MIN and MAX values) and the AVERAGE (sum of all pixel values divided by number of values or pixels for a given color channel or black and white composite) differ considerably, we know that the distribution of the pixel values in the histogram is not very uniform over the dynamic range (MIN to MAX). The STANDARD DEVIATION is a better measure of the uniformity of the pixel values. It adds up the square of the deviation of each pixel value from the AVERAGE and divides by the number of pixel values. The smaller this standardized deviation is, the more uniform the pixel values are spread from MIN to MAX. This can be seen in the histogram view of the camera.

Now for what you want to graph. You need to go back to your hypothesis. What is it that you are trying to prove or disprove? What mathmatical representation is most effective at demonstrating how well your hypothesis conforms to your test results? What mathmatical values or tests then confirm that the your demonstration variables are valid?

in contrast to other experiments i've done this one dosen't have a hypothesis....the experiment was to find out the dynamic range of my camera. OK now with all this data...seems like i've hit a rock....i don't know how to make that sample graph with my results and determine my camera's dynamic range?
https://www.sciencebuddies.org/science- ... ?from=Home
as in step 5 of the experiment.