Technologies: How Digital Cameras Work

Flash Unit

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The above Speedlite EX320 from Canon is a type of flash unit, which is attached to the camera hotshoe.

For digital photography, flash refers to a type of light with the super strong brightness which is needed for illuminating a shooting scene or freezing objects that are quickly moving. There are two types of flashes, in which the first is the light from the flash unit and the second is the electronic unit that actually creates the light.

Flash Unit in Digital Cameras

Flash Unit in Digital Cameras

The color temperature of a flash of light is about 5500k (short for kelvins). The duration of burst of light ranges from 1/1000th to 1/200th of one second

Modern flash light needs to be powered and the power comes from single use flashbulbs. Originally, flammable powder was used to provide the power! You’ll find some various types of flash. Commonly, there is a built-in flash unit in solid digital cameras. And, at times you can find built-in “pop-up” flashes in DSLR cameras. Usually, the pop-up flash is a little bit weak. Therefore, a hot shoe is often available in all DSLR cameras so that you can attach an exterior flashgun to this hot shoe (this accessory is positioned on the camera top panel).

Photographers at the professional level often use independent flash units, referred as to studio lights. You can power these flashes by battery packs or outlets.

You often find a tube with electronic flash and this tube is full of xenon gas. The electrical arc is generated through the process in which high voltage electricity has been discharged. Then, a short flash of light is emitted by this arc. You will find an instruction number that shows the strength of a specific flashgun.

Understanding Image Sensors of DSLR Cameras

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A digital camera uses an image sensor for capturing the information. To understand the image sensor in the simplest way, its function is equivalent to that of a film piece. When you press the shutter button on your DSLR, you are allowing the light to come into your camera and strike the image sensor to perform the image exposure. This is similar to the way in which an image is under the exposure onto a film piece that you could find in an old 35mm film camera.

What are CMOS and CCD?

There are commonly two kinds of image sensor that you can find in both point and shoot cameras as well as DSLR models, including: CCD and CMOS.

In an image sensor, there are some certain pixels that are used for collecting photons (energy packages of light). Then, the photodiode will convert these photons into an electrical charge which is turned into a digital value through analog to digital converter (AD converter). Through this converter, the camera will carry out the processing task on these values and create the final image.

For CCD (short for Charge Coupled Device) sensors, a circuitry around the sensor is used for converting pixel measurements continuously. CMOS (short for Complementary Metal Oxide Semiconductor) sensors operate in the different way in which pixel measurements will be converted simultaneously and the circuitry is right on the image sensor. Between the two above types, CMOS sensor is more commonly used because its speed is faster and you have to spend less to buy such a sensor.

Image Sensors of DSLR Cameras

Image Sensors of DSLR Cameras

Color Filter Array Sensors

This technology is commonly found in most DSLR cameras in the current market. A color filter array is positioned on the top of the image sensor to record the green, red as well as blue elements of the light that comes into the image sensor.

Therefore, every single pixel just can measure only one color, and the image sensor will base on the surrounding pixels to estimate the remaining two colors. The image quality can be a little bit affected, but you won’t be able to see this in the modern cameras which offer the high amount of resolution.

Foveon Sensors

There are three basic colors that are the most sensitive to your eyes, including green, blue and red. Other colors have been created by a mixing of the basic colors. In the film photography, the various basic colors had the exposure on the equivalent chemical film layer. In the similar way, there are three layers in Foveon sensors in which each layer measures one basic color. The above three sensor layers have been combined to create a mosaic of square tiles to form an image. This technology is pretty new and currently, just Sigma applies this technology only.

Understanding Camera Menus

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You may not pay much attention to the difference, but one nice advantage of digital cameras compared to film cameras is that you can have more control over the settings in digital models. You can control the menus on the LCD screen of a digital model which you have never experienced with a film model.

And the manufacturers nowadays focus a lot on the kinds of commands that are included in the different menus. There are many different screens and the ways of organizing these screens are diverse, so you may find it slightly confusing in learning how to use them. In addition, with some digital cameras, the ways of organizing the menus are not the same for all shooting modes that even get you more confused.

