Posts from the ‘Tips and Tutorials’ Category
Exposure
What is Exposure?
The Exposure Triangle - Changing the value of one element will require compensation from another.
Exposure is the total amount of light that is allowed to fall onto the cameras digital sensor or film.
There are three elements that make up an exposure:
Aperture: The size of the hole that lets light into you camera.
Shutter Speed: The amount of time that the shutter is open to allow light in.
ISO sensitivity: How sensitive the digital sensor or film in a camera is to light.
Past posts have been written about each of these elements and I strongly suggest you read about each one to get a good understanding of how they work.
Putting it all Together.
In order to achieve the right exposure each element needs to be balanced out, raise the shutter speed and you might need to use a wider aperture or a higher ISO to compensate. This is called the exposure triangle.
One way you can think of it is that a camera is like a bucket being filled with a garden hose.
There are three variables to consider,
The size of the hose and how much water it lets out (aperture)
The time that the hose is left running (shutter speed)
and the size of the bucket (ISO)
In order to achieve the right exposure the bucket needs to be filled to the very top, if its undefiled you will under expose and if you over fill you will over expose.
Taking a photo is like filling a bucket with water, you need to account for different variables to fill it up.
Say we want to use a fast shutter speed to take a photo of a moving object, well if we run the hose for a short period of time the bucket will not be filled to the top, so we need to compensate, we can use a hose that has a larger opening and lets more water out (open the aperture) or we can make the bucket smaller so that it gets filled quicker (raise the ISO)
It takes time to master exposure, but its necessary to have an understanding of how it works to achieve turning an idea into a great photo.
You need to understand how each of the elements work and how they effect each other.
For further reading to better understand the three elements of exposure check out some of our past posts:
ISO – a Beginners Guide
ISO – How it Works
This photo was taken at a high ISO, notice the grain in the detail.
Some times when we are taking photos we find ourselves in a low light situation where we cant get a fast enough shutter speed to get a sharp photo. You could try opening your aperture to alow more light in, or you could use a flash, but some times thats just not prefered.
One option we have to achieve a faster shutter speed is to increase the cameras ISO sensitivity.
What is ISO
The ISO sensitivity determins how sensetive the cameras sensor is to light. At a high ISO setting like 1600 the cameras sensor becomes more sensitive to light and thus does not need to be exposed to light as long.
You may remember when we used to shoot with film, there was certain film made for sports. What made that film ideal for sports was that it had a higher ISO sensitivity such as 400, so it could achive a faster shutter speed then normal film that might have a lower ISO such as 100.
The Negatives of High ISO
There are some negatives to using a higher ISO though. The higher you boost your ISO the more distortion or grain you can see in your images, sometimes this can be a good look but usualy you want to avoid this distortion. The distortion you get from high ISO is kind of similar to a radio, at a low volume the radios music sounds fine, but as you begin to turn it up louder you begin to hear distortion and imperfections in the audio. As you boost the ISO sensetivity you begin to notice distortion.
Now days alot of the newer, higher end digital SLRs have amazing ISO sensitivities that barely show any distortion or grain.
ISO 200
ISO 1600
ISO 200 Close Up
ISO 1600 Close Up
Suggestions
You should always strive to use the lowest possible ISO sensitivity to achive the best quality photos, here are some guide lines of what ISO to use in certain situations.
Bright Sunny Day, you will want to use your lowest ISO either 100 or 200
Overcast cloudy day, ISO 400 would be a good bet for an overcast day
Indoors low light, you would want to use an ISO between 400 and 800
Night Time, You can boost your ISO up to 1600 or 3200 but at this point you might want to look into using a tripod and a longer shutter speed to avoid harsh grain.
Shutter Speed Explained
What is Shutter Speed?
Taken at sunset at a shutter speed of 14 seconds. Photo By Patrick Skotniczny
To put it as straight forward as possible, shutter speed is the length of time that light is exposed to the film (or sensor) in your camera.
A camera works by having light exposed to its film/sensor. In order for a photo to be properly exposed (not to bright, not to dark) the cameras film/sensor needs to be exposed to light for a certain period of time. If its a bright sunny day with lots of available light, you will only need a very short or “fast” shutter speed to properly expose your photo. However if your in an environment were there is not as much available light, such as indoors or at dusk, you will need to use a longer shutter speed to allow enough time for your film/sensor to be exposed to light.
How Shutter Speed is Measured.
Shutter speed is measured in seconds, usually in fractions of a second 1/60th of a second is at about the speed that we can hand hold a camera without getting hand shake (blurriness from your movement) some people can hand hold a camera as low as 1/30th of a second (assuming there subject is not moving).
