Creating photographs, at it's base, is simply the act of using a camera to record light that is reflected off of your subject onto film or a digital sensor. At the core of it all, that is really a cameras only function - capturing reflected light and storing it as a snapshot of time.

This tutorial is going to discuss the three methods your camera has of controlling the amount of light that is captured on it's sensor or film in order to make an exposure and to some degree what creative effect the use of each method has on your final image.

As you might have guessed by the title of this post, the three light controlling methods are: Aperture, Shutter Speed & ISO.

Some may recall that I am on a mission in life to get people to learn to take photographs with their camera and stop letting their camera take pictures for them. I'll bet that most people are generally unfamiliar with the shutter, aperture and ISO (or film speed for you non-digital folks) and how they can be used to control exposure because they have locked their camera into some automatic mode and expect it to make all the decisions about these parameters for them - but how can the camera know what you're trying to accomplish when creating a photo? So again I challenge you all to put your camera on Manual mode for a while (often listed as 'M') and let's have some REAL fun!!

Now that you know the names aperture, shutter and ISO let's see if we can define those terms a bit for the uninitiated.

Aperture is a measurement of the size of the diaphragm opening in your lens through which light is allowed to pass to the sensor. Naturally, the larger the opening, the more light that hits the sensor. Thus controlling the size of the aperture allows you to increase or decrease the exposure of your image. Aperture is interesting because it is expressed in terms of f-stops such as f/2.8, f/4, f/5.6, f/8, f/11, f/16, etc. f/2.8 represents a wide opening which lets in more light, while f/16 represents a small opening which lets in less light. The steps listed above are all representative of one full f-stop, though most cameras allow for additional steps in between the full stops. Increasing or decreasing one full f-stop means a doubling or halving of light, so for instance f/4.0 will allow half the light that f/2.8 does and also f/4 allows twice the light that f/5.6 does and so on.

Shutter speed (more accurately referred to as 'exposure time') is a measure of how long the shutter curtain within the camera body remains open to allow light from the lens to pass through to the sensor. Similarly to aperture, the longer the time, the more light passes through and the shorter the time, the less light. Shutter is expressed in seconds or fractions of a second such that the f-stops for shutter speed are 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000 and so on. Again the f-stops work the same as for Aperture and ISO so that 1/1000 allows half the light that 1/500 does and 1/60 allows double the light that 1/125 does.

ISO is a measurement of the light sensitivity of your recording medium (film or digital). In the film world if you were going to be shooting in a condition where there was not a lot of light, you would need to load a high ISO film into your camera; digital cameras allow you to change the sensitivity of the sensor directly through a menu or button on the camera. In either case, higher ISO equals greater light sensitivity (more light in your photo) and lower ISO equals decreased sensitivity. Full ISO stops generally go 100, 200, 400, 800, 1600, 3200 and so on.  

So these are the options you have at your disposal to control your exposure. All three work in tandem and can be used to create various effects or desired results in different situations.

You may go outside on a bright, sunny, cloudless day and set your camera shutter to 1/125 with an f/16 aperture and ISO 100 and that will usually give you the right amount of light for a nicely exposed landscape style shot. It's important to note that these values only represent how much light is being recorded by your sensor and many times, for creative reasons you may want to change the values while still keeping the same overall exposure.

Let's say you're not shooting landscapes on that bright day, but its a sporting event and you want to 'freeze' the action of the players. A shutter speed of 1/125 is not a short enough duration to freeze people running so you'd want to increase it to at least 1/500 to prevent any motion blur. Of course while the change in shutter speed may freeze the players motion its also letting in about two stops (or four times) less light; to get the exact same amount of light you'd then need to adjust your ISO or aperture to allow two stops more light. I'd change the aperture in this case and for sports I might set my camera to a shutter speed of 1/500, with an aperture f/8 and ISO 100. Keep in mind that 1/500, f/8 @ ISO 100 will allow the same exact amount of light to expose your shot as 1/125, f/16 @ ISO 100, but now you've made a creative decision to give you what you want in your final photo - something which your camera could never do for you on it's own!