The below listed tips will be useful for helping you learn how to make of the camera menus better. Thoroughly find out this nice feature to have the photography results as you want.

  • To have the menu opened, just find the menu button on the camera back panel. You will see the word “MENU” to indicate a menu button on several cameras, while in some others, there will be an icon which is displayed in the similar shape as an outline of bullet points. If your camera is touch screen camera, the Menu button is often found on the touch screen LCD.
  • The menu can be structured in 2 ways. The first one is that you find all of the control settings of a camera are located under the Menu button and there is not any category. In second one, you may find different categories in the menus, and you will see the controlling settings of each particular category when this category is selected. The second way is more popular.
  • If the menu of a digital model is organized into categories, you can quickly get access to the feature that you want to use, which is very nice for saving plenty of time. For instance, when you need to clean the camera sensor or configure the date, you will want to get direct access to the Setup menu, not the Shooting or Playback menu.
  • Additionally, you may find the menu category displayed by icons. For instance, you may find the Setup category or the overall settings menu in the shape of a “wrench” icon. First, have the needed menu icon highlighted; later hold down the OK/Enter button or the button in the shape of the right arrow to start selecting the commands. Finding out the meaning of each category icon shall help you select the functions faster.
  • For several camera menus, you may find some commands not available or “grayed out,” based the shooting mode or the function that you have just selected. In case that you want to have an unavailable command operated, it requires that you change into another shooting mode in which that mode supports this command.
  • To stop using the menu features of a digital model, you can hold down the Menu button, or for some certain cameras, you may hold down the shutter halfway. There may be also a Back button in a camera that you press to get back out of the menu area.
  • With a digital camera that offers a touch screen, it is much easier to use the menus. You only need to touch the command that you want in the menu. There may be a Back button or you can find the Exit button in cases of returning to the Shooting mode. The way that you used a camera touch screen is pretty similar to the way you use a smart phone, in which you just need to drag the fingers over the screen to scroll over the options of the menus. This is more popular than using a button of four ways.
  • Several models – especially high-end DSLR cameras – enable you to have the customization capability on the options of the menus. For instance, you can set a shortcut for a commonly-used command through making use of the “customized menu” or “my menu” selection. At times, you a Custom button is also available.

Photography Noise?

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If you have used a digital camera for a certain period of time, perhaps you will be not strange to the term “noise”. So, what is the shooting noise? And how does it affect your photos?

What Is Noise?

To explain it in a simple way, noise is represented by undesired color specks on your photos. The color of the image is often different when there is noise. For example, you may see pink specks on grass of the green color. Commonly, you find the noise appear like grain on a photo.

What are the causes of noise?

It is pretty common that the higher ISO setting in a DSLR camera causes the noise in the photos. In addition, too much heat also causes noise, which is called “thermal noise”.

When you set the ISO number higher, there will be a larger amount of light for your photos. However, the noise will certainly appear, which is common for any electrical systems. And, as you find the light weaker, signals have been amplified and consequently, you have the noise amplified accordingly.

Why is noise reduced in some DSLR cameras?

Firstly, if you want to know how a DSLR minimizes noise level, you need to have a clear understanding of digital image sensor.

There are often two types of image sensor in digital models (for both compact models and DSLR cameras – they are CCD or CMOS sensors. The above two sensor are formed by a number of pixels, which can be considered as light sensor, which turn the light into electric charges. Analog signals will be sent through these charges to the camera A/D converter and converted into digital pixels.

The larger the camera image sensor, also known as chips, the less noise you will find with the images as a larger chip shows that the effective size of the pixels is larger, which results in less noise.

Consequently, when the size of every pixel is larger, you will find a smaller amount of noise. But, as related to this, a APS-C or crop frame camera has a larger amount of noise than a full frame model because the sensors of APS-C or crop frame models are smaller.

However, the digital technology is becoming better and better and the noise problem is further reduced with latest technologies

What Is Shutter Speed?

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It is not complicated to understand the definition of the shutter speed: It is the duration that the camera opens the shutter. The camera image sensor will receive a larger amount of light when the shutter is opened in a longer duration. With a shorter shutter opening, a smaller amount of light comes into the sensor.

