ARDYADRIANA

Understanding White Balance

2009-05-22T21:55:00.000-07:00

UNDERSTANDING WHITE BALANCE

White balance (WB) is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photo. Proper camera white balance has to take into account the "color temperature" of a light source, which refers to the relative warmth or coolness of white light. Our eyes are very good at judging what is white under different light sources, however digital cameras often have great difficulty with auto white balance (AWB). An incorrect WB can create unsightly blue, orange, or even green color casts, which are unrealistic and particularly damaging to portraits. Performing WB in traditional film photography requires attaching a different cast-removing filter for each lighting condition, whereas with digital this is no longer required. Understanding digital white balance can help you avoid color casts created by your camera's AWB, thereby improving your photos under a wider range of lighting conditions.

BACKGROUND: COLOR TEMPERATURE

Color temperature describes the spectrum of light which is radiated from a "blackbody" with that surface temperature. A blackbody is an object which absorbs all incident light-- neither reflecting it nor allowing it to pass through. A rough analogue of blackbody radiation in our day to day experience might be in heating a metal or stone: these are said to become "red hot" when they attain one temperature, and then "white hot" for even higher temperatures. Similarly, blackbodies at different temperatures also have varying color temperatures of "white light." Despite its name, light which may appear white does not necessarily contain an even distribution of colors across the visible spectrum:

Note how 5000 K produces roughly neutral light, whereas 3000 K and 9000 K produce light spectrums which shift to contain more orange and blue wavelengths, respectively. As the color temperature rises, the color distribution becomes cooler. This may not seem intuitive, but results from the fact that shorter wavelengths contain light of higher energy.

Why is color temperature a useful description of light for photographers, if they never deal with true blackbodies? Fortunately, light sources such as daylight and tungsten bulbs closely mimic the distribution of light created by blackbodies, although others such as fluorescent and most commercial lighting depart from blackbodies significantly. Since photographers never use the term color temperature to refer to a true blackbody light source, the term is implied to be a "correlated color temperature" with a similarly colored blackbody. The following table is a rule-of-thumb guide to the correlated color temperature of some common light sources:

Color Temperature Light Source

1000-2000 K-------------Candlelight
2500-3500 K-------------Tungsten Bulb (household variety)
3000-4000 K-------------Sunrise/Sunset (clear sky)
4000-5000 K-------------Fluorescent Lamps
5000-5500 K-------------Electronic Flash
5000-6500 K-------------Daylight with Clear Sky (sun overhead)
6500-8000 K-------------Moderately Overcast Sky
9000-10000 K------------Shade or Heavily Overcast Sky

Since some light sources do not resemble blackbody radiators, white balance uses a second variable in addition to color temperature: the green-magenta shift. Adjusting the green-magenta shift is often unnecessary under ordinary daylight, however fluorescent and other artificial lighting may require significant green-magenta adjustments to the WB.

Auto White Balance

Fortunately, most digital cameras contain a variety of preset white balances, so you do not have to deal with color temperature and green-magenta shift during the critical shot. Commonly used symbols for each of these are listed to the left.

The first three white balances allow for a range of color temperatures. Auto white balance is available in all digital cameras and uses a best guess algorithm within a limited range-- usually between 3000/4000 K and 7000 K. Custom white balance allows you to take a picture of a known gray reference under the same lighting, and then set that as the white balance for future photos. With "Kelvin" you can set the color temperature over a broad range.

The remaining six white balances are listed in order of increasing color temperature, however many compact cameras do not include a shade white balance. Some cameras also include a "Fluorescent H" setting, which is designed to work in newer daylight-calibrated fluorescents.

The description and symbol for the above white balances are just rough estimates for the actual lighting they work best under. In fact, cloudy could be used in place of daylight depending on the time of day, elevation, or degree of haziness. In general, if you image appears too cool on your LCD screen preview (regardless of the setting), you can quickly increase the color temperature by selecting a symbol further down on the list above. If the image is still too cool (or warm if going the other direction), you can resort to manually entering a temperature in the Kelvin setting.

If all else fails and the image still does not have the correct WB after inspecting it on a computer afterwards, you can adjust the color balance to remove additional color casts. Alternatively, one could click on a colorless reference (see section on neutral references) with the "set gray point" dropper while using the "levels" tool in Photoshop. Either of these methods should be avoided since they can severely reduce the bit depth of your image.

IN PRACTICE: THE RAW FILE FORMAT

By far the best white balance solution is to photograph using the RAW file format (if your camera supports them), as these allow you to set the WB *after* the photo has been taken. RAW files also allow one to set the WB based on a broader range of color temperature and green-magenta shifts.

Performing a white balance with a raw file is quick and easy. You can either adjust the temperature and green-magenta sliders until color casts are removed, or you can simply click on a neutral reference within the image (see next section). Even if only one of your photos contains a neutral reference, you can click on it and then use the resulting WB settings for the remainder of your photos (assuming the same lighting).

CUSTOM WHITE BALANCE: CHOOSING A NEUTRAL REFERENCE

A neutral reference is often used for color-critical projects, or for situations where one anticipates auto white balance will encounter problems. Neutral references can either be parts of your scene (if you're lucky), or can be a portable item which you carry with you. Below is an example of a fortunate reference in an otherwise bluish twilight scene.

