LESSON 5: Depth of Field

I hope the last lesson about shutter speed, apertures and ISO's helped you understand how to use your camera more effectively!

For this lesson, it's time for Depth of Field - Even if you have never heard of this term before, chances are, if you have an SLR camera and a lens with a manual setting, you have most likely experienced what depth of field is about.

Here's a nice diagram to explain - squirrels, I'm not sure why, but it gets to the point!

Depth of field relates to the distance between objects in front of you.
For example, as my eyes are focused on the screen whilst typing this, my hands and keyboard are blurred and out of focus in my vision.
When looking at the keyboard, the screen then drops out of focus.  Same applies to the coffee cup sitting between the keyboard and screen.  As I move my eyes to it, both screen and keyboard are out of focus.

It really is that simple!

To purposely pinpoint a subject of interest in your images, you will use depth of feild to ensure that it is in focus, no matter where on the image it is located.  Center, top, left, or right.


To use depth of field to it's potential, aperture plays a part.  Here's a quick diagram....

How light effects your focus point

The smaller the F stop, the more light you are letting in; therefor, the more depth you will have to your image.  Your subject will be sharper, and you background, more blurred.

The larger the F stop, the less light is let in.  Giving you a flatter image and a lot more of the background in focus (as well as your chosen topic)


There are two categories within depth of field:

• Short depth of field 
• Long depth of field

Here's an example of short and long DOF (depth of field) I took last week when in France.  I used a 50mm Nikon lens with manual focus.  It has an aperture of 1.4 - which lets tons of light in.

Short Depth of Field - the ski is in focus and the background remains blurred.

Long Depth of Field - The ski is out of focus whilst the tree is now sharp and more background can be seen.

DOF is used in every photograph created!  So now you know, there is a term for what your point of focus is.
There is also a huge amount of numbers behind it.  Formulas, diagrams & mathematics - none of which I'm sure you will want to think about when you are out taking your shots.

It is an interesting read if you really want too, but you can certainly get out there and start applying depth of field more specifically without all the science!

DOF is a handy thing to consider when you are choosing a lens for a certain style of image.  I use the Nikon 50mm Manual focus.  This is great on non-moving objects, anything involving that you can take time to focus on works a treat with this lens.  Otherwise, an auto-focus is a bonus when capturing people and portraits in a busy, fast paced situation.
So have a think when you are expanding your gear as to what sort of images you want to create or what jobs you may end up taking on in the future.

Here's a few more examples from the snowboarding trip of Depth of Field! 

Ski poles in focus, soft background and foreground.

Long DOF - Fur toys in focus, background visible, but not sharp.

Very short DOF - Crystal clear subject up close, no focus on background at all

Depth of field in action again.

You can see the nice blur effect around the edges with this tighter shot.

Not too long and not too short, just enough to capture the subject without eliminating it's environment

'Yamaha' branding is the main focus point here

The Nikon 50mm is a great lens, pin sharp and lets in lots of light

That's all for the meantime on depth of field.  I may going more into the topic later on on another, more advanced lesson!  But for now, a short introduction is enough to understand the term and how it is applied.
I will have a lessons on lenses and how they work soon, this will also help with the more intense understanding of depth of feild.

Now get out there and give it a go! 

Photography LESSON 2: How Film Works

This is the second lesson in photography.  I am going to keep the lessons in order, running through all the processes involved in photography.  Hope you guys can learn something useful from it.

LESSON 2:

PHOTOGRAPHIC FILM & HOW IT WORKS

Centuries after the camera obscura was first seen, science had began to find it's way with certain chemicals that were found to be sensitive to light.  This was around the 1830's. 

The film we are familiar with today is made of a strip of plastic, coated with emulsion containing whats known as Silver Halides.  Silver Halide is made up of six different chemicals and, as a group, it creates a compound chemical that is light-sensitive.

Your standard 35mm film in canister

Layers of your black and white film

These silver halide salts are held in place by gelatin in each layer of the film.

Black and white film is usual more basic and made up with one layer of silver salts.

When you expose your film to the light, the salts are converted to metallic silver and a photochemical reaction takes place.  This is what creates you image onto negative.

Layers of a color film - each layer absorbs light as it is exposed when the shutter of your camera is opened.

 Thus, when you push down the trigger on your camera, the click you hear is the shutter opening for a fraction of a second to let light into your camera and to hit your film.

If you have read LESSON 1: The Camera Obscura section of my blog, this image below will be familiar to you.

This time, the wall the image is projected onto, is a small section of the film strip in your camera.

As your film is exposed to light, the chemicals soak up the light and create your negative image

I will talk more about film processing and how you get your final print in the next lesson section of this blog.  In the meantime, here is a bit of an insight on how film was created.

A Brief History of Film and Photography

The two big names in photographic history are British born, Henry Fox Talbot (who was seen as the pioneer of photography) and Frenchman Louis Daguerre.  Both were competing against each other in the 1830's in the race to see who could create an image with the abilities to be reproduced for the masses.

Henry Fox Talbot

 

Talbot used the large, shoe box style camera to create his images.  He discovered that paper could be coated with the silver salts and with several chemical reactions, the image could be 'fixed' and a permanent negative could be made.  This in turn, gave him the upper hand against Daguerre and his images which he fixed onto a silver-plated sheet of copper, much like a mirror- only producing a one of with each image.  These were often referred to as "The Mirror with a Memory" during the 19th century. 

