|
Home / Hobbies / Photography
Aperture and Depth of Field for Photographers
By:Jennifer Clarkson
First, let’s review the three things that directly influence how all photos are captured on both film and digital cameras:
1) Aperture: the lens opening
2) Shutter Speed: the speed of opening and closing the shutter, which determines how long the subject matter stays on the film that comes through the given aperture
3) The speed of the film (a.k.a. ISO setting), which directly influences what choices of aperture and shutter speeds you can use
ISO Setting
Before your camera can detect aperture and shutter speed for a particular subject, it must be told how many worker bees are loaded into the camera (i.e. the film and its corresponding ISO). The more worker bees there are, the less time they need to capture the same amount of light, so the ISO setting directly impacts the aperture and shutter speed settings.
These days, ISO on film cameras is detected by a bar code on the film’s cassette, which the camera reads and then tells the light meter. On digital cameras, you can set the ISO to a particular rating by selecting it in the menu, or leave it on the automatic setting so that the camera decides which ISO speed to use. Once your camera knows how many worker bees it has, it will be able to detect which aperture and shutter speeds are ideal for various conditions.
Aperture
Aperture controls the volume of light that passes through the lens and onto the film. The volume of light is determined by the size of the lens opening (the aperture): big, medium, or small openings. Aperture works in conjunction with Shutter Speed to correctly expose an image. Depending on the lighting conditions (night vs overcast vs sunny), a given aperture will require a different partner shutter speed.
Most cameras recommend these settings automatically for you, assuming you want everything in the photo to be in focus. You can usually opt to set the aperture and have the camera pick an appropriate shutter speed (called aperture-priority), or vice versa (called shutter speed-priority). If ever you want to change the depth of field (i.e. what’s in focus), the aperture-priority setting will come in handy, if not full manual where you set both aperture and shutter speed.
Depth of Field
The term ‘Depth of field’ simply refers to a picture’s overall sharpness. It is the direct result of the aperture setting on your camera. By setting the aperture (a.k.a f-stop) to a small number – e.g. f/2.8 – you are setting the lens opening to be large. Such a “wide-open” aperture limits the plane or field of focus to be very narrow: this is called a small or narrow depth of field. For example, if you’re photographing a long line of fuzzy ducks extending into the distance, and you only want one duck in the middle to be in focus, then you would open up your aperture by setting it to a small number, such as f/2.8. Once you’ve chosen this setting, your camera will help you figure out the appropriate shutter speed to provide a good overall exposure.
By setting the aperture to a large number – e.g. f/16, f/22 or even f/32 – you are setting the lens opening to be very small: this is called a large depth of field. This small aperture allows the camera to focus clearly on things both close and far in the same shot. Continuing on with our fuzzy duck example, using a small aperture will allow you to capture the entire row of ducks in perfect focus. The near duck will be just as sharp as the far duck, as will all the ducks in the middle.
Try it out! Once you’ve focused on a subject, you will notice that there are areas beyond and/or in front of what you focused on that are not sharp. Assuming you want everything sharp, the laws of depth of field say to use a small aperture of f/16, f/22, or f/32. If you instead want a narrow field of sharpness in your image, the laws of depth of field say to use a wide-open aperture of f/2.8 or f/3.5.
In a nutshell, those big aperture numbers - f/16, f/22, f/32 – render the greatest depth of field or area of overall sharpness and those smaller aperture numbers – f/2.8, f/4, f/5.6 – render a minimal area of sharpness beyond or in front of what you have chosen to focus on. Again, depending on lighting conditions, different shutter speeds will be required to expose the image correctly.
Caveat for digital photographers:
These depth of field rules and example f-stops were created for those using 35mm format cameras, and you will find reference to them all over books and the internet. Digital cameras are typically closer to 38mm format, and will thus have better results narrowing their aperture (so as to get everything in focus). The claim to fame of digital cameras is to have excellent focus from near to far - infinity and beyond, but in doing so have limited ability to capture narrow focus. For example, f/2.8 on a typical digital camera will not be a large enough aperture to narrow your depth of field sufficiently to only get one fuzzy duck in focus. DSLR owners can simply purchase a macro lens to do this, but digital point & shoot owners may not have the capability to narrow their depth of field noticeably. Best to stick to landscape shots!
Digg
del.icio.us
Blink
Stumble
Spurl
Reddit
Netscape
Furl
Article keywords: photography, photographer, aperture, depth of field, digital, digital photography, film, camera, ISO, shutter speed, DOP
Article Source: http://www.articles2k.com
Jennifer Clarkson is a Canadian photographer living in Ottawa. For more photography articles, and to see her photos, please visit www.jclarksonphotography.com.
|
|
| Top Photography Articles |
- 1). How to Select a Local Model Agency Without Getting Burned By : Bob Pardue
If you are an aspiring model, especially a beginner, you'll want to read this article before making any
contacts to model agencies. It's tough enough pursuing a modeling career when you are prepared but almost
impossible if you aren't!
The old cliche that says, "I'll just go down to the corner of Main or to the mall and get discovered." is totally
bogus! Believe it or not you're going to have to do some honest work to create a need for your modeling
services.
|
- 2). Fashion Models - Start Your Engines By : Bob Pardue
How to Promote Yourself as a Freelance Model
If you would rather promote yourself ...
Some models would rather promote themselves instead of listing through an agency. Nothing wrong with this but it does require more work on your part.