On the other hand, pre-made portable references are almost always more accurate since one can easily be tricked into thinking an object is neutral when it is not. Portable references can be expensive and specifically designed for photography, or may include less expensive household items. An ideal gray reference is one which reflects all colors in the spectrum equally, and can consistently do so under a broad range of color temperatures. An example of a pre-made gray reference is shown below:

Common household neutral references are the underside of a lid to a coffee or pringles container. These are both inexpensive and reasonably accurate, although custom-made photographic references are the best (such as the cards shown above). Custom-made devices can be used to measure either the incident or reflected color temperature of the illuminant. Most neutral references measure reflected light, whereas a device such as a white balance meter or an "ExpoDisc" can measure incident light (and can theoretically be more accurate).

Care should be taken when using a neutral reference with high image noise, since clicking on a seemingly gray region may actually select a colorful pixel caused by color noise:

Low Noise
(Smooth Colorless Gray)

High Noise
(Patches of Color)

If your software supports it, the best solution for white balancing with noisy images is to use the average of pixels with a noisy gray region as your reference. This can be either a 3x3 or 5x5 pixel average if using Adobe Photoshop.

NOTES ON AUTO WHITE BALANCE

Certain subjects create problems for a digital camera's auto white balance-- even under normal daylight conditions. One example is if the image already has an overabundance of warmth or coolness due to unique subject matter. The image below illustrates a situation where the subject is predominantly red, and so the camera mistakes this for a color cast induced by a warm light source. The camera then tries to compensate for this so that the average color of the image is closer to neutral, but in doing so it unknowingly creates a bluish color cast on the stones. Some digital cameras are more susceptible to this than others.

Automatic White Balance
Custom White Balance
(Custom white balance uses an 18% gray card as a neutral reference.)

A digital camera's auto white balance is often more effective when the photo contains at least one white or bright colorless element. Of course, do not try to change your composition to include a colorless object, but just be aware that its absence may cause problems with the auto white balance. Without the white boat in the image below, the camera's auto white balance mistakenly created an image with a slightly warmer color temperature.

IN MIXED LIGHTING

Multiple illuminants with different color temperatures can further complicate performing a white balance. Some lighting situations may not even have a truly "correct" white balance, and will depend upon where color accuracy is most important.

White Balance Example: Mixed Lighting

Under mixed lighting, auto white balance usually calculates an average color temperature for the entire scene, and then uses this as the white balance. This approach is usually acceptable, however auto white balance tends to exaggerate the difference in color temperature for each light source, as compared with what we perceive with our eyes.

Exaggerated differences in color temperature are often most apparent with mixed indoor and natural lighting. Critical images may even require a different white balance for each lighting region. On the other hand, some may prefer to leave the color temperatures as is.

Note how the building to the left is quite warm, whereas the sky is somewhat cool. This is because the white balance was set based on the moonlight-- bringing out the warm color temperature of the artificial lighting below. White balancing based on the natural light often yields a more realistic photograph. Choose "stone" as the white balance reference and see how the sky becomes unrealistically blue.

Souce from: www.cambridgeincolour.com . For self guide.

Lense Tutorial, Understanding Camera Lenses

2009-05-06T21:39:00.000-07:00

Lense Tutorial, Understanding Camera Lenses

While looking for lenses to buy for a digital camera, I’ve realized that there are many things about lenses that I didn’t know about and are important in determining the overall performance of a particular lens.

For example: Canon EF-S 60mm f/2.8 USM macro

Except macro and 60mm f2.8, the rest of the info should be researched in order to understand what “EF-S + USM” mean, especially on a digital camera.

CANON lenses notations:

* EF - The EF lens mount allows all the Canon EF lenses to be used on any of the Canon EOS. EF stands for “Electro-Focus”: automatic focusing on EF lenses is handled by a dedicated electric motor built into the lens. All communication between camera and lens takes place through electrical contacts; there are no mechanical levers or plungers.
* USM - Ultrasonic motor drive - EF lenses equipped with USM drives have fast, silent and precise auto focus operations, and consume less power compared to other AF drive motors. There are two types of USMs, the ring-type USM and the micromotor USM. Ring-type USM is always preferred because of its superior performance and efficiency, and it allows for full-time manual focus operations without switching out of AF mode.
* IS - Image stabilizer - the Image Stabilizer (IS) counters camera movements and shakes by optically correcting such shakes with accelerometers and lens groups that move in relation to the shakes, thus minimizing or even eliminating minute vibrations from the image. A general rule-of-thumb to overcome such vibrations would be to set the shutter speed equal to or faster than the reciprocal of the lens focal length (e.g. 1/125s for a 100 mm lens). IS lenses can improve on this rule by up to three stops. That is, the same 100 mm lens could be used at 1/30s.
* L - series lenses - top of the line Canon EF lenses are designated as L-series. L-series lenses have superior optical performance and are typically built with a solid construction to withstand constant use and harsh conditions. They can be recognized by a red ring around the front part of the lens. Most recent L lenses have sealing to help resist dust and water. L-series lenses are more frequently used by professionals and serious amateurs due to their high price and large mass.
* EF-S - The lens mount is a derivative of the EF lens mount created for a subset of Canon digital single-lens reflex cameras with APS-C sized image sensors.

