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If you put your camera to the T or S setting (for Time or Shutter speed), then you are wielding control over the shutter speed. Usually, on a Digital SLR camera, when you depress the shutter release button to take a photograph, the mirror moves up out of the way and the shutter opens for a split second, closes again and then the mirror comes back down to it’s original position. When the shutter is open, it allows light through the aperture to the sensor so that it will be exposed to light and record what is there.
If you have the shutter open for a long time, then obviously a lot of light will get in. If you have the shutter open for a short time, then much less light will get in. To see how it works, close your eyes and quickly open and close one of them. You won’t see much detail. If you leave your eye open for longer, then you will get a much better view. Now, your eye has to focus too, but you get the idea.
The time needed to record an image in daylight is quite short. We’re talking fractions of a second here. When your camera is on the T setting, you can adjust the lenght of time that the shutter is open. This might range from 1/3000 second through 1/1000, 1/500, 1/100, 1/60, 1/10, 1/2 (with others too) all the way to 1 full second. Then it goes out the far side and goes to 1.5, 2, 5, 10 seconds etc. On a normal enough day outdoors, you will probably use in the region of 1/250 or more. If it is darker, then you will need a longer time – e.g. 1 second or more for a night time shot.
When the camera is set to use slower than 1/100, or maybe 1/60 if you are very steady handed, then you will need to consider using a tripod or platform to support the camera as your breathing, heartbeat, finger pressing the button and other vibrations in your body will move the camera enough to blur your shot. In fact, if I am going for a long exposure, I will usually use the self timer or a remote control to make sure that my finger pressing the button doesn’t affect the taking of the picture. On a 2 second self timer, my finger is away and the camera has stopped moving before the picture is taken.
So, why would you want control over your shutter speed and when would you use it? The main times that I would do it are when I am taking landscape or sky shots when it’s dark. If you take a picture of the sky at night with a 1 second and then a 10 second exposure, the results are very different. You can get a nice effect leaving it for longer. Another time I would select the shutter speed is if I am trying to blur a waterfall or moving stream. If the shutter is open for, say 1/10 second, that will blur it nicely. Another often used reason for controlling your shutter speed is if you are photographing a fast moving object – e.g. a car. If you have a slow exposure and the camera is stationary, then the car will be blurred because it is moving. By setting a fast shutter speed, e.g. 1/2000 second, then the car will be less blurred. Panning the camera with a slower shutter speed will keep the car clean but the background blurred if you want to go for that effect. This takes a bit of practice though.
As I mentioned in the Aperture section on this site, shutter speed and aperture go hand in hand. You need to be aware of this when manipulating your shutter speed. If you have a fast shutter speed, then the camera will automatically lean towards a large aperture (small number, e.g. F4.0). And vice versa. As a larger aperture gives you a greater contrast between in-focus and out-of-focus objects, you will need to consider this when framing and setting up your shots.
If you put your camera to the A setting (note, this is not the Auto setting!), then you are wielding control over the aperture. This means that you are controlling how wide the shutter opens. This is measured in f-stops. You can get technical in understanding exactly how this works elsewhere, but I’ll try to explain how it affects you. The kit lens for my Canon EOS (18-55mm) gives me aperture value settings on a scale from 4 up to 22. When I set the aperture to 4.0, the shutter opens widest, letting a lot of light in. When I set the aperture to 22, the shutter opens to a narrow setting, not letting much light in.
To practice what this means, compose a picture outdoors with the camera on Av and with F4 selected. Half hold your shutter release button and you will get a relatively fast shutter speed (e.g. 1/2000 second). This is because the hole is open wide and does not need to be open for long. Then change your aperture setting to the max – say, 22. When you compose this, you will get a slower shutter speed (e.g. 1/250 second) This is because the hole is smaller and needs to be open for longer to let the right amount of light in.
Both of these pictures should come out fine, but when you go indoors and there is less light around, what you choose will make more of a difference. If it’s darker indoors and you select F4, the camera might put the shutter speed to 1/100, because the hole is big and lots of light can get through in a short length of time. This should be fine but once the shutter speed starts going slower than 1/100 second or 1/60 second (if you’ve got a VERY steady hand), there is a chance of blurring the photo by slight movements in the camera. For the same indoors shot if you select F22, you might be down to 1/10 second (because the hole to let light through is very small) and this could make taking a picture without a tripod unfeasible.
The other extreme can also happen if you select F4 when outdoors. If it is very bright, then your camera’s shutter speed might not be fast enough to open and close without over exposing the shot. My camera doesn’t go faster than 1/4000 second and using F4 on a particularly bright day can over expose shots.
This is all well and good and interesting and will help you decide what you need for shots in particular light situations. However, it really becomes interesting when you are being creative with your aperture settings. In addition to allowing different amounts of light in, different aperture settings change the focal length of the lens. Again, I won’t try to explain the physics behind this, but go straight for how it affects you. If you go for a close-up shot of, say a flower, you can choose how much of the picture you want to be in focus. If you choose F4 (or lower, if your lens allows it), then that brings only very small percentage of the view into focus.
Here is an example of this. I have a nifty fifty lens that goes down to F1.8 and I used it to take a picture of my baby son.
You will note that his face is in focus but the background is out of focus. In fact, even the collar of his top is beginning to be out of focus. This really brings the intended subject of the photo to the fore and to your attention.
If you are taking a landscape shot, chances are that you will want more of the scene in focus. If you move the aperture setting up to a high value, you will get more of the scene in focus.
Here is an example of a shot that I took of a lake near Dublin. It is set at F19 so the foreground and the background are both quite in focus and recognisable.
Photography is all about light and using it to your advantage. Light needs to hit the sensor for it to record the scene in front of it. The amount of light that hits the sensor will dictate the look of the picture…bright (over exposed) / dark (under exposed). The 4 main things that affect this are: Ambient light (there might not be much you can do about this); Aperture; Shutter speed; ISO. Aperture and shutter speed go hand in hand but ISO is a bit different so I’ll deal with that separately. If you set the camera to Aperture Value, you can modify the aperture setting manually and the camera will deal with what the shutter speed should be. Conversely, if you set your camera to the Time Value (otherwise known as shutter speed priority), the camera will determine what your aperture settings will be. I haven’t got my head around when you configure both aperture and shutter speed, so I’ll come back when I do!
Over the next week or so, I hope to put some thoughts together on tips for using some features of a DSLR camera or a non-SLR camera that lets you at some more advanced settings. I’ve read a couple of photography books and read several Internet articles and have often found them to be a bit unclear and difficult to properly understand. Through re-reading these and practicing, I feel that I’ve gained a bit of an appreciation for how to use some of the features to improve my photography. I aim to explain them in a non-technical manner with examples to show what different settings do. I’m no expert but hopefully I’ll be able to provide some insight to beginners to encourage you to try out these features and take more control of your shots.
Specifically, I plan to look at the following:
– Aperture Priority
– Shutter Speed (Time) Priority
– White Balance
I may think of more or add more, but that’s the plan for now.
We’re back with the live weather updates. I had to take it down because a new member of the family arrived (little Cillian) and I needed to move the receiver for my weather station into the bedroom beside him so I could keep an eye on the room temperature. Now, I’ve got another thermometer doing that job so I have put the weather back online. Good! To see it, see the My Weather Station button on the right.
I’ve had to take the live weather updates down as I can’t guarantee that the weather station will be connected 24 x 7. Sorry about this.
It seems that I didn’t have the detailed page setup quite correctly. I’ve corrected this, so it reads a lot better now. Not only this, but the gauges are now complete.