Vision and composition, 1

I really only began studying photography about 18 months ago when my wife bought me a Nikon D50 for Valentine's Day. Before that, the only art classes I took were in grade school (if you can call them art classes). So to try to improve my photography skills, I've been reading art and photography books, learning a lot from people at ipernity and my local camera club, and signed up this summer for a photography class called Vision and Composition. It was held at the Maryland Hall for the Arts and taught by artist-in-residence and long-time photographer Dick Bond. (There was a recent story on him here: www.hometownannapolis.com/cgi-bin/read/2008/06_22-34/LIF.) These are my notes of this very interesting course, which met for a few hours at a time, once a week (next week is the last class). The notes will be split into two parts. The first day had a lot of lecturing. The others were mostly discussion and looking at photos taken by the class members. I learned a lot from the exercises and really enjoyed the class. I hope some of you enjoy reading these notes and that these can maybe spark a discussion of art/photograph classes you've taken or some positive learning experiences you've had with photography.

I alone am responsible for any mistakes. Please email me or add a comment if you see anything wrong. Feel free to distribute these (license: CC, Attribution + share Alike, as usual).

Day 1

What makes pictures succeed or fail? I don't believe there are rules for composition in photography. It is primarily a visual art. Thinking can get you into trouble! For example, do the "photo dance" (which DB demonstrated by looking into a camera rangefinder and shifting back-and-forth, front-to-back) to frame the shot properly; this is not a "thinking" activity. Photography is not an intellectual  exercise in composition rules, rather a vision-based art. Cameras don't take pictures, photographers do. Knowing the details of the camera's engineering or the chemistry of film emulsion will not help you take better pictures. You must learn how to visualize.

This course will involve exercises in "seeing''. What do we see when we photograph?
 

Light and exposure

You must be aware of light and its peculiarities. How does light work?

Physists tell us that light is both a particle and a wave. This means we can think of light eminating from a candle (the light source) analogous to a pebble being dropped into a still pool of water. Think of the ripples causes by the pebble (light source) as the light waves.

 If you have an SLR camera then after the lens, you have a mirror which must capture the light you want to record for your image. You can see that if the mirror is near the light source then it will capture a higher percentage of the photons that if it were farther away.

When you double the distance form the light source, you quarter the intensity. It satisfies the inverse square law: the intensity is proportional to the inverse of the square of the distance from the light source.

It is hard to visualize light exposure because our visual system has a very sophisticated autoexposure system which corrects for dimmer light by dialating the pupil.

Focus

Our two human eyes focus much better than one camera eye. For example, cover one eye, place two fingers 6 inches from your face and look at me between your fingers.  One is out of focus - me or your fingers. On the other hand, if you use both eyes and just look around, everything is in focus! As anyone who plays a sport such as tennis or racketball knows, the focusing ability of our vision system is remarkable.

The human eye has a lens at the front and retina at the back. The brain compensates for the effect that any lens has in inverting an image. The SLR camera's eye is analogous. The mirror just behind the lens flips the image horizonally (flips top-to-bottom). The pentaprism in front of the eyepiece (at the top of the camera) flips the image vertically (flips right-to-left).

How do you improve focus of a far away object? You squint, or narrow the opening of the eyelids. Decreasing your camera's aperature has a similar effect.

On the camera's film or sensor, images which are out of focus appear as circles. The depth of field is the range of distances which are rendered in the camera in focus. The focal length of a lens is defined to be the distance between the lens and the plane (in front of the camera) of sharp focus. The larger the focal length, the more area can be captured in the camera. The smaller the aperature, the more objects in the image are in focus.

The lens aperature is the diameter of the lens opening divided by the focal length of the lens. A relative lens aperature of 1/N is written f/N. The number N arising in this way is called an f-stop (or f-number). The larger the f-stop, the smaller the aperature. For example, the close-up of an image taken with f/2 has all the objects in the background out of focus. However, a photograph taken with f/20 might have all objects in the image appearing in focus.

Shutter speed: Aperature and shutter speed settings are used together to control the amount of light from the subject that reaches the film/sensor. The formula for the exposure is exposure = (intensity) x (time), or E = I*t. Here the time t is measured by the shutter speed.

Exercise

Take 20 images. All must be completely out of focus. Show courage - take color abstracts with nothing even close to being in focus. You will realize how different the eye and the camera imaging system are.

Using motion blur on some shots is okay but you must also get some shots with "genuine circles of confusion''. No computer manipulation allowed! Prefer that you don't even look at the images on the computer before class!