Louis Daguerre

 There are many famous examples of images from both of these men.  Unfortunately for Daguerre, his methods were seen more as a brick wall for image making as he could not make reproductions of his images, unlike Talbot, who created the negative image with his paper and chemical methods.

Here are a few of those famous examples that shocked the world and were a matter of wonder and disbelief to most.  Magic seemed to happen before their eyes as these men created images that would take hours for an artist to draw, in a matter of minutes.

Talbot's - Trafalgar Square, 1843

Talbot's - The Ladder, 1844

Talbot's images were very different to Daguerre's unique images of the time.

Portrait by Daguerre

Portrait of a Boxer by Daguerre

These were known as Daguerreotypes, and are still used today by some artists.  Simply because of the individuality of the image created and the process it takes to produce them.

Perhaps some of the most famous, modern Daguerreotypes today are the ones created by artist Chuck Close.  In 2003 Close captured world famous fashion icon and model, Kate Moss using the Daguerreotype format.

Daguerreotype Kate Moss, By Chuck Close 2003

Daguerreotype Kate Moss, By Chuck Close 2003

Self Portrait from the artist - Chuck Close

There are still many types of film out there today, even though it seems at time we live in an age where digital has taken over.

120mm Film, known also as Medium Format - was a common size used during the 20th Century

Large Format film - an expensive hobby these days!

I'll talk more about film photography, societies and enthusiasts that still use the format in a later article.
Film photography is the true, original and best way to learn about photography and develop your skills.

Although more expensive to have as a hobby, even for a short time, it does pay off.

Hope you have enjoyed the lesson, next up....Film processing and how to do it!

Photography LESSON 1: The Camera Obscura

This is the first part of many lessons in photography to come.
I've been studying photography since 2008 and I know I still personally, have plenty to learn.  I also know that had I been taught certain things in a different order, my photography knowledge would have been pieced together a lot easier and certainly quicker than it was!  So with that, I am going to start from where I wish someone had started with me.
I hope this helps you understand the foundations of photography & why things happen for a reason.

LESSON 1:

THE CAMERA OBSCURA

First things first.  Don't be intimidated by the weird word.  Let me explain.....

Camera is Latin for "room"

Obscura is Latin for "dark"

Photography is thought to have been invented (using that term loosely) around 1893, although the concept of it has been around much longer - This was, and still is, known as the Camera Obscura.

We all know photography as capturing a scene.  Making an image on paper of what we see in front of us.  A way of recording and capturing an event, people, places and things. 

Thus, photography is a method of creating images.  To create an image we need both light and darkness.  Without this, photography would be nonexistent.

So what is the Camera Obscura and what does it have to do with my digital SLR or camera on my phone?  Have a look at this diagram.....

An early sketch to show the technique - 1544

  

All of what we see is down to light and how it travels.  Vision is a rather detailed process to explain, and I'm no scientist, but I'll attempt to break it down and relate it to photography terms.

Take a look at your eye, look at the pupil in the center of it.  This is what lets light in.  Your pupil becomes bigger in the dark because it needs to let more light in. On a sunny day, your pupil will be smaller as you don't need as much light to see.  The same method is applied to the camera obscura to create an image.

The candle labeled A on this diagram is what you see in front of you.  Such as this screen as you read!  Image B is what is received to your retina at the back of your eyeball, and yes, it is upside down.  Your brain then converts the image to the correct way up.  

It is upside down because of the way light travels. 

When light travels, it travels in a straight line.  Therefore, when rays of light are reflected from a bright source and passed through a small hole, it cannot scatter.  It must cross in a straight line and it then becomes an upside down image.

So here you go, the Camera Obscura.....

Imagine a completely dark room, with no light leaking in.  Windows covered in black material, the bottom of doors sealed with tape.  A small hole can then be cut in the black material to let light flood into the dark room.  The scene outside will then appear, as if by magic, upside down, on the opposite wall.
Have a look at this wonderful giant, camera obscura image created in a room using nothing but natural light and a tiny hole.

An image created in a room, Central Park, NYC - By Abelardo Morell

It truly is simple to create with unbelievable results.

This is how we came about creating, natural, raw images.  Nothing used except light and darkness.

Another camera obscura image created by Abelardo Morell - The Eiffel Tower, Paris 1999

Here is the famous light bulb set-up of a camera obscura.  Created in 1991 by Morell to show how the diagrams we have seen can be recreated on a small scale.

Light Bulb, 1991

It really is that simple.

At great artist to check out is Abelardo Morell (who is responsible for most of these images)
 - Born in 1948, Havana, Cuba.  Studying art from 1977, Morell became a Honorary Doctor of Fine Arts in 1997.  His photography work is definitely not one to be missed if you are interested in seeing more of these fantastic images.

Abelardo Morell's Official Website

The Neighborhood - by Morell

I hope this little insight on how light works and travels has helped you understand the first part of how your images are created.
Portable camera obscuras were created and used by artists, who to capture their image, traced around the projection, off the wall and onto paper. 

A large camera obscura used to create portraits

An artist uses the method to trace his image onto paper

A diagram of the camera above - a mirror is used to project the image onto the working surface

It wasn't until the late 1800's did the idea of capturing these images quickly onto a surface in some sort of permanent fashion come about.  This was through the development of chemicals and their reactions to one another.

I'll talk more about chemicals, film and capturing an image on the next lesson.

Until then, keep an eye out for a step-by-step tutorial on how to turn a room into a camera obscura!
Check out a few of the guys from National Geographic giving it a try.....
National Geographic try out the Camera Obscura