Friday, November 8th, 2013

Depth of Field – how to use it in your photography

Once you  know how to achieve  different depths of field, the question then becomes when would you use this in your photography?

Once you understand how you can achieve different depths of field in your photography – the question then becomes when would you use this knowledge to craft better photos?

Portraits and a shallow depth of field

There are a number of situations where it is a good idea to have a shallow depth of field and one of these is for portrait and pet photography. In this case you will want to remove any distracting background from around your subject. When the background is cluttered or distracting, a shallow depth of field helps you to isolate the subject from the background.

To achieve this effect, you would do one of these things or a combination of them:

1    Use a zoom lens and zoom in to your subject,

2    Get closer to the subject, and

3    Set your camera to use a large aperture, such as f/2.8 – f/3.8.

When you do this, take care to focus carefully on the subject. One disadvantage of working with a very shallow depths of field is that the amount of the area in the image that is in focus is very small so if you don’t get your focus right, your subject will be out of focus. You need to make sure that what you want to see in focus is the area you are focusing on.

Photographing flowers and products

Another situation in which you may want to use a shallow depth of field is when photographing flowers. The closer you get to the flower the more likelihood the background will be attractively blurred.

In product photography, you may also want to get a shallow depth of field and you’ll find that in many cases, the shallower the depth of field, the more attractive the image is. The difference between a shallow depth of field and a deep depth of field can often be the difference between an attractive photograph and one that looks more like a snapshot.

Landscapes benefit from a deep depth of field

While a shallow depth of field is extremely attractive for portraits and many other types of photographs, when you’re shooting landscapes and cityscapes you will typically want the opposite to be the case and you will want a deep depth of field. For landscape photography, you’ll typically want everything in the image to be in focus.

When photographing landscapes photographers often talk about hyper-focal distance. The hyper-focal distance is the point at which you point your camera at to focus the shot so that everything from that point to infinity is in focus and, in addition, an area halfway from the hyper-focal distance to your camera is also in focus. The image shows you how this hyper-focal distance affects the depth of field.

For landscape photography, you’ll typically want to use a small aperture such as f/9 – f/11, a short focal length such as 17mm and be a good distance away from your subject. Calculating the hyper-focal distance then becomes the issue. In many cases, people simply opt to focus the camera at infinity as this typically gives good results without needing technical calculations.

Too much of a good thing

If you’re tempted to increase the depth of field by simply dialing down your aperture to the smallest possible size such as f/35 or so, think again. While it may seem that this will give you a very deep depth of field it can be counterproductive. At very small apertures an effect called diffraction kicks in and this can cause a decrease in quality in your images. Instead you need to find the sweet point at which the smaller aperture gives you a good depth of field but stop short of where it gets so small that light is diffracted decreasing the image quality.

DSLR vs Point and Shoot for controlling Depth of Field

When you’re looking to achieve different effects with different depths of field, you’ll find that a digital SLR will give you much better results than a point and shoot camera. The reason for this has to do with the relative sensor size of the cameras – the larger the sensor size – the more control you’ll have over the depth of field.

Understanding depth of field and how it impacts the images that you take is a key way that you can impact the quality of your images. Choosing the right option for each shooting situation and knowing how to set your camera to achieve the desired result will enhance your photos.

 

Helen Bradley

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posted by Helen Bradley @ 3:29 pm1 Comment links to this post

Tuesday, October 29th, 2013

Controlling Depth of Field in your Photographs

Learn what depth of field is and how your camera settings affect it

Some subjects need to be fully in focus to be shown at their best and others need dreamy out of focus backgrounds to create the right setting. The feature that is key in both situations is called depth of field – it gives you both that ‘everything in focus’ look and it also gives you soft out of focus look. Depending on what you are photographing getting the depth of field right is often the difference between a snapshot and great image.

I’ll explain what depth of field is and how to control it with your camera settings.

What is depth of field?

At its simplest, depth of field is the zone of sharp focus in front of, around and behind the subject in your photo when you are focused on that subject. When you have a shallow depth of field, only a small area around the subject will be in focus and quite often only a small part of the subject will be in focus. Everything else in the image will be out of focus with things further away from the subject, either in front of or behind the subject, being more out of focus the further away they are. This image has a shallow depth of field – it’s a great way to shoot flowers:

When the depth of field is deep, nearly everything in the shot is in focus. You control the depth of field in your images by adjusting the camera’s settings for aperture, adjusting the focal length of the lens and the distance you are from the subject. This image has a deep depth of field – that’s important as we want to see everything in this scene from the grass in front of us to the horizon miles and miles away.

Let’s look at each of these in turn.

