Depth of field for beginners, really?

[rambler4466]

Depth of Field is the term. Depth of Focus probably meant to refer to hyperfocal distance, so forget about that for now. The link given by russellsnr is an excellent explanation of DOF.

Try This at home: Find something among your household goods like a colorful bottle of shampoo, or a can of soup.
Set it on a long table. About 2' behind it, prop up a book with a large printed title on it. Put your camera on a tripod or set it up on some books so it will be stable as you shoot. Set your lens to a focal setting of 60mm or 70mm. Then get the object you have chosen in clear focus (the camera will be about 5' in front of it).

Now without moving anything take a series of photos at different apertures. Start at f/22, then f/16, f/11, f/8, f/5.6, and f/4.
Get the images onto your computer screen. Take note of the book title. At f/22 you should be able to read it very clearly.
A lot is in focus so the Depth of field is DEEP. At f/4 the shampoo or soup can should be in focus, but not the book title. Not much is in focus so you have a SHALLOW depth of field.

Try this, too, to get an idea about lenses. Look at the shampoo bottle through a toilet paper tube. Notice how much is included around the edges of the circle. Now from the same distance, look at the same object through a longer tube like a paper towel tube. Notice how much less is seen around the edges that what was there when you looked through the shorter tube. So, as you zoom in on a subject with your camera the same will happen to the edges. Move in even closer and you will see more of a change. (I like taking close-up photos of flowers standing only a few feet away, but using a zoom lens.)

Do not worry about circle of confusion. It changes with every camera. Learn about hyperfocal distance next and you will find that calculators can factor in the circle of confusion. You will learn that DOF is not just important in close-up photography, but in landscapes where the distant subjects are at infinity. You will learn to focus at the hyperfocal distance to get subjects both close and far distant in focus.

I would recommend for you, since you are interested in details, the latest edition of Complete Digital Photography by Ben Long.

[William W]

Depth of FOCUS does NOT refer to nor does it have anything to do with the HYPERFOCAL DISTANCE.

In the video, the instructor corrected the person asking the question, because the person asking the question asked about "Depth of Focus" and what the question was actually about, was "Depth of Field".

These two terms are often used to mean the same thing: this incorrect so to do, as the terms have very specific and different meanings.

Hyperfocal Distance is related to Depth of FIELD.


WW

[rambler4466]

Be sure to look at the Depth of Field explanation found in the tutorial section at this website!

Wikipedia:
"While the phrase depth of focus was historically used, and is sometimes still used, to mean depth of field, in modern times it is more often reserved for the image-side depth."

Holy moly, I am being surrounded by another circle of confusion.

[William W]

Wikipedia:
"While the phrase depth of focus was historically used, and is sometimes still used, to mean depth of field, in modern times it is more often reserved for the image-side depth."

Aside:

That quote from wikipedia has been the leading sentence to that entry for quite a while.

Please note that the quote it is NOT referenced nor is it supported by any first source document in the footnotes.

I have yet to find any substantive evidence that there is any truth in that quote.

Certainly the Ilford Manual of Photography (1890) predates by decades the earliest reference in the wikepedia article which is: Introduction to Photographic Principles ( Larmore, Lewis. 1965).

Two editions of the Ilford Manual, Edition 4 (circa 1930) and Edition 5 (1958) both clearly separate the meaning of the two terms: "Depth of Field" and "Depth of Focus"


WW

[rtbaum]

I hope that this web site may help
http://www.cs.mtu.edu/~shene/DigiCam...-of-field.html
P.S. As I post this, CBS evening news is playing a story about Kodak's history. Must be Kharma

[rpcrowe]

Could I give a rather simplistic definition of circle of confusion but, as Colin mentions, all that you need to know...

The smaller the original image format captured by the camera (full frame > 1.6x crop > 4/3 > various P&S size formats); the sharper that the capture must be in order to produce the final larger image that is acceptable sharp. Circle of Confusion is a numerical representation of the sharpness required in order to produce acceptable sharpness in the image. This is used in various formulas to determine the depth of field (DOF = the distance between the nearest and furthest points of acceptable focus).

As Colin mentioned, we don't need to know the formula in which DOF is calculated. There are numerous charts and websites (such as DOF Master below) in which you can enter the parameters controlling the DOF: f/stop, focal length, distance focused on and image size (you don't need to know the circle of confusion, you just need to enter the camera model ) and the chart will provide the nearest and furthest points of acceptable focus.

http://www.dofmaster.com/dofjs.html

As an analogy, you don't really need to know the principles of the internal combustion engine in order to drive your car. You don't even need to know WHY one car will get better gasoline economy than another, simply that it does!

[anita]

Hello,

Sorry for the "missing". I've tried to find an explanation, let's say that i've found some movies, one of it http://www.indymogul.com/post/9097/v...field-tutorial.

Let's say for the moment i'am ok with DOF.