You’re generally going to want to use a shutter speed above 1/60th anything lower and you’re going to want to use a tripod to reduce camera shake. Some cameras will let you use a shutter speed as low as 30 seconds, this is great if your trying to take photos at night. Some cameras also have a bulb setting which allows you to press the shutter button to open the cameras shutter, then press it again when you want to close the shutter, this is great for shooting star trails (check out my posting on star trails) witch can require the shutter to be open for hours at a time.
Night Shot Taken at a Shutter Speed of 30 sec. Photo By Patrick Skotniczny
Shutter speed techniques.
By controlling your cameras shutter speed you can chose to freeze any movement with a fast shutter speed, or show movement by using a slightly slower shutter speed.
Lets take a look at the two photos below. Both consist of a similar subject, but have been taking using different shutter speeds. The first photo show a water fall taken at a fast shutter speed and its freezing the motion of the water falling. The second photo uses a slower shutter speed to blur the water as its falling to achieve a feeling of movement. Both are great photos but depict a different feel.
By controlling what our cameras shutter speed is we can effect what our images will look like, we can choose to use a fast shutter speed to freeze a moving object, or slow the shutter speed down to portray some movement or compensate for a dark environment.
Photo By dobieluvrs
Photo By roberto.valentini
Some things to try.
Try using a slower shutter speed and pan with your subject. - Photo By greekadman
Try taking photos of moving cars or children playing, start at a shutter speed of around 1/300th of a second, then move your shutter speed down gradually until you reach around 1/30th of a second. Notice how your photos come out, at 1/30th you’re not going to be able to get a sharp photo of a moving subject, but at around 1/100 try panning your camera and follow your subject as you shoot, see if you can get your subject sharp by moving the camera with them and make the background blur from your movement.
Feel free to post a photo demonstrating a slow shutter speed in our forum, or leave a link to your image!
Watch D-Town TV
D-Town TV
If your an novice, amateur or pro photographer you have got to check out D-Town TV hosted by Scott Kelby and Matt Kloskowski.
Each week they release a video with great digital camera tips and hands on demonstrations. The information you get out of watching this series is absolutely priceless, each week you will learn a new trick or two when it comes to digital photography.
AND ITS FREE!
Check it out at.. http://kelbytv.com/dtowntv/
Also check out Scott Kelby’s third annual World Wide Photo Walk
Check to see if there’s a photo walk in your area, if not then why not register one yourself!
Aperture Explained
How Aperture Works
aperture works by adjusting the size of a lenses aperture ring and the amount of light that enters your camera, if the aperture is wide open lots of light gets in, likewise if the aperture is small less light will get in.
How is Aperture Measured
Aperture is measured in “f stops” and as you can see in the chart below. At f/1.4 the aperture is wide open and as the numbers advance to f/8 the aperture gets smaller. Its confusing but remember the larger the F stop the smaller the aperture.
Whats the point?
Lets say its a bright sunny day and your taking a photo of a single flower, you take the shot and notice that the flower is in sharp focus but so is the background. Having the background in focus looks noisy and detracts from your main subject (the flower). Ideally what you want is for the flower to be in focus and for the background to be out of focus or blurry, thus making the flower stand out.
This is achieved buy adjusting your cameras aperture. If your in auto mode or “P” Priority mode the camera will automatically chose your aperture for you and if it a bright day the camera will chouse a large aperture such as f/16. A large aperture will give you a wide depth of field (both the background and foreground will be in focus) we need to tell the camera that we want a smaller aperture such as f/2 which will give us a “shallow depth of field” (your subject will be in focus wile the background will be blurry). We do this by switching the camera to “aperture priority mode” (“A” on a Nikon, “Av” on Cannon) once in aperture priority we can scroll through the F stops and choose whether you want a large or small aperture. Remember a large F stop such as f/22 will make a small opening thus making everything in focus, wile a small F stop such as f/1.8 will make only your subject in focus.
f/22
f/8
- f/2.5
So if we want to take a photo of a flower where the flower is in focus and the background is out of focus, we tell the camera to shoot at a low F stop, around f/2.
If we were taking a photo of a landscape where we want everything to be in focus, we tell the camera to shoot at a large f/stop such as f/22.
Aperture to increase speed.
Lets say your shooting a sporting event and you need a fast shutter speed to capture your moving subject, or your indoors and you need your shutter speed to be fast enough so you don’t get blurry hand held shots. By having your aperture wide open (small F stop) you are allowing more light to enter your camera, which means you can get a faster exposure/shutter speed. This is when a good “fast” lens can be handy (fast refers to how wide the aperture can get)
In closing..
This is a brief description of how aperture effects the images you take. I advise you all to go out there and have a go at shooting in aperture priority mode, that way you can control and decide on the depth of field as you need it. My camera is almost always set to aperture priority, that way I can quickly choose to include the background to some degree or keep the detail in the background if I want to. I can also quickly set the aperture to wide open if im in a tricky low light situation.
Give it a try and feel free to leave a comment with any questions or post some of your photos on our forum!