Control depth of field with aperture

One way that you can control the depth of field in an image is to change the aperture that you are using. For this, you will need to have your camera set to Aperture Priority or Manual mode. Selecting an aperture that is very large, such as f/1.4 to f/2.8 will give you a shallower depth of field around your subject. The aperture used for this image was a huge f1.4 so only a small portion of it is in focus:

 

If you shoot with a small aperture, such as f/9 to f/11 or more you will find that more of the image will be in focus, which gives you a deeper depth of field. If everything else stays the same, the difference in the aperture setting you use can result in a very different image. The aperture used here was a small f11:

One benefit of shooting with a large aperture, such as f/1.4 to f/2.8, is that a lot of light is getting into the camera so you can use a fast shutter speed. Conversely, a down side of shooting with a small aperture such as f/9 to f/11 or more is that less light gets into the camera so you will need to use a slower shutter speed  or a higher ISO value. In some cases you will be shooting with such a slow shutter speed that you will need to use a tripod.

Control depth of field with focal length

The focal length of your lens can also have an impact on the depth of field when you use this to make a subject bigger. So, if you are shooting with a 50 mm lens, you will get a much deeper apparent depth of field than you would if you were capturing an image with a 200 mm lens at the same aperture and if, in both situations the subject size is the same. The depth of field is actually not significantly different but it looks different because there is more background in an image when you capture it with a 50mm lens than you will get when you capture it with a 200 mm lens. So a rough rule of thumb is that the more zoomed into the subject that you are, the shallower the depth of field will appear to be. This giraffe was shot at f5.6 which isn’t a particularly large aperture but it was shot at 300mm zoom so the giraffe is quite sharp and the background is nicely out of focus:

 

If you are shooting landscapes you will get best results when you use a short lens such as a 28 mm lens as the image will appear to have a much deeper depth of field. On the other hand, a zoom lens can be a good lens to use when shooting portraits because the further you’re zoomed in to the subject the less background will be in the image and the shallower depth of field you will appear to have. This image was shot at f11 with a 28mm lens so everything from the lamp post to the building is in focus:

Control depth of field by varying the distance from your subject

The distance between the subject and the camera is another way that you can impact depth of field. So, for example, if you photograph a subject close up, such as in the region of up to 10 feet away, then the depth of field will be much shallower and more of the image behind the subject and a little in front of the subject will be out of focus. On the other hand, if you move the subject further away from you so that the subject is 20 feet away then the depth of field will be much deeper and there will be a lot more of the image in front and behind the subject in focus. This image was shot with a 200mm lens – the singer was relatively close to the camera  and the background was some distance behind him so the musician is in focus and the background nicely out of focus:

Whenever you’re considering depth of field, you should also note that, when the subject is in focus, the amount of the image that is in focus behind the subject will be greater than the amount of the image that is in focus in front of the subject. The ratio is approximately one-third to two-thirds, so the depth of field will extend roughly one-third in front of the subject and two-thirds behind the subject.

Helen Bradley

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posted by Helen Bradley @ 9:03 am1 Comment links to this post

Wednesday, October 24th, 2012

5 Quick Tips to Improve your Photography Today!

If you want to add a quick boost to your photos, follow these five tips to take better photos today… and everyday!

Tip 1 – Get close to your subject

The single simplest way to improve your photographs is to move physically closer to what you are photographing. If you can’t get physically closer then zoom in close using your camera’s zoom.

This image was captured from the verandah of a house in the tropics so it was possible to walk up very close to the clump of bananas on the palm.

 

Tip 2 – Capture Close ups with Macro

When shooting an object close up, set your camera to its Macro setting which is indicated by a small flower – you can set it using either a setting on the camera itself or from inside its menus. Zoom all the way back out (macro and zoom don’t mix) and check that the camera is able to focus on what you’re shooting – if not, move further back a little and try again. Most cameras can capture shots using macro mode as close as a few inches from the object.

This flower was captured with a macro setting – one side benefit of this is that the background is thrown out of focus showing an attractive shallow depth of field.

Tip 3 – Follow the Rule of thirds

The rule of thirds is a tool for creating a dynamic composition for your image. To apply it, draw an imaginary tic-tack-toe board over the scene you see in the  camera’s LCD screen or the viewfinder before you take the shot. Position the subject of the image along a horizontal a vertical line or at the  intersection of the lines. This ensures, for example, that the  horizon appears across the top or bottom third of an image and never right in the middle.

In this image the out of focus wall in the foreground is along the bottom line of the imaginary tic-tac-toe board.

Tip 4 – Capture from an Unusual Angle

Look for different angles to shoot from. Take a portrait  from a vantage point high above the person and look for different angles when photographing classic buildings so you  capture photographs that aren’t the same as everyone else’s.

In this image the camera was positioned under the flower and facing the sky and the translucency of the flower shows beautifully.

Tip 5 – Respect the “no flash” zone

The effective radius of your camera’s flash is around 9-12 feet so it won’t work in a sporting stadium at night. Instead use a long exposure time and mount the camera to a tripod.

In the image below the short radius of the flash has lit the statue which is close to the camera. A long exposure has captured the light on the structure behind. Read this post to discover how setting a curtain flash lets you combine both flash and long exposures.

 

Helen Bradley

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posted by Helen Bradley @ 10:26 amNo Comments links to this post