Aperture, ISO and Shutter Speed

As part of the lesson, today we explored different camera techniques to achieve different outcomes. For example, the shutter speed on a camera is used to control the amount of time in which the camera lens is exposed to light. However, modifying the speed of the shutter speed directly affects the motion blur of the final image; a faster shutter speed will result in a more stable film/image, whilst a slower shutter speed will result in more motion blur being present. Today I experimented with shutter speed, aperture and ISO.

The aperture is responsible for exactly how much light enters the camera lens. Altering the F-Stop will impact on the depth of field of the final image/film. A lower F-Stop will allow more light to enter the camera lens, which results in a more shallow depth of field; whereas, a higher F-Stop will allow less light to enter the camera lens, which results in a wider depth of field.

ISO measures the sensitivity of a film, to lighting. Altering the ISO will impact the lighting of the final image/film. Having the ISO set to a lower value (i.e. 100) ensures that the grain is kept to a minimal, thus resulting in a higher quality for the final product. Increasing the ISO to a larger number (i.e. 1500) enables the user to capture more lighting within their production, however, sacrifices the quality of the image to do so as higher grain will be evident.



A short video that displays my experimentation with different camera techniques can be found embedded below...

Taking part in this activity allowed me to develop my camera techniques; I am now confident that I am able to sacrifice one of these three features (ISO, Shutter speed or Aperture) and still be able to achieve adequate

Shutter Speed

The shutter speed is responsible for how much light manages to enter the camera lens. This is done by a shutter that slams shut within a pre-set time, disallowing anymore light to enter the lens. The more time that is pre-set by the user for the shutter to shut, will mean more light for the image; however because the image is exposed to light for a longer period of time, the photographer may find that objects/people in motion during the time the image was taken will experience motion blur. For my experimentation on shutter speed, I needed a subject that would be in motion over a short distance; knowing this I chose to take still images of cars driving by a street.

In my first example, I chose a slower shutter speed (1/30th of a second). The results I would expect to see would be the a car that would be difficult to decode the features of due to the motion blur. Below is the image of my first test.

Just as I has previously predicted, due to the elongated time span the shutter was allowed to remain open for; allowing light to enter the camera lens, the 'Ford KA' in motion in this image is motion blurred.

In my second example, I chose to increase the shutter speed to a relatively normal rate (1/50th of a second). The results I am expecting to see is virtually the same image of a car driving pass, in the street, motion blurred. Below is the image of my second test.

Although the car in this image appears to be slightly less motion blurred, there is more motion blur than I had expected. This anomaly may have been caused by certain errors that I hadn't compensated for. One of these may be that the car in this image may have been travelling at faster speed than in the image before, causing more motion blur. Another reason might be that the difference in car shapes; a side effect of this 'Ford Fiesta' having a longer shape may be that there is a larger surface area in motion to cause a motion blur. Another error that may have contributed to this anomaly is the shaking  effect that may have occurred due to operating the camera by hand. If I was to improve on these mistakes, firstly I would ensure that the car I am using as my subject, is travelling at a pre-set speed for all three tests when the image is taken (i.e. Having the driver of the car travel at 20 mph whilst the tests is being carried out). Additionally, next time I could carry out these tests using the exact same subject to eliminate errors that might be caused by differences in the drivers/cars (i.e. Getting the same person to drive the same car). Lastly, to minimize the errors, next time I would make use of a stationary tripod to ensure that the camera is stabilized , and thus will eliminate the risk of unstable hands affecting the final image. This would work especially well, in videos where the camera is required to pan in a stable manner.

For my third and final example, I chose to again increase the shutter speed of the camera to a relatively fast rate (1/100th of a second). The results I would be expecting to see from my final test would be a crisp image with minimal signs of motion blur. Similar to a freeze-frame.

Just as I has previously predicted, due to the shortened time span the shutter was allowed to remain open for; disallowing as much light to enter the camera lens, the car in motion in this image is not noticeably motion blurred.

During the process of carrying out these tests, I feel that I was able to partially familiarize myself with balancing the aperture, ISO and shutter speed to aid me in achieving the type of image I am looking to capture. I am now more confident in sacrificing one of these three features; whether it be to lower the ISO to reduce grain, thus adjusting the shutter speed and aperture to achieve adequate exposure, or slowing down the shutter speed to increase motion blur, I believe I am now comfortable enough adjusting the settings to suit the image I am after.