Basic of Camera

In this article we will discuss about the basic of camera. Did you know how camera can capture the image? In this article we will talk about this matter. But notice that all of content in this article are just my opinion. I just talk about my little understanding about camera. So if there are something wrong please make correction. You can write comment to make all clear.

Okay, lets talk about the part of camera. Look at the picture below

Basic Diagram of Camera

Here are the brief explanation. Objects can emit light with a specific pattern corresponding to that object. That light will be captured by the lens and enter into the camera. That light will pass through a small hole called the aperture. Next, the light will pass through Sutter. Sutter can be described as a window that can open and close. Next, the light will touch the sensor surface. The pattern on this light will be recorded by the sensor. Next, sensor will convert the pattern into an electrical information. Next, the level of information will be strengthened by an amplifier (ISO). Next, the information will be processed by the image processor and compress it into a jpg file. Finnaly, the file will be stored in the memory.

Many of pocket camera and SLR camera support full automatic mode, semi automatic mode and full manual mode.

Full automatic mode, all of camera element setting already done by camera. The main purpose of this mode is to produce clear and sharp image. So this mode is often use flash to ensure the object can be captured clearly.

Semi automatic mode, we can decide some setting like exposure, ISO, sutter, aperture, and flash but we can not decide all elements at the same time. There is two mode of semi automatic mode, they are sutter priority and aperture priority. So when we decide the sutter speed value, the camera will decide the aperture value. But when we decide aperture value, the camera will decide the sutter speed value. At this mode we can still easy to control the exposure level. The camera will attempt to reach the exposure targets that we have set before.

Full manual mode, we can decide all of camera elements setting at the same time. But we can not control and set the exposure level. Camera will not attempt to reach exposure target because there is no exposure target at this mode. The result of exposure level is depend from combination light, ISO, sutter and aperture which are we set before. This mode can be use to produce non standard image and suitable for advanced photographer.

Another basic of camera elements which should be notice are:
1. ISO
2. Sutter speed
3. Aperture
4. Flash
5. Exposure
All elements above will be discussed at another article at this blog.

Tag: Basic of camera, full auto mode, semi auto mode, full manual mode 

Aperture

Aperture is one of the important factor which will affect the exposure level of an image. What is the definition of aperture? My simple answer is "the large of hole that would limit the amount of light entering the sensor". At SLR camera, the aperture is located at the lens. It is a hole that the hole size can be set so that the light reaching the sensor can be limited.

To be continue

Sutter Speed

In an article titled Exposure Level has been discussed about the factors that influence the level of brightness of an image. One of the main factor that influence the level of image brightness is Sutter speed. What is Sutter speed? The simple answer is "the time which is required for the sutter to open".

One important component of a digital camera is Sutter. Sutter can be described as a door or window that can open and close. Sutter is placed between the lens and sensor, which is the way to entrance of light from the outside toward the sensor. The duration of Sutter opened can be set and controlled by the camera. The amount of light entering the sensor is determined by the time (short or long) of sutter when open. The longer time Sutter open, the light entering the sensor will be more and more so the resulting image will be brighter. To produce good image, the time setting must be precise. If too short, it will produce under exposure image. But if too long, it will produce over exposure image.

Here are the simple explanation how sutter work:
1. Before we push the capture button, the sutter still close. The light can not reach the sensor.

Step 1. Sutter still close

2. When we push the capture button, the sutter will open. The length of time when Sutter is open is depend with the settings that have been set. When sutter is opened, the light from outside can reach the sensor. The light will burn the sensor. This is the process of recording images. If sutter open in longer time, then the sensor will get more burned, so the result of images recorded will be more bright.

Step 2. Sutter open, light can reach the sensor

3. Next step, the sutter will close again. The light can not reach the sensor. The burned sensor will produce a certain pattern according to the light reaching the sensor. Here is the image that has been recorded. Then this pattern will keep in memory of the camera.

Step 3. Sutter close, image already recorded

Notice this explanation:
If we set the sutter speed on our digital camera with value of 100, it is mean that the sutter will take time 1/100 second to open. It is very short time. The duration of sutter when open will affect to the quantity of light which reach the camera sensor. Another setting are 500(1/500 second), 250(1/250 second), 125(1/125 second), 60(1/60 second), (30(1/30 second) etc. These kind of sutter setting is depend on camera.

Sutter settings can also be used to describe the effects of freeze and moving objects. If we use high sutter speed then we can freeze the effects of a moving object. Conversely, if we use a low sutter speed we can show the effect of motion of a moving object.

Look example below:

High sutter speed

High sutter speed

Picture above show the effect of high sutter speed which can be used to freeze the fast movement object

Low sutter speed

Low sutter speed

Picture above show the effect of low sutter speed which can be use to indicate the moving objects.

So the value of sutter speed setting decision is depend to our image theme. In some situation we need to use high sutter speed setting but in another situation we need to use low sutter speed setting.

The more detail about sutter speed will be discuss at another article with title Sutter Priority (will release soon)

Tags: Sutter speed, freeze effect, moving effect

Over Exposure

Over exposure is a condition in which the image brightness level is too high so that the image looks very bright and image detail is lost in bright areas. Over exposure could be caused by several things including:
1. Over lighting conditions.
2. Sutter speed setting is too slow cause sensor absorb light in long time.
3. Aperture setting is too big cause sensor absorb too much light.
4. ISO is too high cause light amplifier produce high gain.

