Foto 101.1 – Exposure

Exposure is in essence, the actual act of “taking a picture”.  What you are doing when you click the button, is exposing the film (or digital sensor) to light.  More specifically, you are exposing the film to the scene, and the light that reflects off of that scene.  If your settings allow for too much light you get “Over Exposure”.  Not enough and you get “Under Exposure”.  Get it just right, and you have a nice even exposure.  Here is a side by side comparison.  Not the best photo so just ignore that please   Also, note that this is just an example of what the camera decided was “proper” and your screen could show different.  It’s just to illustrate the point.  Personally I would like the “proper” exposure to be a tad brighter and more contrast…

The exposure, or amount of light that hits the film, is determined by three factors.  Two are functions of the camera, and one is all about the film.  Shutter speed and aperture are mechanical functions of the camera and are typically the bare minimum settings you will find on older film cameras.  Shutter speed is basically the amount of time, that the film is exposed to the scene.  Aperture, is a hole in the lens, that can be adjusted to let in different amounts of light.  So you can adjust the amount of light that hits the film in measures of both time and amount.   These two settings work in tandem, and thus there is more than one way to get the same exposure level.  You could take a longer shot with a smaller aperture(larger F-stop) OR you could take a faster shot with a larger aperture (smaller F-Stop) but each method has its own distinct differences depending on WHAT you are taking a picture of.  I won’t go into that now, see more in the Shutter Speed and Aperture posts.

The third thing that affects exposure, is the film itself.  Film is rated in “speeds” on an ISO scale.  ISO just means International Standards Organization, and they have a scale for rating speed of film.  Now, I get more detailed about this in the ISO post, but for now just know that the higher the speed of your film, the more sensitive to light it is, and therefore the less light you need to properly expose that film. This will directly affect your other settings because less light means shorter shutter speed or smaller aperture or some combination thereof.

I know it sounds confusing, but once you start “doing” instead of reading it becomes very simple.

Hope this helps, more Foto 101 to come soon!  Next up, aperture.  Stay tuned.

MV

Tagged as: Exposure, Foto 101, Photography Lessons, Quick Tips