Ad-hoc Photo Lesson 1: Exposure is like pouring a beer (2009.01.29)

So I realize this isn't my normal style, but I spent some time trying to put these analogies together to help Chris (Merri Donovan's little bro), so I figured I might as well share them since a lot of people ask me to help them with their photography. Chris ironically is taking photography classes at MSU-Bozeman, where I did a little bit of film school.

So here is the ad-hoc photo lesson #1 I gave Chris:

"The Basics:

Exposure - on Merri's Nikon camera (8008) its when the meter is a
"0" and basically its a balancing act of how much light you've let hit
the film. I like to think of exposure as a glass of beer. I want to
fill the glass to be full, but I don't want over pour. I basically have
two variables when filling my beer glass: how wide my tap (aperature -
f/stop) is and how long I let the tap run into the glass (shutter
speed). With a smaller tap I can let the beer run longer before it
fills and with a larger tap I can let it run less time. There is nearly
an infinite combination of tap sizes and run times that will give me
the perfect pour...the only reason I would want to choose between these
different fills is that the size of the tap and the amount of time I
let it run can effect the quality of the beer (photo).

Aperature/F-stop
- The tap. The smaller the f-stop number the bigger the aperature in
your lense is, thus letting in much more light. F-stop has a large
effect on depth of field- how many things are in focus in the
photograph at various distances away from you. If your taking a picture
of say the duck pond by the media building and you frame it up so the
pond is in the foreground and the building in the background you could
take 2 separate photos and see this difference. A 1/60 with f/22 you'll
see everything in crisp clear focus - the pond and the buidling in the
background. A 1/500 F/5.6 you notice that the pond is in tight focus
but that the lines on the building are slightly out of focus. The first
photo, the one taken with f/22 has more depth of field.

Shutter
Speed - Duration of the Pour. The faster the shutter speed the more
you'll be able to pause action. Shooting a snowboarder coming off a
jump at 1/2500 of a second will pause them in the photograph, they will
be completely stopped in the image. However if you shot this same photo
with 1/60 of a second the snowboarder would be a blurr, because in that
1/60th of a second they have moved from one location in your frame to
another and the film captured all of it. A key thing with shutter speed
is to always shoot at 1/60th or above if you are going to hand hold the
camera. The vibrations from muscle twitches in your hands will cause
images to turn out blurry with anything beneath a 60th of a second.

Film
Speed - The size of your beer glass. the 400 ASA/ISO film you have
relates to the sensitivity of the film to light - how much light is
needed to fill it up. 800 ASA film is a lot more sensitive to light
than say 100 ASA film. Think of 800 ASA film as a taster glass compared
to a 100 ASA pint glass. This means that if you were shooting something
with a shutter speed of 1/60 and an aperture of F3.5 with the 100 ASA
film, you could shoot with 1/500 and an aperature of F3.5 with the 800
ASA film, because it take less light to hit the exposure (glass being
full). The problem with higher ASA films is that they get grainer as
the sensitivity goes up and this is mainly because there is just more
light sensitive emulsion on the film.

If you can master these 4
concepts you'll do just fine with the technical side of photography and
then the other thing you have to start to learn is composition, but
that will be easiest to talk about once I start seeing images of yours.
"

Feel free to ask questions on techniques, etc., and of course I'm always up to critique images too. Learning is a constant process and works from both sides of the tab