Those are the basics, take some time to play around with your camera's manual settings and see what more you can learn! Some final things to keep in mind about these settings is that there are trade offs involved with most of them. Here are the major things to conside:

Aperture - when using a wide aperture (say f/2.0, f/2.8, etc.) the depth of field, or area that's in acceptable focus will become shallower. When using a small aperture (f/16 or more) you begin to run into a degradation of the image quality due to the phenomenon of diffraction.

Shutter - With very slow shutter speeds, say 30 seconds or more, there can be 'noise' present in dark areas of the image, particularly with digital cameras. There arent any image quality issues with using faster shutter speeds that I am aware of.

ISO - the higher the ISO, the more noise or graininess will be present in an image, most SLR cameras today should work reasonably well up to about ISO 800, though some of the more recent technology allows shooting usable images up to and beyond ISO 6400. All things being equal ISO 100, 200 & 400 should be where your camera stays until you simply dont have enough light gathering options from changing only shutter and aperture.

When people come to me and ask about how they can improve their photographs there are many things that come to mind, usually I give some advice about light quality or good focusing technique and then after the conversation I think to myself 'I really should have told them about the importance of perspective!'

You see, there are many different elements that can go into the creation of a visually interesting photograph such as:

Light - color, intensity, quality & directionality all greatly influence the final image

Composition - the placement of your subject within the frame and the consideration of foreground and background elements are key aspects to consider in any photograph

Depth of Field - discussed in a previous tutorial post, DoF manipulation has the ability to tranform an image in many ways

Color, Texture & Contrast are also relevant tools that a photographer has at their disposal, its the manner in which these elements and others are combined to create an image that make the image more or less appealing to the viewer.

As you might have guessed by the title of this post, there is another major element of photography that is often overlooked but is no less important and which has the potential to be VERY impactful, it is known as Perspective. There are a lot of different ways that your perspective can be used to add a little pizzaz to an otherwise ordinary image, but before I get too much into that let me explain a little about why I believe the use of perspective is so effective!

I've given this a lot of thought and I really believe that people are used to seeing things the same way most of the time - from their normal eye level with a pretty standard viewing distance. When you actually change the perspective from eye level to something above or below or to something much closer or farther than the usual viewing distance, you immediately increase visual impact of a photograph.  

Sounds simple right? Well it is - but it's just not always easy. Shooting like this often means you can't be no punk! as my uncle used to tell me...sometimes getting a different perspective that works means you gotta get down on the ground or climb up in a tree or whatever, you can't be scared of a little extra effort or perhaps a bit of dust on your pretty new trousers.

With all that said, lets talk about using perspective artfully to enhance your photos and increase your storytelling abilities. As I said there are many different ways to use perspective - you've probably all seen the examples where someone in the foreground appears to be 'holding up' the leaning tower of Pisa, which is really off in the distant background - that's known as 'forced perspective' and is just one way to make creative use of the tool in photography.

I've pulled together the following samples to help illustrate my point about the use of perspective:

Here is a low angle which creates an unusual view of a loving couple - this shot benefits from an even more dramatic view because of the use of a wide angle 14mm lens in conjunction with the extremely low camera position.

Another exreme low angle gives a different than normal view that uses leading lines on the road to also draw the eye in to the group

Here are two samples of closer than normal perspective, one from a high angle as well, which I think adds intimacy to the photos.

In this photo of Tameka the camera is tilted to slant the horizon and give a humorous photo a little more impact, note that this horizon tilting effect would not have been possible in this case without also using a low camera perspective.

This is another sample of a high angle, I picked this photo because it's a good example of a view that most would otherwise never see of the couple dancing and that makes it more visually appealing in my opinion.

Finally, note that low angles are usually the best way to photograph small children - if you try shooting them from an adult perspective the resulting photo generally loses a lot of it's impact - partly because when you look at the picture, once again you are seeing them exactly the same way that you always see them!

So hopefully this has been a little food for thought, if nothing else maybe some of you fellow parents will grab your cameras, then get out there and get on your knees once in a while for a brand new perspective on your young ones.

Anyone interested in sending me some samples of their interesting perspective photos to be featured here on the blog for a follow-up post feel free to do so - just click the 'contact me' link and attach the photo to your email message along with a description of the shot.