NIKON lenses notations:

* Nikon F-mount refers to a lens mount developed by Nikon for its 35 mm SLR cameras
* AF - auto focus designation, indicating focus driven by a motor inside the camera body.
* AF-S - Auto focus-Silent. Uses a “Silent Wave Motor” (ultrasonic motor) to focus quietly and quickly. Similar to Canon’s “USM” technology
* AF-I - Auto focus-Internal - driven by a coreless DC motor.
* ED - “Extra-low Dispersion” glass incorporated to reduce chromatic aberration. “Super ED” glass has been introduced as well.
* IF - Internal Focus - focusing is accomplished through the movement of internal lens groups, eliminating extension and rotation of the front lens element.
* DX - Lens designed for Nikon DX format sensors. The image circle matches the smaller sensor area of Nikon’s digital SLRs. A vignetted image may be produced if used on a 35mm format camera, although some DX lenses cover the full 35mm frame at longer focal lengths.
* VR - Vibration Reduction - uses a moving optical group to reduce the photographic effects of camera shake. Similar to Canon’s Image Stabilizer, Sigma’s OS
* D - Distance/Dimension - indicated after the f-number number. It means the lens is capable of using Nikon’s 3D Matrix Metering on bodies that support it. The lens transmits focus distance information, which is incorporated into the camera’s exposure calculations.
* G - Indicated after the f-number. G lenses do not have an aperture ring, and the aperture can only be controlled electronically by the camera body
* GN - Guide Number - aides in making flash exposures on cameras without automatic flash metering.
* Micro - Micro lenses are capable of high reproduction ratios for macro photography.
* N - Indicates the Nano Crystal Coat, a new type of lens coating that originated in Nikon’s semiconductor division.
* PC - Perspective Control - lens includes movements to control perspective and depth-of-field.

SIGMA lenses notations:

* APO - Apochromatic lens element(s)
* OS - In lens “Optical Stabilization”, analogous to Nikon VR or Canon IS
* HSM - “HyperSonic Motor”, in-lens ultrasonic motor, analogous to Nikon AF-S or Canon USM
* EX - “Excellence”, professional series.
* DG - Coatings optimized for Digital SLRs, still usable on 35mm or full frame
* DC - Lenses for DSLRs featuring APS-C size sensors only
* DF - “Dual Focus”, lens features clutch to disengage focus ring when in AF mode
* HF - “Helical Focusing”, front element of lens does not rotate (for when using circular polarizing filters)

TAMRON lenses notations:

* Di — “Digitally Integrated”, featuring coating optimized for digital SLRs, but still usable on 35mm or full frame
* Di II — Lenses for DSLRs with APS-C sized sensors only
* SP — “Super Performance”, professional lenses
* IF — “Internal Focus”
* LD — “Low Dispersion” elements
* XR — Extra Refractive Index glass
* VC — “Vibration Compensation”, in lens stabilization analogous to Nikon VR or Canon IS

TOKINA lenses notations:

* AT-X - “Advanced Technology-Extra” - lenses that are manufactured without compromise, using the most advanced design and fabrication technologies available
* F&R - the largest aspherical elements being employed in optical designs today. These give outstanding performance with very even illumination in the corners and correction of spherical aberration
* SD - Super Low Dispersion - to eliminate chromatic aberration, Tokina uses special glass material having super - low dispersion (SD) properties.
* HLD - High-refraction, Low Dispersion. Having higher refractive index and lower dispersion properties, HLD glass is far less likely than standard optical glass to create lateral chromatic aberration.
* Multi-Coating - Reflections off the surface of lens elements are reduced or eliminated by bonding multiple layers of a transparent anti-reflection chemical to the surface of the glass
* Floating Element System – many Tokina lenses employ floating element systems to provide optimum correction of astigmatism from minimum focus distance to infinity.
* IFS - Internal Focus System - The internal focusing system used by Tokina move each element group within the lens, but does not change the overall length of the lens.
* Focus Clutch Mechanism - Tokina AT-X PRO series lenses all feature the patented “Focus Clutch” Mechanism for switching the lens between auto focus and manual focus modes.

References:
www.canon.com
www.nikon.com
www.tokinalens.com
www.tamron.com
www.sigmaphoto.com

Source From: www.digital-cameras-help.com

Basic Photography For Beginner

2009-05-06T20:06:00.000-07:00

..Sometimes we think that we are good in this areas. but..are you really that good? but if you that good, your name will be top of the world now.. but then are you really that good or you just good in taking picture but leak of basic photography.

..for me.. i know that i'm not good in this photography because i just started.. explore new knowledge and experience. but sometimes, a professional (they called themselves) or experience photographer also just know how to shoot and edited photo but than if we talk about basic photography, do you think they know?

..either you are professional or beginner, the first rule that i'd learned is.. know your basic.. basic of photography..

..for this.. i want to ask you something.. what is your level of understanding the world of photography.. do you know well you camera or system and mastered it..

