Shooting in Av mode (Aperture Priority)

If you have been useing your DSLR (Digital Single Lens reflex) camera in auto mode then here is a lesson for you.  

First an explanation about aperture and how it affects your final photograph.  

Inside your lens there is a diaphragm that controls the amount of light reaching the image sensor. The diaphragm functions much like the pupil of the eye – it controls the effective diameter of the lens opening. Reducing the aperture size increases the depth of field, which describes the extent to which subject matter lying closer than or farther from the actual plane of focus appears to be in focus. In general, the smaller the aperture (the larger the number), the greater the distance from the plane of focus the subject matter may be while still appearing in focus.  

Higher diameters (lower f numbers) alow more light to pass through but have a shallow depth of field, while smaller diameters (higher f numbers) allow less light through but more detail farther away from the point of focus will be sharp.

Your camera measures aperture in F Stops ( F/N.N ). The n.n represents the F Stop Number.  The lower the numbers are the the wider the diameter and higher numbers mean a tighter diameter. 

For example: 

You are taking a photo of a bird and there are some grass in front of the it that you want to blur out a little but still keep the bird sharp. What you want to do is use the lowest aperture possible that will keep the bird in the best focus.  

Exposure: 

For proper exposure of the image a precise amount of light striking the recording media is required .  At lower F Stops this light will accumulate faster than higher ones.  Here is where the shutter speed comes in.  

In aperture priority mode the camera will you chose how long to keep the shutter open.  You

can usually adjust the exposure either with a wheel (optimal) or with a set of up and down buttons.

Try focusing you camera on the bird and taking a shot.  Keep adjusting until you get the result you are looking for.  Yes maybe until it flies away, but keep practicing you will get the hang of it.

Three Secrets To Mastering Perfect Exposure

Memorize this short “mantra” in order to master photography – ISO, shutter speed, aperture. If you repeat this to yourself a few times you will be able to easily remember the three things that will always save, or ruin, an exposure. They don’t have to come specifically in that order, but nevertheless, these three things are what will determine your exposure.

Why are they so important?

When we talk about a photograph we usually speak of it in terms of subject matter, lighting, balance, etc. In reality, the three things that make that picture possible or effective were the ISO, shutter speed, and aperture. If you can master these three activities then you will be able to always create the kind of results you want, regardless of conditions.

Remarkably, even the most modern of digital cameras cannot always guarantee success. That includes top of the range digital cameras. If the camera allows the photographer to shoot entirely in manual mode, however, almost any sort of lighting conditions or photographic requirements can be tackled. Even better, if the camera has “semi-automatic” features such as aperture or shutter priority settings the photographer’s life just got even easier.

Don’t know about these settings?

Well, there are all kinds of descriptions, metaphors, and illustrations as to how these three factors interact to make a final image, but these tend to make very little sense unless you really understand the fundamentals of the three settings. It begins with ISO, which is the sensitivity of the camera’s sensor to the light entering through the lens. The ISO can be automatically adjusted to ever increasing levels of sensitivity, but this comes at a cost, and that is digital “noise” or graininess in the photograph. Instead of making the sensor do the work, the photographer should consider letting more light into the camera.

This can be done via the aperture of the lens or the speed of the shutter. Both choices also come with some valuable and steady compromise, and it is up to the photographer to select the right setting for their photographic intention. When they decide to allow more light in through the lens, by opening or closing the aperture they will instantly change the depth of field. This will make the background and foreground sharper or blurrier. When the photographer sets the aperture at a very low number, such as 2.8, they are actually flooding the camera with light. This shortens the depth of field and makes everything but the subject extremely blurry. Obviously a smaller or higher aperture setting will do the opposite, and this is usually what a landscape or cityscape photographer chooses.

If they decide to control light through shutter speed they will have to understand that slower shutters allow a lot more light into the camera, but this runs the risk of adding blur to the image too. Shutter speed also has a lot to do with controlling motion. When something is moving fast, you will be able to capture that motion as sharp and “frozen in mid air” or, alternatively, you may simply choose a “streaky blur” look to add more artistic value to your image.

A common problem photographers have is shooting fast motion in low light. There really is no “magic” answer to this. You need as much light as possible. Since there are only really three ways to enhance the lighting in your images, you really only have three options available to you; a slower shutter, a wide aperture or a higher ISO. Each have their advantages and disadvantages and it is up to you what you are prepared to gain and prepared to lose. You may want a frozen in mid air look of a fast motion subject and are prepared to have a little more noise in your image. Or you may choose a slightly blurrier look but a lot less noise.

If the photographer knows that they must have a specific aperture or shutter speed for the image, and the camera has priority modes, they can simply set the element that they want, and the camera will tackle the rest. The trick is learning exactly what is required!

If you like this article, please feel free to leave a comment below and bookmark it if you can spare a minute.

This article provided by Amy Renfrey (visit her website)

Taking Portrait Photos with Blurry Background and Understanding Depth of Field

We have all seen beautiful photos where the object is perfectly focused while the background is blurred. Such a photo can be very dramatic and might seem to be hard to shoot. In this article we will give you a few tips on how to easily take blurry background photos that will impress your friends and family. You will also better understand what Depth of Field is and how to control it.







Depth of field (also known as DOF for short) is the most important thing to understand before shooting a blurry background photo. Depth of field is defined as the range in which the photo is in focus. For example an infinite depth of field means that the photo will be in focus from a certain distance from the camera and up to infinity. When taking a blurry photo the goal is to set the depth of field just around the object. In this way the object is in focus while the background behind it is not.

How do you control the depth of field? After all there is no “depth of field” menu in the camera (wouldn’t that be nice…). Depth of field is an optical figure that is influenced by a few factors:

The distance of the object from the camera:

This is obvious to understand when taken to the extreme. Shooting an object 10 feet from the camera will result in a smaller depth of field than shooting an object 100 feet from the camera. Obviously shooting an object which for all practical purpose is infinite distance from the camera will result in the camera focused on infinity and the depth of field being infinite too...

The aperture:

The wider the aperture (f number decreases) the smaller the depth of field and vice versa: the narrower the aperture (f number increases) the greater the depth of field. Just remember that the depth of field changes along with the f number: when the f number increases and depth of field increases and vice versa. Unfortunately you can not just change the aperture as you wish. Changing the aperture results in a need to change the shutter speed (either manually or the camera can most likely do that for you automatically). The wider the aperture the more light that penetrates the lens and the faster the shutter speed needs to be so there is a limit to how wide you can set the aperture to.

The focal length of the lens:

The shorter the focal length the greater the depth of field and vice versa the longer the focal length the smaller the depth of field. For example if you use normal lenses at somewhere around 50mm your depth of field will be much greater than if you use zoom lenses at 200mm. With long focal length the depth of field can be extremely small. For that reason zoom lenses are a good choice in order to shoot a good blurry photo that is practically focused only on the object.

After understanding the theory it is best to go to the field an experiment. You will get a sense of how your photo will look like and how blurry the background will be after playing with different lenses, different apertures and different distances from your object. If you own zoom lenses start with taking photos of a relatively close object while using your zoom lenses. You will find out that it is extremely easy to get a blurry background photo using this method even without setting the aperture. Once you feel comfortable with that setup start changing the aperture and also change to your normal 18mm-55mm or similar lenses.

Most cameras allow to manually change the aperture by putting the camera in “A” mode – while you are changing the aperture the camera will automatically set the shutter speed accordingly. Some cameras allow you to manually set both aperture and shutter speed.

In conclusion shooting dramatic blurry background photos is easy with some minimal understanding of depth of field and some experimenting.