When you completely understand how to use the camera shutter and the certain shooting situations in which the shutter should be changed, it becomes easier to use the shutter speed. What does shutter speed mean?

  • For the majority of time, the measurement of the shutter speed is a fraction of a second. A number of 1/500 shows you that the camera opens the shutter in 1/500th of a second only. However, you can lengthen the shutter speed to 30 seconds or even more. This is optional
  • For most digital models, you can find the speed options such as 1/1000th, 1/500th, 1/250th, or 1/125th of a second. It is common that the higher shutter speed settings increase about as twice as the speed of the previous number and decrease by about half the speed of the previous number
  • When you are capturing images in normal lighting conditions, the shutter speed can be higher and you find it easier to stop” the action. Under inadequate lighting conditions, perhaps the shutter speed needs to be slower.
  • A tripod is recommended to use for the situations that the shutter speed is not equal to or faster than 1/60th of a second. At this shutter speed, it is hard to keep the camera firmly in your hand in a long duration, which results in the image blurriness (known as camera shake).
  • The shutter speed can be set manually or you may refer to the “shutter priority” mode (you’ll often see the “S” abbreviation on the camera mode dial). When you use this mode, you have the shutter speed set in the first priority and then, other configurations will be properly set to work well with the selected shutter speed.
  • The shutter speed and the aperture (or f-stop) setting of a camera have a close relationship because the aperture settings decide the opening level of the lens. When the opening is larger, the camera will receive more light into the sensor and less light comes into the sensor as the opening is smaller. To say it in the most simplistic way, when the shutter speed is increased while the opening is larger, your image sensor shall receive the same amount of light. The trade-off is not always exact but you can understand the relationship between the two above settings in this way.

Choosing Best Camera Image Stabilization

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optical image stabilization - Camera Explained

optical image stabilization – Camera Explained

The image stabilizing technology is shown in this photo.

You often see the term “IS” that may be commonly attached to the end of your digital model name, right? If you don’t know what the “IS” stands for, let me bring you a pieces of explanations. IS, commonly found with a digital camera, stands for the terminology “image stabilization technology”. This technology is useful in reducing blurry photos from camera shake.

The image stabilization technology has been introduced for long and nowadays, this technology is included in more and more digital models aimed at the consuming level

Because nowadays IS has become more popular, you should at least find out about it before purchasing a digital camera. There are several different options of the IS technology in a digital model.

The three primary configurations of digital camera image stabilization are:

  • Optical image stabilization
  • Digital image stabilization
  • Dual image stabilization

The Basics

To lower the impacts of vibration or camera shake as much as possible, a software or a hardware will be used in the IS technology inside the camera body. When you use a long zoom or shoot photos without enough light, you tend to see more blur in your photos. In these cases, the camera has to adjust the shutter speed to be slower to help the image sensor receive a bigger amount of light. The slower shuttering speed is, the more shake or vibration you’ll find with your camera, which causes the blurriness at times. Even you yourself can cause a bit blur when you just slightly move your arm or hand.

Don’t expect the IS technology to help you completely avoid the blurriness. This technology may not work for the cases in which the moving speeding of a subject is too fast compared to the camera shuttering speed that you are selecting. But this IS technology is nice for reducing the blurriness that is caused by the pretty slow moving speed of a photographer.

(Sometimes, this problem happens for almost all photographers. So, don’t have the bad feelings). It is estimated by the manufacturers that you’re going to able to capture a couple of shuttering speed settings slower than you can without the support of IS.

If your camera does not offer a nice IS system, the shuttering speed should be raised, but this can cause some trouble for shooting photos under inadequate lighting conditions. If the IS setting does not help, another way to make the shuttering speeding faster in low light photography is to increase the ISO number

Optical IS

The optical IS (sometimes abbreviated as OIS) is preferred in solid digital models which is targeted at photographers at the beginning and intermediate levels.