.. just for sharing.. i got this from http://www.digital-cameras-help.com, hope this will help us know well your knowledge..:)..

Basic Photography Tips

There are three technical elements that "make" an image

* Aperture
* Shutter speed
* ISO speed (sensitivity of the digital sensor)

1. Aperture

The aperture determines the amount of light that gets to the digital sensor. A SMALL number indicates a LARGE aperture, good lenses start with a maximum aperture of 2, better and more expensive lenses start at 1.1!

Apart from the quantity of light that is allowed to get through, the aperture also determines the DOF (depth of field).

The numbers you see on the side of a lens usually look like this:

F 22 | 16 | 11 | 8 | 5.6 | 4 | 2.4

At F 22, the lens lets in a very small amount of light, it is at minimum aperture. At F 2.4, the lens lets in the maximum amount of light that it has been designed for.

Each number represents a double increase (or decrease) of the quantity of light that is allowed through the lens.

For example: at aperture 5.6 you allow 2 times more light than at aperture 8, and 2 times less light than at aperture 4

On "point and shoot" digital cameras you do not see this numbers on the side of the lens, the process of opening and closing the aperture is controlled electronically and has also increments like: 5.9 or 8.2

2. Shutter Speed

The shutter is the device that controls the exposure time of the photo. The exposure time usually begins at 1/2000 sec. and goes up to 30 sec.

At 1/250 sec. exposure time, the shutter will let in 2 times more light than at 1/500 sec. and 2 times less than at 1/125 sec.

The exposure time determines how a photo will look, if it will be "shaken" or crystal clear. For example: you want to take a picture of a water fountain. You have two options, use a short exposure, or a long one. A short exposure (of 1/2000 sec.) will "freeze" the water droplets in mid air; the detail of every droplet will be clearly visible in the photo. A long exposure time (of 1 sec.) will create a special effect where the falling droplets traces unite to create streams of water.

3. ISO Speed

ISO speed is the third element that "makes" a photo. It is usually expressed with the following numbers:

50 | 100 | 200 | 400 | 800 | 1600 | 3200

These numbers tell you how "fast" does the digital sensor react to the light sent through the aperture and shutter.

A small number means that it takes a relatively long time to take a photo, a large number, a very short time.

But things are relative in using the right ISO setting. On an average digital camera, the ISO goes from 50 to 400. The ISO speed 50 is usually used on bright sunny days, while the 200 and 400 ISO is used in low light conditions (like interiors or at night)

There is also a problem with the image quality regarding the ISO speed. At large numbers, 400, 800, the image will contain "noise", so use the low ISO speed as much as possible.

Here is a table that will further explain how the aperture, shutter speed and ISO speed are used TOGHETHER to "make" an image. I'll give a theoretical example of how this three indicators work together: At ISO speed 100 you select an aperture of 8 and the shutter speed is calculated by the camera at 1/250 sec. The same image*, mathematically speaking, can be created using the following settings:

ISO speed Aperture Shutter speed

100 16 1/60
100 11 1/125
100 8 1/250
100 5.6 1/500
100 4 1/1000

As you can see, with the ISO speed constant, the aperture and exposure time increase or decrease in connection with each other; if the aperture allows more light into the camera, the shutter speed decreases to compensate and give the perfect exposure.

But what happens to these theoretical numbers if you set the ISO speed at 50? Take a look:

ISO speed Aperture Shutter speed

50 11 1/60
50 8 1/125
50 5.6 1/250
50 4 1/500
50 2.8 1/1000

You can modify the aperture, keeping the shutter speed constant, or you can modify the shutter speed, while keeping the aperture values constant:

ISO speed Aperture Shutter speed

50 16 1/125
50 11 1/250
50 8 1/500
50 5.6 1/1000
50 4 1/1250

Aperture Priority Mode

It is a setting on most digital cameras that allows the user to choose the aperture, while the camera calculates the shutter speed for a good exposure.

The need for using this shooting mode arises from the need to control the depth of field (how much of the image will be in focus); the larger the aperture, the shallow the depth of field.

This mode is useful when you need to separate the subject from its background. If you want to make a portrait of someone, with trees in the background, a large aperture of 2 or 3 will be the one to use. If you use a smaller aperture, like 8 or 16, the trees and the subject are all going to be clear and in focus. This way, you might obtain the strange image of a branch sticking out of your friend's head!

However, using a small aperture is very useful in dealing with landscape photography. In this case, you usually create an image of a large space and showing every detail of the landscape becomes paramount. In this case, using a small aperture will give you a full clear image.

Shutter Priority Mode

This shooting mode is very useful when dealing with the problem of a moving subject. For example, a car traveling at a speed of 50 km/h is doing about 13.8 m/sec. So, if you use a shutter speed of 1 sec, you will obtain an image with background, but no subject!

At this shutter speed (1 sec.) the car has moved almost 14 m; in the best case you might get a trail of the shadow of the car� What you need to do is to freeze the action. To "make" the car appear to be still, you'll have to use a shutter speed of 1/2000 sec. Even at this shutter speed, the car has moved about 7 mm... not a very clear picture. So, if your camera allows it, you'll have to push the limits of the shutter to 1/4000 sec.! Also you can move your camera, tracking the car. In this situation, the car appear to be standing still, while the background will be blured.

