Archives for Photography 101 category

When I first started taking my camera off automatic and manually adjusting the settings to take more control of my photography one of the main principles of photography that I struggled with was aperture.  In fact, although the more I shoot the more I understand aperture, I have not yet reached the point where it is second nature.  I often have to recite to myself “large number, small opening, small number, larger opening.”  I’m sure I am not alone in this so I have put together a relatively simple explanation of aperture.

Aperture Defined (Officially)

According to the definition of aperture is as follows:

ap·er·ture (āp’ər-chər) – noun – a : the opening in a photographic lens that admits the light b : the diameter of the stop in an optical system that determines the diameter of the bundle of rays traversing the instrument

Aperture Compared to the Human Eye

That definition is a bit cumbersome, but one of the best comparisons I have found to help understand aperture is to the human eye.  The iris of your eye regulates how much light is let in for your brain to decipher what you are seeing.  In a dark setting your iris opens up to let more light in.  In a bright setting your iris closes down since not as much light is needed to see your surroundings.

The aperture of a camera works in much the same way.  Your camera (you) has a lens (your eye) with a diaphragm (your iris) that opens and closes based on the the lighting (either automatically by the camera or manually by the photographer) in order to regulate the amount of light that reached the film or sensor (your brain).  Obviously in your camera, unlike in the human eye, there are other factors that work with the aperture to control the exposure such as shutter speed and ISO, but the basics of aperture by itself are much like the eye.

f-stop and the Lens Opening

With the basic definition in mind, there is one significant and often difficult to comprehend, aspect of aperture that you are going to need to understand to master it.  That is the f-stop numbers and how they relate to the size of the opening in the diaphragm.  As the diagram below shows the larger the f-stop the smaller the diaphragm opening. That means you have to think opposite of what seems “normal.”  To let less light in you need a bigger f-stop which results in a smaller opening.  To let more light in you need a larger f-stop which results in a bigger opening.

Large f-stop = Small opening

Small f-stop = Large opening

Diagram of standard aperture f-stops

How to Adjust Aperture

Each camera model is going to be a little different.  But in general, you have about four options for setting aperture.

  1. Fully Automatic – the camera determines the optimal settings based on the lighting conditions and sets both the aperture and shutter speed.
  2. Fully Manual – Usually denoted by an M on the exposure mode dial.  You select both the aperture and shutter speed yourself to obtain the exposure you are going after.
  3. Aperture Priority – Usually denoted by an A or Av on the exposure mode dial.  You select the aperture while the camera sets the shutter speed.
  4. Shutter Priority – Usually denoted by an S or Sv on the exposure mode dial.  You select the shutter speed while the camera sets the aperture.

A typical range of f-stop of aperture values

Possible f-stop ranges

What is Aperture Used For?

Aperture impacts two closely related aspects of your photography, the exposure and depth of field.  For the exposure you need to remember that it is dependent on more than just aperture.  Shutter speed, film speed (ISO) and aperture play a role in determining a good exposure for an image and the three are closely related.

Aperture + Shutter Speed + ISO = Good Exposure

Aperture also plays a role in depth of field. The more you open up your aperture (the smaller the f-stop number) the more shallow your depth of field will be, i.e. your focal point will be in sharp focus while the foreground and background will blur.  Conversely, when you close down your aperture (a larger f-stop number) the depth of field will be greater.  Both the subject as well as the foreground and background will be in focus.

As with learning anything in photography, the key to mastering aperture is to experiment with it.  Try using the various exposure modes on your camera (other than automatic), bracketing with the aperture, and seeing the effects of using a large aperture and a small aperture on the same subject.  In time it will become second nature.

I must admit depth of field has been a fundamental photography concept that has been difficult for me to master.  Although I am far from mastering it I have managed to take the first step, which is understanding it.  So I figured I would give the “Cliff Notes” version of depth of field for anyone else who is struggling to understand it.

What is Depth of Field?

Depth of field refers to the portion of an image that is in focus or sharp.  It is a great tool to tell the viewer what part of the image is most important by only having that part in sharp focus.  It is generally divided into two categories; narrow or shallow depth of field and great depth of field.  Narrow or shallow means that a very limited (or narrow) part of the image is in sharp focus and the rest of the image, in front of and behind the main subject of the image, is blurred.  Great depth of field is just the opposite.  A greater portion of the image including the space in front of and behind the main subject is in focus.

How do you control depth of field?

There are three factors that affect the depth of field of your photograph.