In this technology, a hardware is used to minimize the camera shake. For different manufacturers, the configuration for performing the optical IS may be different, but you will easily find that for the optical image stabilization, there is a built-in gyro-sensor in most digital models. This gyro-sensor calculates every moving action of photographers. This measurement is transferred from the gyro-sensor to the CCD via a stabilization microchip and this CCD shall shift a bit to make the compensation. The image is recorded by the CCD, or also known as charge-coupled equipment.

Among the forms of IS, the most accurate one is certainly the hardware correction that you can find with optical image stabilization. The ISO number won’t be raised and the image quality will not be compromised.

Digital IS

Digital IS refers to the application of software as well as the settings of a digital model to negate the impacts of the camera shake. Certainly, the ISO which measures the sensitivity of a camera to light must be raised. If your camera has the ability to capture an image with a smaller amount of light, the shuttering speed can be set faster, which helps maximum lower the camera shake.

However, with the digital IS, the ISO has been often set higher beyond the common level of the auto setting. By this way, the image quality can be affected and the noise appears more in your images – noise is the number of pixels that have not been correctly recorded. I can say in another way that, forcing a camera to capture a photo with the ISO at the higher level compared to the optimal ISO settings may negatively affect the image quality, and that’s the manner of the digital IS.

The digital IS sometimes involves in using a built-in software to lower the blur as much as possible after the photo has been already taken. This is pretty similar to the situation in which you use a computer software to edit the photo. Anyway, digital image stabilization is still effective to some extends.

Dual IS

Dual image stabilization is sometimes not easy to pin down, because manufacturers have various definitions. Most commonly, the dual IS refers to the mix between using a hardware for stabilizing the image (as you can see with optical IS) and a higher ISO setting (as with the digital IS)

At times, dual IS shows a fact in which the IS technology is included with a digital SLR (single lens reflex) model in not only the camera body but you can find it in the interchangeable lenses as well.

Working Without IS

Sometimes, you cannot find any IS form in the older digital models. Without the image stabilization, you can refer to some of the following tips to help avoid the camera shake:

  • Attach a tripod to your camera
  • Instead of using the LCD, use the viewfinder for framing photos.
  • Lean against a door frame or a wall to keep yourself steady
  • Your elbows should be braced against your body side and it’s recommended to hold the camera with two hands.
  • Try to ensure the shuttering speed to be fast every time, but you cannot use this option all of the times.

Stay smart

Lastly, make sure that you do completely understand the way that the manufacturer tells you about the available IS feature. You may easily see some misleading listings such as “anti-shake” or “anti-blur” mode with the camera, but actually there is no IS offering at all. For these types of camera, the common solution for reducing the blurriness is to set a higher shuttering speed. But sometimes, this actions may cause you encounter exposure issues, hence affecting the image quality.

In addition, different manufacturers may have different brand names for expressing the IS technology, which may get you more confused. For instance, to say about the IS, you can see  the name “ Vibration Reduction” with some of Nikon models while for Sony models, the manufacturers used the word “Super Steady Shot”. Canon may choose another word like “Intelligent IS” to show you the available image stabilization.

Before making the purchase decision, you should be certain that the brand name refers to optical image stabilization, not some kind of digital IS. To avoid the confusion, you should find out more information from the official site of the manufacturer or a trusted salesman in the store where you buy the camera.

There may be the inclusion of the optical IS only or you can find some kinds of dual IS with your camera. But certainly, you don’t have to be as concerned as for buying a camera some years ago. Though, the IS is still very important to help you obtain nice images without worrying about the blurriness. Therefore, it is highly recommended that you should check the IS offering of your camera thoroughly before the purchase. If it possible, you should check the IS type in the list of your camera specifications as well.

What Is ISO In Camera Field

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Over the past few years, the number of manual settings that you can control over a digital camera has been increasing. This means that you can make adjustments to the auto settings for a certain scene to have images that are well focused and exposed.

You can even have at least several controlling options to adjust the most basic functions of taking photos in point-and-shoot cameras nowadays.

The ISO is one among these settings. However, it may not be as easy as you think.

