Depth of field is one of the most important aspects of photography you can learn. Use depth of field well in your photography and you can gain immense control over the look and impact of your photos. Unfortunately, depth of field also seems to be one of the toughest aspects for beginners to learn and master. Continue reading »
Tags: Depth of Field
subject is reproduced in a photograph can be very different from how it looked to you as you took the picture. When you cast your eye over a scene, everything in it seems more or less equally sharp, but sometimes in the finished shot only part of the subject appears acceptably sharp.
This zone of sharpness is called the depth-of-field, and it extends in front of and behind the point that you actually focused on. The size of the zone is determined by three key factors – the aperture of the lens, the focal length of the lens used, and the distance you are from the subject. Varying these three elements allows you almost complete control over the depth-of-field in a picture.
When most of the picture is sharp, we say there’s lots of depth-of-field. When only part is sharp, we say depth-of-field is limited. As we’ll see later, whether you go for extensive or limited depth-of-field depends upon the subject matter and how you want to depict it
Three main factors that can be used to control depth-of-field
1 The aperture.
There’s a simple, direct relationship between aperture and depth-of-field – the smaller the aperture, the more extensive the depth-of-field.
So if you want to keep as much as possible sharp, you should set as small an aperture as possible – preferably f/16, or even f/22 if your lens offers it.
Depending on lighting conditions and your film stock, you may need to use a tripod or some other form of support at such small apertures, as the resulting long shutter speeds create a risk of camera-shake.
If, however, you want to concentrate attention on just one part of the scene, and throw the rest out-of-focus, you should select a large aperture. Exactly how large this can be depends on the maximum aperture of the lens you’re using. On a 50mm standard lens it will be f/1.7, f/1.8 or f/2, but on a standard zoom it will typically be f/3.5 or f/4.5.
For general picture-taking, when you want most of the picture to be in focus, you might want to set a middling aperture of around f/8 to f/11.
This is what a program exposure mode sets when left to its own devices Whenever possible you should take control of aperture selection and use either an aperture-priority or manual mode.
Four common techniques using depth-of-field
Use these four common approaches when planning a shot to ensure depth-of-field works for you
1 Everything sharp.
With subjects such as landscapes, groups, interiors and travel you’ll usually want to keep everything sharp. Using a wide-angle lens set to a small aperture will give you extensive depth-of-field, perhaps from around one meter through to infinity. But there will be times when foreground interest is closer than that. Here you need to resort to a neat little technique called hyperfocal focusing that allows you to increase the depth-of-field.
As a rule-of-thumb, there’s twice more depth-of-field behind the subject than in front of it. So if you photograph a distant subject such as a landscape and focus on infinity you waste lots of depth-of-field. By focusing a little closer, you’ll extend the depth-of-field at the front so it comes nearer to the camera, while still making sure that infinity falls within the depth-of-field behind the actual point of focus.
You can guess the hyperfocal focusing distance, but life is much easier if your lens is marked with a depth-of-field scale. This used to be regarded as an essential feature, but with the development of wide-ranging zooms many manufacturers now omit one. If you do have such a scale, simply line up the infinity mark against the mark for the aperture you’ve set and, although the image in the viewfinder will look out-of-focus, the finished image will be sharp from front to back.
2 Main subject sharp with background completely out-of-focus.
There are some subjects where you want the main subject to stand out strongly from an out-of-focus background. Portraiture, where the emphasis is on the person, rather than the location, is probably the most popular area. What you need here is a use a telephoto lens at its widest aperture. It’s also worth moving the subject as far away as possible from the background – in cramped studio situations this is often impossible but outside against a wall or foliage it’s usually easier. Take care, though, that you focus accurately, as the limited depth-of-field will be unforgiving of any focusing errors. For portraits focus on the eye for the best results.
3Main subject sharp, with background out-of-focus but still recognisable.
Sometimes throwing the background completely out-of-focus is going too far. You want to show the subject in its natural environment, but with the background toned down to it doesn’t compete for attention. A person on the beach, for instance, an animal in the zoo, or a flower in a garden. Here a standard to short telephoto lens, somewhere from 50mm to 135mm, is ideal – especially if it’s coupled with a middle range aperture of around f/8.
4 Zone of sharpness deliberately limited.
Occasionally you may want to limit the depth-of-field to a very specific zone. Maybe in a portrait you want just the eyes in focus, and not even the ears or the tip of the nose. Here, once again, a depth-of-field scale on the lens helps, or, failing that a depth-of-field preview facility on the camera, This will give a visual indication of what will and won’t be in focus by manually stopping down the lens.
Summary
Overall, the practical use of depth-of-field can be summed up as follows:
To maximise depth-of-field and have as much sharp as possible use a wide-angle lens, set a small aperture and stand back from your subject
To minimise depth-of-field with only a small zone of the scene sharp use a telephoto lens, set a large aperture, and get closer to your subject.
27/08/2008 http://8x10cameras.com
Tags: Depth of Field
Muna wa Wanjiru asked:
Depth of field in photography can sometimes be a difficult and tricky thing for quite a lot of people to get their heads around. I know this for a fact since I was one of these people. And just to prove that Im not making this all up, Ill have you know that a number of my photography friends also admitted to this fact! The problem doesnt come in the beginning, but more towards the middle when youre mired knee deep in the explanation and you realize that what you thought you understood wasnt really what you should have understood.
Luckily for me though I now understand what depth of field in photography is, and can make things work properly so I can take a good photograph. To put it simply though and to start you out in your explanation, lets take a garden scene with a solitary rose right in the middle of it. You want to take a picture of the rose, but youre not sure how you want it to look so you start fiddling around with your camera and take a variety of different shots. In the first shot, you make it so that the rose and everything around it the garden and its surroundings are very sharp. Everything in this picture is sharp and clear.
Then you take another shot, but this time you place more emphasis on the rose, and put everything else slightly out of focus. You can still see various different forms from the background and you might be able to recognize them for what they are, but theyre not so well defined as earlier. Foreground elements though, are still very much recognizable. Then you go the next step and take another photograph. This time the rose is more prominent and eye catching, while both the foreground and the background arent as much, and most of it is blurred and blended in together.
The next shot that you take, you focus solely on the rose to the exclusion of everything else, and make both the foreground and the background completely unrecognizable as anything other than a convenient anonymous backdrop for you main focal point, the rose. Now, although that was a demonstration of what depth of field in photography can look like in a picture, it probably didnt explain very well exactly what it is.
You might have guessed, but for those of you who are wondering what on earth Im talking about, just like I used to wonder on earth, depth of field in photography was all about, here it is in nice simple sentences. depth of field in photography, very simply stated, is how much of foreground and background you put into your photograph.
If you take any photographic scene, the sharpness in front of, and behind your subject is what you would call depth of field in photography. If your subject is the main attraction with an out of focus front and back, you would have a shallow depth of field in photography, and if you have the whole scene in sharp focus, both front and back, you would have a wide depth of field in photography.
Its not exactly confusing just yet is it? It might not be exactly clear either, but then again, just reading this article isnt really going to solve all of your camera problems. You need to get out there with your camera and try different settings for you to be able to fully grasp and appreciate what depth of field in photography is.
That said, there are a few things that come into consideration when youre looking into depth of field in photography and those go along the lines of, image magnification, lens aperture setting and the focal length of your lens.
Tags: Depth of Field