If your are signed with an agency, they promote the business, they talk to the clients in your behalf, they set up the shooting dates, they take the heat if you don't make it to the session, etc.
|
|
|
- 4). Underwater Cameras:Discover A Whole New World Underwater By : Albreht Moy
It is a known fact that over seventy-five percent of our world is covered in water, this world has just as many interesting things to take pictures of and is always changing with every ripple and wave. Underwater cameras are a great way to capture these scenes that are ever changing. Underwater cameras are great for deep-sea divers and the snorkeling community alike.
|
- 5). Get The Most Out Of Your Camera. (Part 1). By : TJ Tierney
Did you ever see an image where only a small part of it is sharp? Using the aperture ring correctly can maximise the artistic look of your image.
Not only does it determine the depth-of-field, it also has the power to direct the human eye.
The human eye is instinctively drawn towards noticeable points of an image. These are usually the sharpest and most important parts of an image.
|
- 6). How do Underwater Cameras Work? By : Nicola Kennedy
Underwater Cameras are cameras that are specially designed for underwater use or in circumstances that requires protection to prevent any water and pressure damage. There are many types of underwater cameras, depending on your budget and uses.
There are underwater cameras that are simply disposed of after use. These are the cheapest type of underwater camera available in the market.
|
- 7). Photography as a Fun and Interesting Hobby By : James Hunt
Photography is a fun hobby that interests many different people across a broad range of ages. Enthusiasts of all types have found a creative recreational outlet in the hobby of photography and with the advances in technology that have occurred in recent years ...
|
- 8). Filters For Landscape Photography. By : TJ Tierney
Filters are used in photography to bring back an image to the way our eyes have perceived the original scene. Some times it’s not possible for our cameras to record an exact scene - so we have to rely on the manufacturers of camera products.
Filters also help us to create mood in our images and bring out the best in a scene. A small selection of filters is well worth packing when heading off for a trip.
|
- 9). Use multi flash card readers to overcome data storage format incompatibilities. By : Ron Donnelly
As advanced consumer electronics like digital cameras, PDAs, multimedia mobile phones, and similar devices become increasingly affordable to the everyday user, we find ourselves having to keep track of more and more types of technology, which makes keeping all of our devices compatible with each other increasingly difficult. The technological marvels.
|
- 10). How To Take Better Kitten Pictures By : achiever
I compare my kitten with my kids and the love for my kids is equal to the love I have for my kitten, and that is why I make time to take my kitten pictures as my kittens grown into a lovely adult cat.
When anyone visits my home, they notice how well groomed my kitten is, and how well treated, and they also notice the collection of pictures I have of my kitten, I place my kitten pictures all over my home.
|
| New Photography Articles |
- 1). Digital Photography: Passion and Hobby Becomes Art By : John Darby
This article has put together a few tips to help you get convinced on the advantages of going digi and we have summarized the things that need your first priority or utmost attention toward the learning curve as soon as you begin to implement it in your work flow.
|
|
|
- 3). Digital Photography: In Focus By : John Darby
Learn how to take, edit and print your photos the right way using your digi cam through this article. This article discusses the tools and the features of a digital camera as well as the necessary tools in printing your digital photographs thereby eliminating the strange feeling that you will feel upon handling a digital cam.
|
|
|
- 5). How to Select a Local Model Agency Without Getting Burned By : Bob Pardue
If you are an aspiring model, especially a beginner, you'll want to read this article before making any
contacts to model agencies. It's tough enough pursuing a modeling career when you are prepared but almost
impossible if you aren't!
The old cliche that says, "I'll just go down to the corner of Main or to the mall and get discovered." is totally
bogus! Believe it or not you're going to have to do some honest work to create a need for your modeling
services.
|
- 6). SLR Film Photography Special Effects (Part 2) - Impressionist Effect By : Photo Views
This is a second article addressing SLR film photography Special Effects techniques that can be accomplished “through the lens”, being immediately immortalized on the film and ultimately the negative.
It requires no special instructions to the developing agent, whether your local photography shop or mail in developing service. Your prints will be developed with perfect exposure.
|
- 7). Panasonic Combination Digital Cameras By : Mike Reed
All About Combination Digital Cameras
Digital cameras are starting to become less attractive than all in one digital cameras which can often do many things other than just snapping photos such as record video, and play music. This certainly comes true in the Panasonic digital camera models. In an effort to show this wonderful technology, this article will look at one of the combination digital cameras.
|
- 8). Photography Q&A: The Basics Of Developing Photographs By : Travis Partrige
* Can I develop my own photographs?
Yes, you can. By having your own darkroom, it is possible that you can develop your own photos. You first need to set up your own darkroom and buy darkroom equipment.
* What equipment and supplies do I need in a darkroom?
A darkroom requires many kinds of equipment to get you started in developing your photos. It is expensive, so you should prepare a sufficient amount of money to get into this hobby.
|
- 9). How to be Prepared for Your Fashion Model Shoot By : Bob Pardue
The fashion model session - What to pack in your model case
OK, you're off to a model photo shoot. But, did you remember to pack your bag? Did you put everything you need in it? I hope this article will be helpful to you and start you on the right foot in making sure your model bag is complete.
What do you bring?
What you bring to your model photo session will depend upon whether this is your first shoot for a portfolio or a paying job.
|
- 10). Getting Photo Printing Help By : Matthew Noel
Photo printing help is commonly needed. With more individuals purchasing digital cameras, there is a wide need for help in printing off their pictures. While most standard computers with a decent printer can handle a good quality photo, others are looking for exceptional quality photos. The good news is that there is a wealth of help to be found for those who need it.
|
|
|