In a digital model, the measurement of ISO sensitivity is the same as that of film speed in a 35mm film camera. When you see a higher number of ISO sensitivity, it means that it requires less light to produce the image. Consequently, the shutter speed becomes faster.

Essentially, the light sensitivity of the image sensor will increase when you set the ISO to a higher level. This is useful to produce nice photos when you shoot photos in low light conditions. However, when increasing the ISO, you may get more grainy photos or in another word, photos with noise. In this situation, there are a number of pixels which have not been correctly recorded by the image sensor of the camera.

However, when it is impossible to use the flash for low light circumstance or you’re shooting moving subject, the possibility to use the ISO is great. It can be better to have a photo under the average level than not to have any photo at all.

If finally you decide to use the ISO settings with your digital model, please read the following tips to find out more useful information about the way to adjust the ISO settings on your camera.

  • The common ISO range for a point and shoot model is often from 100 to 3200. And the ISO for high-end cameras, including both models using fixed lens and interchangeable lens is up to 12800 and even higher.
  • You’ll need to use the manual control or Program mode to be able to make adjustments on the ISOs. This is true for most digital models. It is pretty easy to adjust the ISO in most DSLR models, but it will require you to go through several menus on the screen to adjust the ISO.
  • The ISO range is often shown on the LCD together with other photography settings. If the ISO settings and other photography settings do not appear, you can press the Info button to figure out this situation.
  • If there is no Info button and you cannot figure out where the ISO setting is, it may require you to go through the menus of the camera to adjust the ISO settings.
  • With several DSLR cameras, it is possible to set an ISO number beyond the maximum and minimum ISO sensitivity settings by adjusting the EV settings. For instance, “Lo 0.3 EV” can lower the lowest ISO setting from ISO 200 to about ISO 160. An ISO setting of “Hi 0.7 EV” would raise the maximum ISO setting from about ISO 3200 to about ISO 5000. The particular ISO numbers with each camera’s EV settings is not completely identical, so make sure that you read your camera’s user guide carefully for the specifics.
  • Lastly, if the time of manually setting up the ISOs is more than you expect, the best way is to use shoot photos with an Auto ISO setting. The auto setting can be selected in the ISO sensitivity menu.

Camera Zoom Lenses

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Camera Zoom Lenses

Camera Zoom Lenses

Camera Zoom Lenses

 

Manufacturers tend to make certain specifications of a camera become more highlighted to help you easily make purchasing decisions. For example, they may emphasize on the large sizes of LCD screen or the high resolution.

However, you should not base on these numbers to evaluate the entire camera, especially the highlights about the zoom lens for a digital model. There are two types of the zoom lens – it is the digital zoom and optical zoom. Those types of zoom are much different from each, so you should have some thorough consideration. To tell you about those two types, only the optical zoom is persistently useful for photographers.

Commonly, you will see the zoom lens extending from the bodies of cameras. However, this is not always the case. For several digital models, it only requires you to make adjustments on the zoom lens within the camera body.  The information that I have mentioned in the following paragraphs will help you understand more about the zoom lenses and you yourself can make right conclusions about the digital and optical zoom lenses.

Optical Zoom

To understand what the Optical zoom is, you cannot help ignoring the term “focal length”. The focal length is measured from the image sensor to the center of the lens. And the actual increase of this focal length is measured by the Optical zoom. By extending the lens in a longer distance from the image sensor inside the body, you will see the increase of the zoom. That is because a smaller part of the scene hits the image sensor, leading to magnification.

There will be a smooth zoom when you are using the optical zoom. This means that it is possible to stop the zoom any time along the total length when you want to make any more specific zoom. The stops may be distinctive in several digital models during the length. The number of these stops is often between four and seven partial zoom positions.

Digital Zoom

Actually, the measurement of a digital zoom has not meaning for most photography situations. With the digital zoom, firstly, the photo is captured and then, the camera crops calculate the number of pixels to make for the zoomed photos. It is to artificially produce photos over short distances. With this type of zoom, the number of separate pixels will be magnified or removed, which can result in lowering the image quality.

