Once you grasp the basic principles of focusing your photographs will take on a whole new depth.
Words Steve Bavister, Images Peter Bargh
| |The way a 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.
| | Excuse the state of this old Nikon lens, but it helps to show what we're talking about and by blurring the surrounding area it's easy to show the scale and depth of field. Look at the picture with the lens set to f/22. At this setting the lens will ensure everything from infinity (the symbol that looks like a figure eight on its side) to two feet is sharp. With the lens set to f/8 the zone of sharpness is reduced to infinity to just over five feet.
2 The focal length of the lens.
Attach a wide-angle lens and you'll benefit from extensive depth-of-field, which makes it easy to keep everything in focus. The wider the angle-of-view, the greater the depth-of-field. Choose a telephoto lens and the depth-of-field is immediately more limited. The longer the focal length, the more restricted the zone of sharpness is.
| | Here I've illustrated the affect of using a different focal length. A Nikon 28mm wide angle at f/22 would as we've seen give a sharp result from two feet to infinity; a 55mm Micro Nikkor from seven feet to infinity and a 105mm Nikkor from about 28 feet to infinity .
|3 The Camera-to-Subject Distance |
For various technical reasons, the closer you get to the subject the more limited the depth becomes. In fact, when shooting close-up subjects it can extend to just a few millimeters in front of and behind the subject.
So that's the theory, but what does it all mean in practical picture-taking terms?
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.
| | A small aperture was used to ensure the foreground stones were as sharp as the ones in the distance.
|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. |
| | If you focus on infinity all the potential sharpness beyond infinity is wasted and the closest zone of focus, on this 28mm example, is about four feet.
Adjust the lens so that the infinity setting is on the marking of the aperture you have selected to extend the zone of sharpness to about two feet.
|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.
| | Plants often have distracting backgrounds so focusing on the flower head and throwing the background out is a common technique used to isolate the subject.
|3 Main 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.
| | In this shot of hay the background has been deliberately pushed out of focus but not by too much so that it is still obvious what it is.
|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.
| | A technique used by many flower photographers is to really limit the depth of field. Here just the stamen is sharp making the foreground and background petal really soft.
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.
By: DavidQuest 708 days ago
Thanks for your explanation of depth of field. I have a question.
I want to shoot with a narrow depth of field. So, I add a telephoto lens to my camera but now to get my subject in the viewfinder, I have to stand about 50 feet away. Can I add a wide angle lens in front of the telephoto lens so I don't have to stand so far away?
Thank you for your comments.
By: soneoutt 618 days ago
By: soneoutt 617 days ago
Year 2013 has been quite eventful. SRSG also witnessed events and evolved in terms of business verticals, technologies, people and processes.
Apple product dealers delhi
Apple authorized service center Delhi
ipad dealers in Bhubaneswar
Mac pro dealers in Mumbai
Apple service center Mumbai
Jika anda merasa bingung dimana mencari referensi harga mesin terbaru dan terupdate maka anda dapat langsung mengunjungi situs kami, langsung saja Lihat Artikel
yang mana telah ada informasi super lengkap mengenai harga mesin terkini baik itu mesin jahit dan juga mesin fotocopy. Anda seorang pengangguran? Jika iya maka anda perlu memulai usaha sendiri daa menjadi seorang wirausaha yang sukses, jika anda bingung memulainya silahkan baca artikel
ini yang mana kami telah membagikan referensi peluang usaha baik sampingan, modal kecil ataupun tanpa modal. Jika anda seorang ibu rumah tangga yang ingin membuat masakan lezat namun terhalang karena tidak bisa membuatnya maka anda dapat membaca resep cara membuat masakan lezat pada situs kami di http://resepmembuat99.blogspot.com
atau anda dapat langsung membaca salah satu artikel kami yakni Resep Cara Membuat Kue Blueberry Rich Cake Ala Blueband
yang mana akan di berikan informasi seputar kue blueberry rich yang super lezat dan nikmat. Selain itu anda juga bisa menyimak Resep Cara Membuat Martabak Mie Enak dan Gurih
yang dapat anda pratekkan bersama keluarga tercinta, atau melihat artikel Resep Cara Membuat Roti Bakar Kacang Pisang Ala Blueband
yang berisi info membuat roti bakar kacang yang enak, atau melihat artikel Resep Cara Membuat Kue Pandan Choco Cookies Yang Enak
yang berisi informasi membuat kue lebaran pandan choco, atau melihat artikel Resep Cara Membuat Nasi Goreng Blueband Super Lezat