Now get on out there and shoot someone! :)

In trying to determine what the next blog tutorial should be about, I was really having trouble. The problem was I kept thinking in terms of chronology - what would people best need to know after reading the last tutorial? But now I've come to the conclusion that I will just share whatever is in my head asking to come out when I sit down to write - today that thing is a photographic concept known as 'Depth of Field'.

The term 'depth of field' or DoF for short should be well known to anyone who's been shooting for a while but though it's not a TERRIBLY complicated concept to grasp, I find that some of my friends and peers occasionally struggle with the application and control of DOF, which is a shame because it's a factor that has the ability to dramatically transform a photo!

So for the uninitiated, the next question I guess must be WHAT THE HECK IS DoF ANYWAY??

In basic terms, DoF can be defined as the amount of an image that is within 'acceptable focus'. I make every effort to write these tutorials in such a way that people with many different levels of photography skill can gain something from them, so without being terribly technical this description should suffice - I'm guessing no one reading this wants to hear me get into discussions of the 'Circle of Confusion' or lens mathematics!

With all that said, the next questions must surely be WHAT DO YOU MEAN BY 'ACCEPTABLE FOCUS'? and HOW CAN I CONTROL THE DoF??

I'm glad you asked!

First of all let me explain acceptable focus - this is a discussion that could go on for a while actually, so I will try to bake it down to the bare essentials for the sake of all our sanity. Strictly speaking, in any given photo there can only be ONE point which is properly focused and everything else is either in front of or behind that focus point. To the naked eye however the distinction between in and out of focus is not always so readily apparent, as an image shot with a large DoF will have more elements that 'appear' to be in focus from foreground to background, while an image shot with a very small DoF will have only a small portion of the overall image in focus.

Controlling the DoF in your photos is yet another topic where the discussion could go on and on, but for simplicity's sake allow me to simplify it for you, oh faithful reader :). The primary methods for controlling DoF that you should be concerned about are lens aperture and subject-to-camera distance.

Lens aperture refers to the size of the opening in your camera's lens through which the light enters to expose your photo. The smaller the opening, the greater the DoF, the larger the opening, the smaller the DoF. Before moving on, please go back to the previous sentence 3 times and read it out loud.

No, really. Go back and read it...

Yes, OUT LOUD! :)

Ok, so here's where it gets a little tricky for some people because controlling the aperture setting on your lens means setting a number which is basically the inverse of what I just said. What I mean by that is, a lens aperture of f/2.8 - a small number - is actually a LARGER opening (meaning lets in more light and causes a shallower depth of field) than an aperture of f/16 for instance.

BTW controlling the aperture generally requires setting your camera to manual (or aperture priority), otherwise your camera will decide for you what the aperture should be...where's the creativity in that? How would your camera know what you're trying to do anyway? Aren't you reading this because you want to start taking better photos and stop taking snapshots?? Be forewarned - we're going to slowly wean you off of the automatic stuff around here...

The second method of controlling DoF is 'subject-to-camera distance', this is not terribly technical and requires no fumbling around with your camera manual at all, its just like it sounds - move closer and get shallower DoF, move farther away and get a larger DoF.

So here are a couple of examples of shallow vs. large DoF in application, in this first photo the aperture used is f/1.2, which is the largest aperture available in 35mm lenses today. Notice how the potentially distracting background foliage turns into a rather pleasing blur (this blurred background is known as 'bokeh') and makes the subject stand out in the photo.

In contrast, the group photo below would suffer from a shallow DoF as some of the individuals would be difficult to identify, so clearly a much smaller aperture than f/1.2 is called for to provide the greater DoF. In this case I chose an aperture of f/9 and a longer subject-to-camera distance to render all the faces within 'acceptable focus'.

This is just meant to be a primer, something to get folks out there to take off the training wheels that are the automatic camera settings and play around with being more creative and deliberate with their photos. There are lots of things omitted here, most of which I intend to address in future editions of our tutorial series but for any of our faithful readers who would like to continue the discussion or have questions that just can't wait, I am always available to share what I know - just contact me via email anytime.

In the meantime, keep shooting people!