However, the shutter can also be set for a long exposure time. This allows for the very useful effects, particularly useful for night photography. These long exposures always require the use of a tripod to steady the camera.

Zoom

This feature is probably the most talked about property of a digital camera. From the 10x, 12x, 4x lenses to more traditional language like the "35 mm equivalent", the zoom of a particular lens is a subject of a lot of confusion.

To put things in order, let's start with the 10x, 4x expression of zoom. First of all, it appears to be a very good standard. A camera with 10x zoom can be seen as a far better one than a 4x. I mean, 10 is a larger number than 4; but there is a problem�

10x what?, 4x what?

This is the big problem with this system, you have no reference point. It simply tells you that a 10x zoom will give you a 10 x magnification of the image that you get at 1x zoom.

But how large is the field of view at 1x? Big question! You practically cannot compare two digital cameras this way because of the lack of a reference point.

So, how about the "35mm equivalent" system? Well, with this system, things get very tricky if explained properly. It involves a lot of technical things but I believe that you need a clear, simple answer!

The explanation starts with the understanding of the field of view. On lenses specifications you'll find something like 35-140 mm equivalent zoom. At 35 mm equivalent, on this particular lens, you get the largest field of view, you can put a lot of scenery in a photo. At 140 mm equivalent, the field of view shrinks by a factor of 4.

To simplify the problem, you will need to take a look at your feet:

Landscape Photography

It is the most common form of photography. All you need to do is to be surrounded by beautiful scenery, point your camera in a particular direction and take a picture!

But there are also some things you need to know before taking a picture. It would be very simple to set your digital camera on a full automatic landscape mode, but there is a better way.

You have to check your surroundings, particularly for wind conditions. The wind can cause the movement of flowers and tree branches. It may feel good to be in the middle of nature, cooled down by a gentle breeze, but that is not a very good thing for your photos.

Generally, with a landscape photo, you will probably try to "get in" as much as possible. To do this you need a full clear picture, which can be obtained using a small aperture (smaller than 8). However, a small aperture also means a long exposure time, in the case of a windy day, the picture will be ruined by small but visible movements of your "scenery".

There are two ways of taking a good landscape photo: use the aperture priority mode, or the shutter priority mode. In the case of a clear day with no wind, set your camera to a small aperture, in windy conditions, select the shutter priority mode, with exposure time of less than 1/400 to "freeze" any movement.

Night Photography

It is a particular form of photography, which requires good technical knowledge of the capabilities of a digital camera and a tripod. The challenges arise from the absence of light.

The poorly light scenery can be captured as an image only with long exposure times. This type of photography requires good knowledge of what is ISO speed and how steady is a camera at different shutter speeds.

Take a look at the image below:

Shutter Priority | Shutter Speed 1/13 | Aperture Value 2.5 | ISO Speed 50

As you see, there are some indicators to help you with your images:

* Shutter Priority - the camera is set on shutter priority mode because the most important setting you need to control during night photography is the exposure time
* Shutter Speed 1/13 - at 1/13 sec. the shutter speed is very slow. On various occasions, you may even get to 1, 5 or 10 sec. exposure time.
* Aperture Value 2.5 - at F 2.5, the aperture is at the maximum I had available for my digital camera
* ISO Speed 50 - I've used this ISO setting because of the low noise it generates. Remember the fact that for higher ISO values you get more and more noise. You get a lot of noise even if you are at ISO 50 using very long exposure times, like 5 or 10 sec.

Macro Photography

The photos that can be included in this category are those that depict reality at a 1:1 scale. So, if you take the picture of a butterfly and it has a wing span of 3 cm, the printed image must have a butterfly with a wing span of at least 3 cm.

For DSLR cameras, there are specialized very expensive macro lenses, witch provide extreme magnification and image detail. However, most digital cameras have a zoom lens, with built in macro capabilities.

What you must understand about macro photography is the fact it can be very satisfying. The amount of detail that can be captured with even a modest, low cost digital camera is breathtaking. In dealing with macro photography, you need patience and luck.

First, you need patience in setting the camera; because you have a very shallow depth of field, the camera must be very still, or the image will be out of focus. Luck is required when dealing with subjects like insects. They tend to move...

Aperture

Aperture is a device that controls the quantity of light that passes through the lens. It is an iris type mechanism, which shrinks or grows in order to let in less or more light.

The numbers you usually see on a lens are:

Each number lets in two times less light than the previous one.

Small numbers represent a large aperture, big numbers - small aperture. Most digital cameras do not have this numbers written on their lenses, but they use aperture as part of their construction. It is also the way for you to select aperture priority shooting mode from your camera to control the depth of field.

Shutter Speed

The shutter is a mechanism that controls the exposure time of an image. This time can be manually set by using the shutter priority shooting mode from your digital camera. The numbers you'll use will look probably like this:

15, 13, 10, 8, 6, 5, 4, 3.2, 2.5, 2, 1.6, 1.3, 1, 0.8, 0.6, 0.5, 0.4, 0.3, 1/4, 1/5, 1/6, 1/8, 1/10, 1/13, 1/15, 1/20, 1/25, 1/30, 1/40, 1/50, 1/60, 1/80, 1/100, 1/125, 1/160, 1/200, 1/250, 1/320, 1/400, 1/500, 1/640, 1/800, 1/1000, 1/1250, 1/1600, 1/2000 sec.

