Understanding Exposure

During the meeting there were a few people that claimed that they were still struggling with the concept of Exposure.... specifically Aperture and Shutter Speed.  So I thought I'd write a very small introduction and point you to a site that has some very good discussions about Exposure.  They use several good metaphors to help us get our  heads around this subject.

Actually there are three apsects of Exposure to consider, the third is ISO (film or sensor sensitivity).  It is the relationship between Aperture, Shutter Speed and ISO that create the desired exposure  You should think of them as creating a triangle.

I'm begining to think that the use of automatic cameras can imped our understanding of exposure. If you have a DSLR go manual or pick up an older functional film camera that allows you to go manual, you should play with these settings and see how they interact.   Even many small "point and shot" cameras allow you to adjust a few of these settings, give it a try.

In a consistent light select a subject and adjust any one of the aspects of the exposure and see what you have to do to the other two settings to get back to a good exosure.  How do you have to compensate the shutter speed or aperture should you change the ISO, etc. Then change the aperture and see what you have to do to either the shutter speed or ISO to get back to a properly exposed shot.  In some lighting environments you might have to adjust both settings.

I'll go no further here and send you off to the "Digital Photograph School" for your first lesson in exposure.  On their page they have additional links that discuss Aperture, Shutter Speed and ISO separately.  Enjoy!