How Does a Camera Lens Work?

A camera lens which is also known as photographic lens is a series of curved glasses that bring the rays of lights together to form an image. The small optical glass lenses are placed at different lengths from each other.

As a photographer turns the ring located on the barrel of lenses, the pieces of glasses inside the camera moves closer or further away from each other.

A camera lens projects a circular image. However, the sensor captures a relatively small rectangular area at the center of this projected view.

If the rectangle is extended to the edge of this circle, the sensor should be able to capture the full field of view. Conversely, if the rectangle falls short of this, the field of view is then reduced. Most difital cameras use the conventional 35mm format lenses which results to reduced field of view available to the sensor. However, for wider views, a wide-angle converter will be helpful.

Some digital cameras feature zoom lenses with very large ranges where focal length reaches as much as 420mm. And to reduce unsharpness caused by camera shake, an optical image stabilizer is much helpful.

55 mm

                                                                 

105 mm

                                                                  

135 mm

              

                                                                   

200 mm

                                                                  

                   These images are taken at the same distance from the object using different focal lengths. Notice how the background gets blurry as the focal length increases? That's because wider lenses tend to magnify distance between objects and allow greater depth of field. Longer lenses magnify the subject more by compressing the distance which results to blurry background as the depth of field gets shallow.

Basic Kinds of Lenses

Normal Lens has focal ranges that are similar to a human eye. 35 to 50mm lenses are considered normal lenses.

Telephoto Lens is the longest and heaviest among the lenses. The subject appears very close but the range of view will be very narrow.

Wide Angle Lens as the name implies has a short but wider views than a typical standard lens of the same focal length. Think of the field of view as captured by a fish where the term fisheye lens is derived. Lenses with focal lengths of 8 to 16mm are considered as fisheye lenses.

Using Wide Angle Lens

How Digital Camera Works as Explained Simply

If you are a beginner in photography, understanding how digital camera works will help you comprehend the basics, and how each of the basic parts relate to each other which will eventually lead to better pictures.

Basically, a digital camera works much the same way as the human eye. The illustration above shows how the light travels from the object until it reaches the sensor.

The rays of lights travel thru the lens first. Lenses are series of curved glasses that bring the light together to form an image.

Then it goes through the aperture which is placed inside the lens. An aperture is an opening that controls how much light reaches the sensor. You can think of aperture as a window.

The shutter, on the other hand, is like a curtain. It controls the length of time that the light fills the room. A shutter is located in front of the sensor.

A sensor is a sensitive plate where light that travels thru the lens, and controlled by the aperture and shutter, is absorbed and transformed into pixels.

Once an image is processed, digital cameras store the digital representation of a subject onto a memory card where images are ready to be downloaded into a computer as digital files.

Now that you understand how a digital camera basically absorbs an image of an object, understand how the lens, aperture, and shutter works to get the maximum result of the images captured.

What Kind of Digital Camera is Best For Me?

 After you answer all questions discussed previously about the primary factors to consider before choosing a digital camera, narrow down your choices by understanding the different kinds of digital cameras:

Compact Digital Cameras

• Compact digital cameras are not only small, they are easy to use and offer fewer options to control, which means that this is less confusing. Despite its low cost, this kind of digital camera is capable of producing very good results. Let’s look at the basic features:
• Weighs around 4-10 ounces
• Great for point and shoot
• Fully automatic, which means that this kind of digital camera has no manual settings for aperture and shutter speed.
• You have options though when it comes to settings. Most compact digital cameras offer portrait, macro, snow, sports, landscape, low light, etc.
• You cannot change lenses.
• Slow shutter speed, which means that there’s a few seconds wait time between the time that you depress the shutter until the time that the picture is captured.
• Most compact digital cameras offer a modest zoom of a long focal point.
• You will also find a tiny flash for dark condition and pixel counts ranges from 2 megapixels to as high as 7 megapixels.

Advanced Digital Cameras

• Digital Cameras that are able to produce results to professional standards but lack the sturdiness, durability, and range of accessories are called advanced digital cameras. For an avid nonprofessional photographer, advanced digital cameras offer the best balance between quality and cost. This kind of digital camera is capable of most of the professional tasks while it is lighter, compact and full featured.
• Also called prosumer and bridged cameras
• This kind of digital cameras come in different sizes. This is definitely larger than compact cameras. Some of which looks like DSLR, but lighter. Usually weighs 10 to 20 ounces.
• The only difference between prosumer and DSLR is that prosumer cameras’ lens are fixed but it comes with good, quality zoom lenses.
• Since the lens is fixed, it ensures no dust get onto the sensor.
• Advanced digital cameras can be controlled manually, like DSLR. Some of which comes with attachments for close ups, telephoto filters, and external flashes.

DSLR Cameras (Digital Single Lens Reflex)

• DSLR cameras have imaging capabilities enough to sustain an experienced photographer to a professional level.
• By having this kind of digital camera, you will have the ability to change the lens based on your desired outcome.
• Although there are significantly smaller DSLR, most of which are larger and weighs more.
• This kind of digital camera has the ability to be operated manually to full extent which gives a learned photographer more control over all aspects in photography.
• Definitely costs more than compact and bridged cameras.

What Camera Should I Buy?