These numbers represent how long the light will be allowed to hit the digital sensor in order to capture the image.

ISO Speed

ISO speed shows how sensitive the image sensor is to the amount of light present. The higher the ISO, the more sensitive is the image sensor.

The ISO is represented by numbers:

ISO 50 | 100 | 200 | 400 | 800 | 1600 | 3200

Each number represents two times the sensitivity than the previous one. Higher ISO settings are very useful in low light situations, but the disadvantage of noise appears. The higher the ISO, the higher the noise levels you get.

Image resolution

Is the most talked about feature of a digital camera. From 3 to 12 megapixels or more, it seems that with every generation of digital camera there is an increase in image resolution.

But what is a megapixel? Well, a megapixel is represented by 1000000 pixels.

So, if the maximum resolution of a digital camera, results in an image 3000 pixels in width and 2300 pixels in height, that camera would be a 3000 x 2300 = 6900000 / 1000000 = 6.9 MEGAPIXELS

When talking about megapixels, there is the question: how much do you need? Especially because the more a camera is capable, the more expensive it is.

If you are going to use the images on the Internet, you may find that the maximum resolution of 1600 x 1200 might be enough. That would lead you to buy a 1.92 MPx camera!

If you want to print an image, you need to consider the dpi requirements. 300 dots per inch is a standard in printing any image. It simply means that all you have to do to find out the maximum width of a printed image is to divide its width in pixels by 300.

3000 pixels / 300 = 10 inches maximum.

Image Stabilization

Image Stabilization is also known as vibration reduction and anti-shake; it is a technology found on digital cameras with long telephoto zooms (10X and 12X). It helps prevent images from becoming blurred.

This technology helps people in taking photos that require slow shutter speeds. The system works in two different modes. There are systems that stabilize the shot by moving the image sensor or by moving optical elements inside the lens.

This anti-shake system can make the use of a tripod redundant, but there are situations when at very slow shutter speeds (>1 sec.) the image stabilization cannot cope with the movement of a hand held camera.

Image Format

Digital cameras store the images they produce in two different formats: JPEG and RAW. JPEG is the most common used image format, while RAW is usually used by professionals.

The differences between the two go beyond the image size. A JPEG image is a compressed image, for example, an 8 MB RAW image can be compressed to a 3 MB full quality JPEG.

The RAW format produces much more that a BIG image. It also has been described as a "digital negative". Professional photographers use RAW because they can make later modification to the image that wouldn't be possible using JPEG.

The disadvantage is the fact that you need specialized expensive software to read and modify RAW format images. You also need time and patience. Let's say that you make 100 photos in RAW format and 100 photos in JPEG.

The JPEG images are ready to use, you may discard 20 of them because of bad exposure, but you have the rest of the images ready to be printed or to be published on the Internet.

With RAW images, you'll need at least 1-2 hours of opening the 100 images with photo editing software and tweak their properties to the point when you'll get the image you want.

Focal Length

The focal length of a digital camera lens is the distance between the center of the lens and the image sensor when an in-focus image is formed. The focal length of a digital camera lens is displayed on the barrel of the lens along with the measurement of the largest aperture and the maker.

The focal length of a lens establishes the field of view of the camera. The shorter the focal length is, the larger the field of view.

Camera lenses are categorized into normal, telephoto, and wide angle, according to focal length. Thus a 200 mm equivalent telephoto lens gives a 4 x magnification over the 50 mm equivalent lens.

Depth of Field

Depth of field is the amount of distance between the nearest and farthest objects that appear in focus in a photograph. In simpler term, we define depth of field as the zone of sharpest focus in front of, behind, and around the subject on which, when lens is focused on a specific subject.

There are three key factors that have a direct relationship with depth of field:
Aperture
Focal length of the lens
Subject size

The general rule for selecting the right aperture for a desired depth of field is: given the same distance to the subject and subject size, the bigger lens opening (aperture) used (like f/2.8, f/2, f/1.4 etc.) will have a narrower band of depth of field.

Depth of field increases with distance. The farther you place the camera from your subject, the more depth of field you can obtain. Landscapes have great depth of field, while macro photographs tend to have very little depth of field because the subject is so close to the lens.

White Balance

The white balance setting for a digital camera is very useful in dealing with various light conditions. The best way to understand this setting is to place a white sheet of paper in front of your camera and take a photograph.

If the image has a white sheet of paper in it, you're ok; but if the paper has a yellowish hue, you're in trouble.

To better understand this process, take a look at your lamp. It usually uses an incandescent bulb. If you look closely, you'll notice that the color of this particular source of light has a yellow hue. The digital camera amplifies this hue and you get a yellowish photograph.

So, before taking any photo, look around at your sources of light. Even if you are outdoors, there are white balance settings that will make your photo look a lot better.

