Shutter speed: in depth

The shutter on a camera is a sophisticated piece of electronics that precisely controls the amount of time the sensor is exposed to light.  The duration for which the shutter remains open is called 'shutter speed'. In photography speak, shutter speeds are said to be fast (shorter duration) and slow (longer duration). A shutter speed of 1/200 seconds is faster than a shutter speed of 1/60 seconds  (remember fractions :)).

"Clicking" activates the electronics that controls the shutter. As soon as the shutter is open, ambient light starts accumulating on the photographic medium (film or digital sensor) and continues to do so until the shutter closes again.  This means that by controlling the shutter speed we can make a bright, sunny day look grey and cloudy  (using a very fast shutter speed) or make a pitch-black night feel like dusk

Aperture: in depth

In a previous post, we talked about the function of the lens aperture; control over the volume of light that strikes the sensor.  A wider aperture will result in a brighter image compared to a narrower aperture.  Well, if a wider aperture results in a brighter image why don't we always use this, right?  There's a very good reason for this and it's called depth of field.

Give a little, take a little: reciprocity

Now that we know some of the basic controls available on your camera, let's try and understand how they relate to each other.

A correctly exposed image can be made using several combinations of aperture and shutter speed.  The relationship between the aperture and shutter speed that enables us to vary the settings and still maintain the same exposure level is called reciprocity. Each combination results in the same level of exposure but the aesthetics on the image will vary a great deal  (we'll talk about these differences in much greater detail in future posts).

Here's how reciprocity works.

The Basics

At its core, a photograph is a recording of light on a medium (film, sensor etc.).  When we make an image we try to manipulate the amount of light that strikes this medium. Some of this can be controlled on the camera while others are external to it; selecting the time of day to shoot, using reflectors and strobes to control contrast etc.

In this post we'll talk about three basic controls on a camera that every photographer needs to understand to get the most out of their exposures;  aperture, shutter speed and ISO.  Together these three variables make up the exposure triangle.  Develop and understanding for how they work and interact and you're off to good start.

The information discussed below is relevant to all types of cameras, DSLRs, point-and-shoots and mobile devices but the controls on point-and-shoots and mobile devices will be more restrictive. Here's an image of the info screen as seen on a Canon EOS 40D. There's lots of information here but in this post we'll focus only on the items that are circled.

Got Questions?

Thanks for attending the workshop on Saturday.  Please use the comments section to add any further questions you have.  I'll keep adding posts to this blog based on your questions.

A First Post

Getting started is hard...very hard.  So the few words that I type on this post carry a lot of weight.  It's one thing to have good notions and great ideas swimming in your head and totally different world getting even a small part of that implemented.  Here's to finally kicking things off.

This blog will focus on things related to photography.  We all need some place to start and I've decided to start with the mundane; discussions about photography technique.  The concepts are widely known among folks familiar with digital cameras but can be a little daunting when you first pick one up.  Hopefully, the information on this blog will help you understand and master your camera.  Over time this knowledge will bubble through to the back of your head, you'll be able to recall this information without a second thought.  Once you make it to this stage you'll be able to focus on the real reason you bought a camera; to make good images.

Do not mistake understanding your camera for understanding photography.  Digital cameras are gadgets that operate according to certain rules that can be mastered with a little bit of effort.  In most case you don't even need to know exactly how something works.  Photography, is a different beast all together.  We need to develop an understanding of light, of the subject we wish to shoot, of the situations we are in and above all a sense of how viewers perceive an image.  Consider that all these are subjective and you'll quickly understand why there's no easy recipe for a good photograph.

If you have any suggestions for making this site better, please let me know in the comments section below. Thanks for stopping by and thanks for reading.