How do I prevent over exposure? Here are some ways you can do:
1. Always use the camera in full automatic mode.
2. If you prefer the manual mode, then make sure you always pay attention to indicators of exposure on the camera. If the position indicator does not do a correction in the middle of the exposure by adjusting the aperture and sutter speed.
3. Use ND filter to reduce the light.

If the image was already in a state over exposure then it should be done to improve the image that is using picture editing software such as Photoshop. I will explain how to fix image over exposure using Photoshop. This is not the only way. This is just a simple way. Perhaps there are many other better ways. Follow these steps:

1. Open your over exposure image in Photoshop

2. Check the hystogram. On the main menu click Image >> Adjustments >> Levels

3. The graph above shows the condition of your image hystogram. Notice the two red circles. Try to move the two red circles to the right a little. You will find the changes. What do you think? Did you get a better picture now?

4. Now press OK and save your picture.

There are a few tips when shooting. If you use a SLR camera, you should not choose the jpeg file to store the images in the camera. RAW file format gives better results than the jpeg. RAW image format is not compressed so that when you experience the process of editing will produce a better image. But RAW has a risk that the file size is very large and thus require the storage media with larger capacity. Further details about the RAW will be discussed in another article.

So do not worry about over exposure because with good image editing it's not a problem anymore.

Tags: over exposure

Under Exposure

Under exposure is a condition in which the image brightness level is too low so that the image looks dark and image detail is lost in dark areas. Under exposure could be caused by several things including:
1. Poor lighting conditions.
2. Sutter speed setting is too fast.
3. Aperture setting is too small.
4. ISO is too low.

How do I prevent under exposure? Here are some ways you can do:
1. Always use the camera in full automatic mode.
2. If you prefer the manual mode, then make sure you always pay attention to indicators of exposure on the camera. If the position indicator does not do a correction in the middle of the exposure by adjusting the aperture and sutter speed.
3. Use adequate lighting by using light or flash.

If the image was already in a state under exposure then it should be done to improve the image that is using picture editing software such as Photoshop. I will explain how to fix image under exposure using Photoshop. This is not the only way. This is just a simple way. Perhaps there are many other better ways. Follow these steps:
1. Open your under exposure image in Photoshop

2. Check the hystogram. On the main menu click Image >> Adjustments >> Levels

3. The graph above shows the condition of your image hystogram. Notice the two red circles. Try to move the two red circles to the left a little. You will find the changes. What do you think? Did you get a better picture now?

4. Now press OK and save your picture.

There are a few tips when shooting. If you use a SLR camera, you should not choose the jpeg file to store the images in the camera. RAW file format gives better results than the jpeg. RAW image format is not compressed so that when you experience the process of editing will produce a better image. But RAW has a risk that the file size is very large and thus require the storage media with larger capacity. Further details about the RAW will be discussed in another article.

So do not worry about under exposure because with good image editing it's not a problem anymore.

Tags: under exposure

Exposure Level

Exposure level can be interpreted as an image brightness level. Exposure is one of the factors that need to be noticed in the process of taking pictures as it will greatly affect the quality of an image. In general there are three kinds of levels of exposure. They are under exposure, normal exposure and over exposure. Here is a picture as an example of exposure.

3 exposure levels

What do you think? Which one is the best?

Under exposure will cause the resulting image is too dark, so we'll lose image detail in dark areas. Over exposure will cause the resulting image is too bright, so we'll lose image detail in bright areas. Normal exposure will produce a balance in areas of dark and light so that we will get good detail in dark areas and bright.

In photography, exposure is affected by three main factors. These three factors are often referred to as the triangle of exposure. Three factors are:
1. Sutter speed
2. Aperture
3. ISO setting

Exposure Triangle

Three factors above are influenced by the existing facilities at the camera. SLR camera have better facilities when compared with a pocket camera. A brief explanation of the effects of three factors are as follows:
1. "Fast Sutter speed" produces a dark image, "slow sutter speed" produces bright images.
2. "Small aperture" produce dark images, the "big aperture" produce brighter images.
3. "Low ISO 'produces dark images," high ISO "produce brighter images.

Exposure indicator on the camera is usually described as below:

Exposure indicator

If the position indicator in the middle (0), it is called a normal exposure, if on the left side (-) then it is called under exposure and if on the right side (+) then called over exposure.

In the operation of the camera using full automatic mode, exposure indicator will always be in the middle (normal exposure) because this position is the default position of most of the cameras. Any brand camera will have a different image characteristics despite similar exposure indicators. For example, "KODAK" has brighter image characteristics, but "CANON" tend to be darker and cool (sorry, this is just my personal opinion).

In certain conditions would be very difficult to get a normal exposure. For example when we take a picture of an object with a very bright background. In this case we must have a priority because the camera is just a machine that is not as good as the human eye. If our priorities on the object then the camera will choose to use a slow sutter speed or big apperture or high ISO. This setting will produce a detailed image on the object but as the risks will result in over exposure in the background. Conversely, if our priorities in the background then the camera will choose to use high sutter speed or small aperture or a low ISO. This setting will produce a detailed image in the background but as the risk will result in under exposure to the object.

This above is a serious problem in the field of photography because the details on all aspects of the images are often necessary. But along with technological developments of digital image editing, the above problems have been overcome. There are several software that are categorized as high dynamic range software which are capable of overcoming the limitations of the camera exposure problem. Some software such as Adobe Photoshop, Dynamic Photo HDR, Photomatix, and many more use digital manipulation has proven to give good results. So with this software is no longer exposure problem on digital cameras.

Tags: exposure, brightness, photography, digital cameras