* Daylight white balance
* Cloudy white balance
* Tungsten white balance
* Fluorescent white balance
* Flash white balance

Exposure Compensation

Exposure Compensation is a feature on a digital camera that allows you to adjust the shutter speed measured by its light meter. Usually, the range of adjustment goes from +2 to -2 EV in 1/3 steps.

Lets say that you point the camera at you subject and the meter says you need 1/250 sec. shutter speed at aperture 5.

If for whatever reason you select +1 exposure compensation, the shutter speed used by the camera will be 1/125 sec.

If you use -1 exposure compensation, the shutter speed will be 1/500 sec.

Every increment in exposure compensation (+2 | +1 | -1 | -2) increases or decreases the amount of light going through the camera by a factor of 2.

Batteries

When buying a digital camera always look at the type of batteries it is using. Some have large LCD screens, these consume a lot. Using the flash also cuts in half the time you are using the camera. If possible, buy a camera that has specially designed rechargeable batteries. These come with their own charger and last a lot more than if you were to use normal AAA rechargeable batteries.

NiCad Batteries

NiCad (nickel cadmium) batteries offer a relatively long life, high discharge rate and economical pricing, but they have distinct disadvantages as well. NiCad batteries must be completely discharged before they are charged or their performance per charge is diminished. You can expect around 700 or more recharge cycles depending on usage; you should periodically cycle these batteries through a complete discharge. Be aware that toward the end of their supply, they go from good power to zero power rather abruptly.

Lithium-Ion Batteries

Li-ion(lithium ion) batteries have long shelf life but in AA, AAA forms they are not rechargeable. These non-rechargeable lithium batteries do last from one and a half to 2 times longer than NiMH batteries; Lithium-ion (or lithium) is not environmentally friendly and requires special disposal.

NiMH Batteries

NiMH (nickel metal hydride) batteries are the battery of choice for high drain applications (digital cameras). They have a long life and can last from 500-1000 charge cycles. Per charge cycle, NiMH will run one and and one half to two times longer than alkaline. They are more robust and can be recharged at any point in the discharge cycle. Nickel metal hydride is environmentally friendly, requires no special disposal procedures and contains no toxic metals. Moreover, they are much less toxic during the recycling process. NiMH batteries are fairly expensive. They also lose their charge faster than other types, if stored for more than a week, should be recharged before use.

Photographic filters

Photographic filters have been in use for a long time. They were required for special effects or to enhance the contrast of some colors. They were also used for white balance.

For example, a film set for daylight color temperature, would have produced yellowish photos when taken inside, with incandescent light bulbs lighting the scene. To compensate, a blue filter had to be used, to get the right colors.

The major advantage of digital cameras is the fact that you can adjust the white balance of a scene electronically, without the use of a color filter. As far as the image effects that could be obtained with some filters (like blurring the image, changing color hue for specific areas of a photograph, etc.) there are better ways of getting them onto a photo.

Very cheap image software can produce more effects on a photograph than all the filters in the world combined. With a little bit of imagination, using software to get the effects you want is the best way to go.
The only filter a digital camera actually needs is a polarizer.

Polarizers come in two varieties:
Linear polarizers
Circular polarizers

Each has the same effect but circular polarizers are more expensive. Digital cameras can use both (linear and circular) polarizers.

Polarizers produce deeper colored blue skies, minimize light reflections from glass and water and reduces glare from non-metallic surfaces. They also provide good color saturation. Can be used in extremely bright light situations to reduce the amount of light entering the camera; this enables more selective depth of field control.

Copyright © 2007 www.digital-cameras-help.com

Lighting Effect

2009-03-31T06:51:00.000-07:00

..aku gunakan gambar kawan ku ini untuk percubaan.. teknik Strobist menggunakan Nikon yang menjadi teman seiringan baruku..

Photo ini sengaja dibuat sedemikian untuk menampakkan wajahnya yang seolah-olah menakutkan. Untuk latihan lain, akan saya upload kemudian..

Still Object

2009-03-31T06:47:00.001-07:00

Still Object.. istilah yang simple untuk jurugambar.. ambik gambar yang "tak bergerak" dan ciptakan sesuatu yang kreatif darinya.. macam yang teknik yang aku gunakan adalah Strobist..

Orang KL yang sporting

2009-03-31T06:38:00.000-07:00

.. Tengah aku makan-makan bersama teman, gadis ayu ini merelakan dirinya dipotretkan dan diabadikan di dalam cameraku.. ku capai camera (bergegar jantung sebab tak diduga merelakan digambar walaupun tak kenal).. terus ku "snapped".. terima kasih orang KL.. yang aku sendiri pun tak tahu namanya.. :)..

Street Photographer

2009-03-31T06:31:00.000-07:00

..KL.. Bukit Bintang is the most popular place to visit. People around the world gathered here.. shopping here.. massage here (foot ler).. and "cari makan here" for what.. to SURVIVE.. A city that can't promise you happiness but can give you all the pleasure you want, that if you can survive in this "jungle of rocks"..

2009-03-21T18:02:00.000-07:00

BASIC DIGITAL CAMERA SHOOTING TECHNIQUES

Basic Composition: Getting it right

Keep the composition simple!

Start by shooting on the level. With experience, you can learn to shoot at an angle to add dramatic impact to the shot.

