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What Is Depth of Field (DOF)?
Depth of field (DOF) is the distance wherein objects are in focus and the background are out of focus.
This is the pragmatic explanation.
To be technically correct, DOF is the zone of acceptable sharpness, the area in front of, and behind, a focused subject that appears in focus.
Technically, only the subject in focus -- and all other objects at the same distance -- are in focus; everything else in front and behind are out of focus. How much out of focus depends on a term called the "Circle of Confusion (COF, or COC)."
Imagine we are photographing three (3) dots. They are the tiniest dots the human eye can clearly make out, and of course, we are assuming perfect 20-20 vision and ideal light condition.
So, here we have these 3 dots, arranged one behind the other (with the closest dot to the right of the middle dot, and the farthest dot to the left of the middle dot, so a camera can take a picture of all 3 dots).
Now, we focus our lens on the middle dot, which comes out in perfect focus. The two other dots also appear in focus, but peering closely at the resultant photograph, we notice, however, that the dot in front of and behind the middle dot appears as circles instead of perfect dots. I.e., technically, they are out of focus, but to our naked eyes (at a "normal" distance), they "appear" in focus.
It is this circle that we call the "Circle of Confusion." So the COF is the diameter of a dot such that when we view it with the naked eye, it appears in focus. If this circle gets past this diameter, our eyes tell us it's out of focus.
What Affects DOF
What we really want to know as photographers is what affects DOF so we can control DOF in our pictures. For a long, long time, photographers have gone with the following three criteria:
While the first two are technically correct, the third one has raised somewhat of a storm of controversy among certain circles. Why exactly, we will make clear later. Let's look at each of the three criteria in more detail.
Lens Aperture
The aperture is simply the size of the opening that allows light to go through the lens. It is expressed in f/stops (also referred to as f/value or aperture value), and a typical aperture range is f/2.8 - f/8, giving the range from maximum (large at f/2.8) to minimum (small at f/8) aperture.
A small f/value (e.g. f/2.8) indicates a large aperture.
A large f/value (e.g. f/8) indicates a small aperture.
So, f/2.8 is a larger aperture than f/8.
Generally, a large aperture gives a shallow DOF, and a small aperture gives great DOF.
Putting Aperture into practice:
Saturday morning while browsing again into the internet and visit online news at Gulfnews and find out that what I feel last thursday night is true and correct. There was an earthquake in Dubai on that night but the epicenter was in Ras Al Khaimah northern part of the United arab Emirates.
Now what? if there is an earthquake in United Arab Emirates... As all we know that UAE specially Dubai are constracting a lot of building and as far I know all this building they are constructed/constructing are not earthquake resistance since thay are saying that there are no earthquake here in Dubai...
When it comes to portrait digital photography and photography poses or shall we say, posing for portrait photography, there are many differentials and some of them aren’t obvious. It’s true that while your active organising portrait photography posing with your subject that many new posing ideas will come to mind but you will still need to know the rudimentary basics. Any studio posing will require posing techniques which will vary from posing the female model, baby portrait poses, family portrait poses, wedding photography poses, and even senior portrait poses. They all vary in their portrait pose requirements.
Photography poses are very strenuous on the model or subject as well and there is usually a photography posing guide or a model posing guide that can help your understanding with these areas. Fatigue and restlessness must be considered at long shoots for instance while models are posing for portraits. I recently saw an article that was a guide to posing the female body; however it was too focussed on the one aspect and left little room for photography posing of other types.
The rest of this article offers some posing tips for a photography pose in general and is compiled to stimulate your interest in portrait posing because once you have the basics, your portrait posing skills will compound with each new sitting. To photograph a pose and make it look natural and interesting is what your goal should be with posing. Remember not to treat portrait poses lightly and you will get much better at this skill in a short space of time.
Portrait photography is also a photography business that can be initiated from home. Often only requiring modest photography equipment , you’ll only need several pieces of cloth (backdrop), a camera, some good lenses, two or maybe three lights and let’s not forget the tripod. In addition to the equipment being modest by any ones standards, it is all reasonably lightweight and easy to handle should you need to work outdoors.
The most important rule to remember is that it is a portrait, not necessarily of just the head, but the person, or group is the focal part of the picture, so it is important to take the photograph without any extraneous clutter. Because you will always be dealing with people with whom you have to maintain control, not as a tyrant, but you have to guide your subjects. Therefore a certain degree of self-confidence is necessary. If you are taking a formal portrait of a group of children it is necessary for you as the photographer to ensure that none of the children are making faces.
This brings us to posing. Many photographers underate this essential requirement because posing will make or break your portraiture. There is much value in learning to guide people through various poses. Posing has an ongoing education requirement depending on age, gender, culture, promotion, product, and emotion needed for each piece of art etc. It is such an important and extensive subject that I’ve provided you with this downloadable guide which I think you should take seriously - Make Camera Friendly Posing Happen!
When you have signed up a person for a photographic portrait take a few extra shots, and offer them as wallet or purse photographs at a smaller fee. You already have started the business, capitalise on it, few people can resist the feeling that they have got “something for nothing”. This may seem a waste of time; they can be important additives for your portfolio.
Portrait photography has undergone many changes of style since the introduction of the formal portrait. The modern emphasis is to bring out each individual’s personality. Top glamour models are paid enormous fees to express a distinctive personality, but to bring that aspect forward in your subject is as much about people skills as camera techniques. It is imperative to be able to create a rapport with your subject to bring out the expressions that display their personality. Anyone over the age of two can pose for the camera, with a vacuous expression, but the secret of saleable portrait photography is capturing more than the pose. To be a really good portrait photographer you have to be able to connect with people, if you have not got these skills, then it is better that you concentrate on some other type of photography-perhaps underwater photography if you want to be more active and adventurous
If you want to flatter your subject, you’ll probably want to minimize their nose. Stand about twelve feet from your subject, so that their nose isn’t significantly closer to you than the rest of the face. However, at such a large distance from the camera, if you want to fill the frame with just your subject’s face, then you need a high magnification lens. Typical “portrait” lenses are therefore between 90 and 135 millimeters long when you are using a 35mm camera.
Whilst a lot of portrait photography is completed inside a studio, the prospect of natural light can be very flattering. This can be achieved inside by positioning your subject in front of a window. Environmental portraiture presents different challenges. These portraits are best enlarged, otherwise the subject’s face gets lost in the background. Slow film and the use of a tripod; help to keep your images sharp. There are a number of professional photographers who argue that a portrait is not shown to it’s best advantage when it is clinically sharp and they use a filter, but with modern digital cameras, you can make an adjustment in Photoshop at a later time. However if you are using a digital camera you will achieve the best results with a camera with a true single lens reflex.
Natural light or umbrella lighting can achieve soft lighting; both of these reduce shadows and show the face in a “better more attractive light”. However there is another type of portrait photography, which is high impact photography. This is a very dramatic type of portrait photography, which uses very strong light with a high contrast of tonal color. This technique is more effective indoors, as it is achieved by controlling light, and there is too much light to control out of doors. Position your subject at different angles to the light, from one side, or from underneath. This lengthens the shadows, rather than muting them, and gives a distinctly dramatic effect. You can achieve this in varying degrees, but if the light source is placed at 90 degrees to the face, it will throw the whole of the opposite side of the face in shadow. If you are using a digital camera you can also manipulate the contrast later to achieve a more dramatic effect.