  1. Aperture Size
  2. Focal Length
  3. Lens-to-Subject Distance

Aperture Size

Put simply, the smaller the aperture (the larger the f-stop #) the greater the depth of field and the larger the aperture (the smaller the f-stop #) the shallower the depth of field.  So if you have three objects lined up at varying distances from each other and you want to capture the front object in sharp focus while blurring the others open your aperture way up to whatever your smallest f-stop is for the focal length you are using (f/5 for example) and focus on the front object (top photo below).  If you want all three objects in relative focus close your aperture down to your largest available f-stop (f/22 for example) (bottom photo below).

Example of Narrow Depth of Field Photograph

large aperture/small f-stop = shallow depth of field

Example of Great Depth of Field Photograph

small aperture/large f-stop = great depth of field

Focal Length

Shorter focal lengths lenses result in a greater depth of field while longer focal length lenses result in a more shallow depth of field.  For example if you are using a 35 mm to 70 mm zoom lens and focus on your subject at 35 mm with an aperture of f/8 you you will get your subject as well as more of the foreground and background in focus (top photo below).  Then when you change the focal length to 70 mm at the same f/8 aperture the resulting depth of field will be narrow, meaning a blurred background and foreground and sharper subject (bottom photo below).

Example Photograph with Great Depth of Field

short focal length (~50 mm) = great depth of field

Example Photograph with Narrow Depth of Field

long focal length (~200 mm) = shallow depth of field

Lens-to-Subject Distance

The further you are from your subject the greater your depth of field will be.  Conversely, the closer you are to your subject the more narrow your depth of field will be.  For example, taking a photograph of a group of people in front of a scenic background from 20 yards away will result in both the people and the background being in focus.  While moving closer to the people, say 5 yards, will result in the people being in more sharp focus while the background begins to blur.

further away from subject = great depth of field

closer to subject = shallow depth of field

In film photography ISO refers to the film’s sensitivity to light and is also called the film speed.  The chemical makeup of the film is altered to either increase or decrease its sensitivity and speed.  The lower the ISO number the slower and less sensitive the film is to light.  Low speed film also results in less grainy photographs.  The higher the ISO number the faster and more sensitive the film is to light.  In simple terms that means in well lit situations, such as outdoors on a sunny day, you need a lower ISO film such as an ISO 100 and in less lit situations and action shots, such as indoors and sporting events, you need a higher ISO number such as 400.

So this may lead you to wonder why there is an ISO setting on your digital camera.  There is no film to chemically alter and you either set it and forget it on auto or manually adjust your shutter speed and aperture to compensate for different lighting conditions and motion.  So how does ISO fit into digital photography?

In a digital camera the film is replaced with the sensor.  So ISO in a digital camera sets the speed and sensitivity to light of the sensor.  Being able to adjust your ISO allows for expanded shooting options in different conditions.  For example, if you leave your ISO on automatic the camera will, in most cases, chose a low ISO.  In daylight conditions this will probably be acceptable.  But in low light conditions you will need to compensate by extending your shutter speed or opening up the aperture.  But a longer shutter speed can lead to camera shake and blurry pictures unless a tripod is available.  So an easy solution is to increase your ISO.  The faster “film” speed and greater sensitivity to light allows for shorter shutter speeds and less chance of blurred pictures from camera shake.

You will want to keep in mind that the higher the ISO the more noise a digital image can have (grain in film photography).  Depending on the end use and final printed size of your image this may be an acceptable compromise to get the shot you want.

I shot the three photographs below in Scottsdale, AZ.  The ISO setting from left to right was 100, 200 and 400.  The aperture was at f/6.3 and the shutter speed was at3.2 sec for all three.  As you can see, increasing the ISO allowed for the more sensitive sensor to take on more light and get a very different picture.

Night Phtograph Shot at ISO100 Night Photograph Shot at ISO 200 Night Photograph Shot at ISO 400

Click on the images to see a larger version.  Then go out and take your camera off ISO auto and experiment.

The more I photograph the more I notice my surroundings in a very different way than I ever had before.  I am always on the look out for the next great photo opportunity.  (Makes for a bit of distraction while driving)  As I am scoping things out for photograph opportunities there are several key things that I particularly pay attention to because I feel they are important to great photos and improving my photography skills.