The above function is similar to the way you use a software to edit your photos on your computer after taking the photo. If you find that it takes time to edit photos with the software, you will find the digital zoom very useful, in which you can shoot photos at the high resolution, then just removing a number of pixels and turn the resolution to the lower level, you can easily have pretty nice artificial photos over shot distances. Undoubtly, the digital zoom is useful in a limited number of situations.

Understanding Zoom Measurement

In the specification list of a digital model, you can see both the measurement of the two types in the format of an “X” character, for example, 5X or 10X. The magnification is higher for the larger numbers.

But don’t forget that all the measurement in the same specification like “5X” has the same meaning. The measurement is calculated from this extreme to that other of the lens abilities. Or you can understand that there is a “multiplier” or in another words, the difference between the maximum and minimum number of the focal length measurement. For instance, if the minimum measurement number of the focal length is 35 for an optical zoom lens measured 10X, the maximum number would be 350mm. However, if there are some extra wide-angle offerings in a digital model and its minimum focal length is 28m, the maximum one would be 280mm for an optical zoom measured 10X.

To avoid the confusion, the manufacturers should specify the focal length in a clear format in the specification list, for example, to “35mm film equivalent: 28mm-280mm.” Commonly, without magnification or shooting capacity at wide angles, the measurement of 50mm is a “normal” number. It will be very essential for you to compare the 35mm film equivalent number between this lens and the other lens if you are attempting to put the overall zoom range of a specific lens in comparison with other lens. You should look at the number on the right. Please make sure that you’re not confused about the zoom lens measurement.

Lenses which are interchangeable

Commonly, you’ll often see a zoom lens which is already built in the cameras that are targeted at photographers at the beginning and intermediate levels. However, Interchangeable lenses are more and more common for most digital SLR (DSLR) models. For a DSLR mode, if the zoom abilities and a wide angle are not offered as you want, additional lenses can be the good solution to have the larger zoom range and nicer wide-angle selections.

The price tag of DSLR models is higher than that of point-and-shoot models. The DSLR is often targeted at photographers at the intermediate or advanced levels.

There is not a “X” number to represent the measurement of the zoom lens in most DSLR lenses. And you will see the focal length right in the name of the DSLR lens. The focal length, not an X zoom number is also listed with the lens used in DIL (digital interchangeable lens) cameras, or also called mirrorless interchangeable lens cameras.

Some Zoom Lens Drawbacks

An optical zoom lens of the large size is nice and very useful in certain situations, which you often see in point and shoot models. But don’t forget some of small drawbacks.

  • The noise problem. When you maximize the focal length of a zoom lens, the image quality may be lowered. This is pretty common for budget-priced cameras aimed at the beginning level. The noise represents a collection of stray pixels which do not record accurately. You’ll often see edges in purple with this kind of photo.
  • The pincushioning problem.When you set the zoom to the maximum level, you may encounter the pincushioning problem, which is a distortion where you stretch the left and right edges of the image. You’ll see horizontal lines become a bit curved toward the frame center. This problem is more common for budget-priced models aimed at the beginning level with large zoom lenses.
  • The shuttering speed is slower. When a lenses is adjusted to the maximum zoom capability, the shuttering speed is often slower, which can result in blurry photos. Because of this drawback, you may not able to catch spontaneous photo. This slower shuttering speed is caused by the longer time that the camera needs to focus on the photos with the zoom setting at the maximum level. Especially in low light photography, the problem becomes even worse.
  • A tripod is required. Because of the zoom lens extended to the maximum level, the camera shake often appear. If there is the image stabilization feature with your camera, the problem can be correct. A tripod is a nice solution to help you avoid the image blurriness caused by camera shake.

Stay smart

Don’t be fooled by the highlighted specifications of the cameras. The measurement of the digital zoom and optical zoom can be combined because the manufacturers want to show a large number to attract your attention.

You should only take a look at the optical zoom measurement. This measurement number may be displayed in the back panel of the camera box together with numbers of other specifications. You also spend a little time figuring out the optical zoom measurement of a specific model.

To fully understand the zoom types can help you give the best decision. Be ready to thoroughly find out about the zoom capacity of a model before purchasing any camera.

 

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