yang mana berisi resep spesial sajian sarapan nasi goreng super enak, atau melihat artikel Resep Cara Membuat Roti Biskuit Susu, Sajian Sarapan Enak
yang mana berisi tips membuat roti biskuit susu yang enak, atau melihat artikel Resep Cara Membuat Kue Cheese Streusel Cookies Sajian Lebaran Lezat
yang mana anda akan di berikan cara membuat kue cheese yang lezat, atau melihat artikel Resep Cara Membuat Nasi Goreng Kampung Yang Lezat
yang berisi cara membuat nasi goreng kampung super lezat dan mudah membuatnya, atau melihat artikel Resep Cara Membuat Roti Kacang Tabur Apel ala Blueband
yang mana berisi membuat roti kacang tabur apel yang super lezat dan yang terakhir anda dapat membaca Resep Cara Membuat Kue Katberry Cheese Ala Blueband
yang mana semua informasi resep di atas dapat anda jadikan referensi membuat makanan lezat. Anda sebagai pemula dalam hal memasak dan anda bingung ingin belajar memasak dimana? Saat ini kami menyajikan kumpulan resep yang dapat anda baca sebagai referensi belajar yakni pada url kami di http://resep-kuliner99.blogspot.com
atau anda dapat membaca resep spesial kami yakni Resep Kue Blueberry Rich Cake Ala Blueband Yang Enak
yang cukup mudah membuatnya. Selain itu kami juga memiliki banyak kumpulan resep seperti Resep Martabak Mie Ala Blueband Super Lezat
yang lezat dan mudah membuatnya, atau anda dapat membaca artikel Resep Roti Bakar Kacang & Pisang Ala Blueband
yang mudah serta menyehatkan, atau anda dapat membaca artikel Resep Kue Pandan Choco Cookies Ala Blueband Enak
yang lezat dengan aroma pandan yang di padukan dengan cookies lezat, atau anda dapat membaca artikel Resep Nasi Goreng Blueband Lezat Menyehatkan
yang mudah membuatnya, atau anda dapat membaca artikel Resep Roti Biskuit Susu Ala Blueband Super Lezat
yang lezat dengan susu biskuit, atau anda dapat membaca artikel Resep Kue Cheese Streusel Cookies ala Blueband
yang enak dengan taburan keju, atau anda dapat membaca artikel Resep Nasi Goreng Kampung ala Blueband Yang Enak
yang lezat khas kampung yang sederhana, atau anda dapat membaca artikel Resep Roti Kacang Tabur Apel ala Blueband
yang lezat dengan taburan apel sangat cocok untuk sajian menyehatkan dan yang terakhir anda dapat menyimak Resep Kue Katberry Cheese Ala Blueband dengan Video Cara Membuatnya
yang enak dan lezat sangat mudah membuatnya, sangat cocok sebagai sajian lebaran menyehatkan.
betawi daerah ibu kota jakarta yang dapat anda buat dengan mudah sekali.Anda seorang yang tidak bisa memasak dan sekarang ingin belajar memasak, jika iya maka alangkah baiknya jika anda membaca kumpulan resep terlengkap dengan cara baca artikel atau anda dapat membaca salah satu resep spesial dari kami yakni cat forklift parts
Lately, either fitness and health freaks furthermore new this exercisers are actually choosing a different out of doors physical exercise software rather then toiling for any gymnasium. This will not be without owning reason if you enroll in Amazingly Fit and slim health workout besides lecturer all-around benefits; healthsegment.com
The park is aesthetically pleasing and Lincoln is a very nice college town with plenty of other things to do and see. A trip to Haymarket Park should be on the list of any college baseball fan. buy 1 million youtube views
I simply want to tell you that I am new to weblog and definitely liked this blog site. Very likely Iím going to bookmark your blog . You absolutely have wonderful stories. Cheers for sharing with us your blog. Fresno SEO Kings
The best answer to this question is to deploy a WIDS/WIPS solution, which will provide the most holistic protection from wireless threats in the enterprise. bluetooth headset reviews
I just thought it may be an idea to post incase anyone else was having problems researching butmore info
I am a little unsure if I am allowed to put names and addresses on here.
This is surely the best place one can get useful info about what he needs.here
kudoss to the real admin of this site...
Snowden also seems eerily resigned to the likely consequences of his actions a?? namely more helpful hints
that he may never see his home country again, and that government officials may come for him at any time.
Get your work done so you can enjoy the rest of your day. more helpful hints
Try Neuroflexyn as a brain stimulant. Focus.
You should comment on the competitionAmazon store keyword tracking
comparison of the blog. You can highlight it's mind boggling.
Safe Work Method Statement Template NSW
Thanks for taking the span to agitate about this, I sense strongly about it plus like lore better on this subject. If viable, would you intelligence updating your blog among extra info? It is exceedingly beneficial for me.
Want You review and buyers guide that provides an insider's look at the program and answers frequently asked questions about Jason Capital's unique and highly popular system for helping you meet, attract, and seduce hot women.loft conversions
Add your message
Please login here
or if you've
not registered, you can register here
. Registering is safe, quick and free