MAKE GREAT PHOTOS

Have you bought an expensive camera and keep shooting in auto? I'm sure you can take good pictures in auto but to make great photos you just need to get out of auto. Below I have shared some basic tips to help you get to the next level. Once you understand these basics of photography you can use it to create the artistic style you want and to always get the correct exposure. Then you will never go back to auto.

APERTURE

The aperture (also called f-stop or f-number) decides the opening size (diameter) of the lens and how much light is let in through the lens, much like the pupil in your eye. The aperture is controlled by a number of aperture blades inside the lens and can typically be varied between f/2.8 (wide) to f/22 (narrow) but the maximum aperture varies with different lenses. Lenses capable of wider apertures (low f-number) are generally more expensive and lets in more light, these are often referred to as faster lenses as you can use a faster shutter speed to get the same exposure. This may be required in low-light situations, such as evenings or indoors without flash. A wide aperture can also be used to create a short depth of field for a subject in focus and a blurred out background (bokeh), this is often used for portraits.

A narrow aperture (high f-number) can be used for photos where a long depth of field is desired e.g. for landscapes where you often want foreground, middleground and background all in focus. A narrow aperture can also be used to create star bursts. It might be confusing that the widest opening size is at the lowest f-number. This is due to that the number actually is the ratio between the focal length and the diameter of the opening size of the lens. So if you shoot with a 100 mm focal length at f/4, the diameter of the opening in your lens is 100/4 = 25 mm.

Shutter speed

Shutter speed (or exposure time) is the amount of time the camera receives light to the image sensor. The longer the shutter speed, the more light is received by the sensor. It is typically measured in parts of a second but can be varied between several seconds to thousands of a second. In most cameras, the shutter speed is controlled by shutter doors covering the image sensor much like normal window shutters.

The shutter speed affects how the subject is captured with respect to motion and camera shake blur. A fast shutter speed can be used to freeze motion and minimise motion and/or camera shake blur. Motion blur appears when the subject, or a part of the subject, moves during the exposure. Camera shake blur occurs when the camera moves during the exposure and appears over the entire image area. To avoid camera shake blur you can:

• make sure you hold the camera steady or use a tripod
• use image stabilisation in the lens or camera body
• always use a shutter speed equal to or faster than your focal length

Both motion blur and camera shake blur may be used to your advantage. Motion blur can for example be used to create silky water or to smooth out waves. Camera shake blur can be used for example when panning, following your subject during exposure to get a subject in focus and a blurry background that creates a sense of movement.

"Natural shutter speeds" that match the human eye and the way the brain perceive the outside world is about 1/30 second to 1/125 second. All shutter speeds that are shorter or longer than this show the world in a way that we cannot see without the help of a camera.

ISO

While aperture and shutter speed both decides how much light is received by the camera sensor, ISO decides the light sensitivity of the sensor recording the image. A low ISO means low sensitivity and that the sensor needs more light to record a well exposed image. When using film, each roll has a specific ISO-value but with digital photography, the sensor is your film and you can adjust the ISO as you please. Most digital cameras has a base ISO of 100 and typically goes up to 6400 although a few newer professional cameras can go a lot higher.

Every time you double the ISO value, you also double the sensitivity of the sensor or in other words increase the sensitivity by one stop. Image quality is always best at lower ISO's as the sensor uses more light to record the image. Using a high ISO value may introduce noise/grain or give dull colors. A high ISO may also decrease the dynamic range which is the sensors ability to capture details in shadows and highlights. However, modern cameras can often produce good quality photos even in high ISO values which may be required in low-light situations such as evenings or indoors without flash. Shooting in low-light situations without artificial lighting, you may find yourself using the widest possible aperture and the slowest shutter speed you can shoot hand-held with and still get a sharp image. If you're at this point and your images still comes out under exposed (too dark), your only choice is to increase the ISO. Remember that a grainy sharp image is always better than a smooth blurry image. This can also be used to create moody images.

Understanding EXPOSURE

Now you have learned the basics about aperture, shutter speed and ISO which often are referred to as the exposure triangle and together creates the exposure for your photos. The settings affect the brightness of the image and understanding these fundamental settings is key to any photographer so I hope you learned from the above. The only way to master it though is to get your gear out and practice. Photographer Tony Catalano has created an interactive exposure tool which is great for understanding how aperture, shutter speed and ISO work together to create the exposure value.

Another way to look at the exposure triangle is with the faucet analogy: Say you need X amount of light to create a perfect exposure, or in this analogy, X amount of water. How much you turn the handle (flow rate) resembles the aperture, the time of which the tap is on resembles the shutter speed and the size of the container to be filled resembles the ISO. This analogy is explained by Pye Jirsa from SLR Lounge in the video below.

I've been talking a lot about exposure above and you might wonder; how do I know I've got the right exposure? This is where the histogram comes in! A histogram is a graph representing the exposure value of the image and you can find it in most cameras and usually in the top right corner in most photo editing software. It ranges from the deepest shadows (left) to the brightest highlights (right). In most cases, you want a fairly even distribution but it depends on the brightness of the subject. If you are shooting a snowy landscape on a bright day you want an over representation to the right in the histogram, if you are shooting a portrait where the subject is wearing black clothes against a black background you want the opposite. What you don't want is the histogram to touch either side as this will mean that you either over or under exposed the image.

Check out this video by photographer Karl Taylor for a better understanding of histograms:

Do you ever wonder why snow often turns out grey or why your black suit looks grey on most of your photos? Well, now that you know how to interpret histograms, one of the biggest reasons to get out of auto is that the metering system in your camera wants to turn the exposure into medium grey, which sometimes (quite often actually) isn't what you want. This especially if you are shooting an overall bright or dark image. To get the correct exposure in these situations, you need to use exposure compensation which isn't available in full auto mode. The metering mode also plays a role in this as explained in this great video by Tony and Chelsea Northrup about exposure compensation and metering modes.