  1. Light and shadow in photographyLight and Shadows – I look at how the two work together.  Time of day plays a significant role in this because the two change constantly throughout the day.  A spot that may have great light and shadows at 8 am can be a whole different story at noon.  Morning and late afternoon/early evening light is often (but not always) best.
  2. Patterns – I find myself really stopping and looking at the details ofRepeating patterns in photography everyday things.  There is pattern everywhere; the grill of a car, a fence line, the branches of a tree.  Repeating lines, patterns and circles frequently make great photographs when composed right.  I will look at things close up and from a distance as well as check them out from different angles.  My goal is to see how they change depending on my position and view.
  3. Texture – Texture is more than just how something feels.  It ties into pattern and light and shadow as well.  This is another Texture in photographyone where I really try to pay attention to the details.  Most of us tend to overlook the texture of most of the things in our everyday lives.  I find myself looking at things like the bark of a tree and how the texture works with the light and shadows.  Or a brick wall.  Close up shots of things I may never have thought of before can often reveal a great photograph.  Taking the time to study the details of things and finding the best composition to lay the photograph out has helped me quite a bit.
  4. Lines – Lines are everywhere and I always took them for Repeating lines in photographygranted.  But they can often times make or break a photograph.  In photography you hear all kinds of terms like leading lines, converging lines and the like.  They are more than just buzz words.  One thing I have done is to make sure I am checking things out from multiple angles.  I get down low and when possible up high.  The lines change dramatically in some cases.  Look for lines from objects as well as their shadows.
  5. Colors – This one seems obvious.  But it is more than the pretty Use of color in photographyred flower.  I look at how the colors work together or sometimes don’t work together.  I have found amazing color in the least likely places or places I usually take for granted.  I am forcing myself to think beyond the obvious color and playing with color.  A hint of orange makes this a very different picture than it would be if it was not there for example.

Up until recently I did not pay much attention to the fundamentals of photography.  I shot what i liked and tried to be artistic and creative with it.  But I did not know much about aperture and shutter speed or composition (still have a lot to go on that one) or the equipment I was using.  As I get more serious about photography and am trying to continuously improve and take my photography to the next level I am getting more into the nitty gritty.  So I am reading, surfing the Internet and finally taking an introductory course to digital photography at a local community college.

I’m sure I am not the only amateur photographer out there who has been winging it.  So I am going to pass along some of my “discoveries” through Photography 101 posts.  I do not anticipate that these are going to be life altering discoveries.  In fact they are the 101 of photography, the basics.  But sometimes we are so excited to get shooting we skip right past the basics.  Even though you may not need to (or want to) study every detail, I hope these are things that can help you improve your photographs as they are doing for me.

The first Photography 101 is on lenses.

DSLR Lens Comparison ChartLenses fall into three main categories and are measured in focal length (although focal length is not the only characteristic you want to consider when purchasing a new lens).  The chart at the left outlines those three categories. But keep in mind that the “normal” lens can vary slightly and it is safer to say the focal length of a normal lens is about 5o mm and the wide and telephoto options fall into place accordingly.

Normal is called such because it is considered the lens that is as close to what the naked human eye would see, about 50 mm.  A normal lens is typically a prime lens meaning that is has a fixed focal length without zoom capabilities.  Some of the advantages of such a lens are that they are generally cheaper and produce a slightly better quality picture.

28 mm Prime Wide Angle LensWide angle lenses have a large depth of field making it easier to have both the foreground and background in focus.  They also, as the name implies, present a view that is wider than normal.  With focal lengths less than 50 mm, 28 mm is considered a standard wide angle lens.  24 mm and 35 mm lens options are also common.  Fish eye lenses also fall into the wide angle category.  Although it is an extreme wide angle that does not correct for distortion.  You have probably seen these images that are often times circular.

Super-telephoto-600mm-lensThe final category is the telephoto lens.  Lenses with a focal length greater than 50 mm (give or take) fall into the telephoto category.  Standard telephoto lenses will usually fall between 80 mm and 130 mm.  Medium focal length telephoto lenses will usually fall between 135 mm and 300 mm while super telephotos can be found all the way up to 1000 mm.

A few other terms to keep in mind:

prime – a prime lense can fall into any category.  It simply means the lens has a fixed focal length.

Image of Sony Alpha 18 mm - 70 mm DSLR lenszoom – It is often confused with telephoto, but zoom and telephoto are not one and the same.  Zoom means the lens has a focal length range, in contrast to prime, allowing you to zoom from one focal length view to another.  For example my 18 – 70 mm lens lets me zoom between an 18 mm wide angle view and a 70 mm telephoto view.  Any category can have zoom lenses and they can cross between categories.

Here are the lenses I currently own:

  1. 18 mm – 70 mm
  2. 28 mm prime wide angle
  3. 100 mm – 300 mm telephoto
  4. 28 mm – 90 mm

I am hoping to add a 500mm telephoto soon.