Always keep your eye on what’s happening at the front and the back of the frame and NOT just on the immediate subject.

If the background is 'messy' (like my office), move the subject against a plainer-looking background. If this is not possible, use the zoom lens to frame distractions out of the shot.

Note: If zoomed in, you might have to step back to keep the subject in the frame

Keep your composition simple

Avoid telephone poles, wires, cables, litter and street rubbish. Use the zoom lens or physically move yourself to frame these ugly distractions out of shot. Avoid taking pictures in bright sunshine. Always move your subject into the shade where they’ll be relaxed. So will you!

Make an effort to pose your subject, otherwise you’ll end up with the typical 'school photo' result; staring straight into the lens and grinning like a prison inmate!

Candids, those shots we all love to take without actually talking or looking properly at the subject, almost always never work!

Clean Background

Here’s a tip: Always, always shoot with an uncluttered background so that you look at the subject, and not at the telephone pole or McDonald’s sign that’s sticking out of the top of their heads!

Choosing the Right Shooting Mode

Most pictures will come out fine with the camera set to 'P' or Program Mode rather than the Auto everything mode.

For portraits, use the Portrait Mode (this helps make the background go a bit out of focus) or set the camera to Aperture Priority mode (called ‘A’ or ‘Av’) and manually choose a setting of about f4 or f5.6. This keeps things sharp on the subject, but reasonably fuzzy everywhere else.

Take care what you focus on!

For landscapes, or far-off subjects, use Landscape (or 'Mountain') mode. This locks focus into the distance and guarantees a sharper-looking distant shot.

For all action shots, use the simple Sports Action mode, or for greater user control, Shutter Priority mode (called ‘T’ or ‘Tv’). Pick a shutter speed of about 1/500s to 'freeze' the action.

(Note: if you use these 'fast' shutter speeds, you might run out of llight! If this is the case, choose an ISO sensitivity setting of 200 or 400 if there’s not much light).

Avoid Shooting on Full Auto Mode

Don’t shoot on Auto. This is an ‘idiot-proof’ shooting mode. None of you are idiots!

First, switch to the ‘P’ or Program Auto setting. This is also an automatic shooting mode, BUT in this mode you can override its behaviour in order to make the resulting pictures look even better (ie. lighter, darker, more contrasty, etc).

Use the optical viewfinder for normal shooting. It will give you a better idea of what you are getting in the shot because you’ll not be put off by reflections, bright sun or falling off the pavement while struggling to get the viewing angle right.

Tip: Using the LCD for composing is not the best way - it's not stable and is prone to camera shake. Hold the camera to your face and use the optical viewfinder.

Tip: When travelling, use the LCD screen only for close-ups (in the Macro mode) and for reviewing once back in the hotel. Excessive use reduces battery life significantly.

Snapping Portraits

Set the controls to Portrait Mode if the camera has one. This ensures that, although the subject of the portrait remains clear, its immediate background and foreground becomes fuzzy. The idea is to 'isolate' the subject using sharpness.

For greater control over this fore- and background sharpness, set the camera to 'Aperture Priority', (usually denoted by an ‘A’ or an ‘Av’ icon).

This setting is usually located on the main command dial on the top of the camera. Dial in an aperture of f5.6 (or thereabouts) using the thumbwheel. This f-stop number gives a reasonable depth of focus so that the figure that’s focused on is sharp (clear) but the background will be of focus (blurry).

The lower this f-stop number is, the less you get in focus in the shot and the more careful you have to be when focusing! Note: Setting the camera to Portrait Mode does this for you without your having to think about it ...

Stuff to remember:

Don’t go too close, it can be intimidating. Step back and zoom in with the lens zoom lever.

Never use the wide angle lens setting on the zoom for single people shots. It produces very unflattering results. (It’s OK for groups though).

Avoid using flash on the face, it can be very unflattering.

In fact, NEVER use flash in a portrait if it can be helped.

Landscape Mode

To make sure that your distant scenes (landscapes, cityscapes) look their best, set the focus button to 'Mountain Mode' or 'infinity' (the infinity symbol looks like the figure eight (‘oo’) lying on its side).

Do this either in the menu, or by pressing the mountain symbol button or the MF button. This should give you failsafe sharpness for all distant objects (especially when shooting at night because the camera can’t see), and in low light.

Remember, cameras have difficulty focusing on far away scenes and in low light.

You could also try setting the camera to Landscape Scene Mode, if there is one.

Use the wide angle setting ('W') on the zoom lens to get more of the scene in.

More Stuff to Remember

Avoid shooting through glass (i.e. don’t be lazy, get out of the car!)

Don’t shoot within three hours of midday if it can be avoided (Early morning and late afternoon are the best times). The examples you see here were taken at 11am (way too bright) and again at 6:30 pm, one of the best times of the day for landscape photography.

by Robin Nichols | betterphoto.com

2009-03-21T17:48:00.000-07:00

..Asean main food. Can't imagine what will happen without it. Price for it will increase, and will suffer all of mankind. So respect it and take care of it because it is a gold of our live..

The Beautiful Of Nature

2009-03-19T06:31:00.000-07:00

.. Nature is the beautiful things ever for us to share.. Feel it.. share it before it all be gone forever..