The answer to the question “What camera should I buy?” depends primarily on what you want to do with the images.  There are different kinds of digital cameras available, and before you learn the difference between each one of them to narrow down your choices, ask yourself the following questions:

• How much equipment do you wish to carry around?
• What size of digital camera are you willing to take with you?
• What is your understanding level when it comes to photography?
• Do you want more flexibility for creative purposes, or are you contented with simple snapshots?
• And lastly, how much money do you have at your disposal?

To help you decide on what camera should you buy, calculate your budget first, and then decide which features of digital cameras you cannot live without. Finally, prepare yourself to make some compromises.  You might want to consider that older models and secondhand digital cameras offer superb values as well.

When choosing a digital camera, don’t be overwhelmed by the enormous features it has. You are not expected to use all of them; those features were added for marketing purposes. And before purchasing a digital camera, ensure that the model you have chosen is comfortable in your hands-very small digital cameras can be awkward for people with large hands.

Another important consideration is the menu. Make sure that the menu is user friendly, easy enough for you to read, and not too complicated.

There was once a time when we classify digital cameras by their resolution or megapixel count. However, pixel count alone no longer determines how good or versatile a digital camera is. It makes more sense to look at the features and capabilities.

Once you have answered the questions above, narrow down your choices by understanding the different kinds of digital cameras on my next post. Cheers! J

Nikon D3100 Digital SLR Camera

Price $ 699.95 +

The D3100 takes excellent images on automatic with the kit lens. Composition is much easier with a proper viewfinder and the larger sensor makes obtaining shallow depth of field simple.

You would want to purchase Nikon D3100 for its size and weight, but this digital camera has its flaws. You will not be pleased with auto focus, or burst speed. I find making changes in the menus can be tedious. Some reviews also mentioned that there were several times when camera locks up, and the only way to fix it was to remove battery and replace it back.

Nikon D3100 feels great in my hands and nice to use. The ergonomics are perfect. I tested the D5100 and the D90 as well as all the Canon Rebels, and I would say that the D3100 felt the best.

To check how to use  Nikon D3100, download a copy of Nikon D3100 User  Manual. This user manual is from Nikon USA support group and you must have Adobe Reader to read the full text.

Key Features of Nikon D3100 Digital SLR Camera

With Nikon D3100’s 14.2 Megapixel DX-format CMOS Image Sensor, this camera delivers beautiful photographs and prints well beyond 20 x 30 inches.

Full 1080p HD Cinematic Video with full-time autofocus and sound lets you record cinematic-quality movies in Full 1080p HD format (1920 x 1080 pixels).

Featuring Nikon’s Guide Mode with intuitive controls and on-board assistance helping you take better pictures every step of the way.

This digital camera has fast 11-point Autofocus System delivers razor-sharp pictures.

3-in. monitor with One-Touch Live View shooting and movie capture.

Nikon D3100 has built-in HDMI port that lets you connect directly to your HDTV using an optional HDMI cable

Control Image and Movie Playback with most HDTV remote controls

This digital camera has 6 Automatic Exposure Scene Modes Just set the Mode dial to Portrait, Landscape, Child, Sports, Close-up or Night Portrait for stunning results in otherwise challenging conditions.

Picture Control lets you choose from Standard, Neutral, Vivid, Monochrome, Portrait, or Landscape to apply a personal look and feel to your pictures.

Nikon D3100 digital camera has built-in pop-up flash for those times when there isn’t enough light

Includes 3x 18-55mm Zoom-NIKKOR VR Image Stabilization Lens with legendary NIKKOR optical quality and fast, accurate autofocus for vivid color, striking contrast and crisp detail and VR image stabilization to ensure the sharpest hand-held pictures and movies.

Compact and Lightweight Design Beautifully styled..

Split-second Shutter Response of this digital camera eliminates the frustration of shutter delay, capturing moments that other cameras miss.

ISO sensitivity 100-3200, Nikon D3100 has expandable to ISO 12800 equivalent delivers exceptional results, even in the most challenging low-light situations.

Scene Auto Selector lets the D3100 decide the best mode to match the shooting situation when using Live View.

EXPEED 2 Nikon’s new image processing engine assures breathtakingly rich image quality, managing color, contrast, exposure, noise and speed.

This digital camera has Scene Recognition System in Live View which automatically optimizes exposure, autofocus, and white balance, allowing you to obtain beautiful photos without the hassle of making complicated camera adjustments yourself.

Active D-Lighting restores picture-enhancing detail in shadows and highlights.

Automatic Image Sensor Cleaning uses an ultrasonic process and exclusive Airflow Control combats the accumulation of dust in front of the image sensor, safeguarding image quality shot after shot.

In-camera Image Editing allows creative freedom, without the need for a computer, offering easy editing functions.

Nikon D90 Digital SLR Camera

Price $ 899.95 +

The D90 has the flexibility to meet  white balance, and exposure expectations. The menus are extremely well organized and easy to navigate. The top-of-the-camera display is easy to read. The information displayed inside the viewfinder is well organized and configurable. The histogram displays are complete and easy to display.

If you plan to take pictures in rough conditions, (wet, dirty,dusty, extreme cold or heat), you should seriously consider moving further up the Nikon product line as the D90 body is not as tight nor as durable as the top-of-the-line models.

For great results in low light or for indoor situations, one really needs an additional flash.  You will need to use the SB-800 to take exceptional images from great distances as well as wonderful subtle portraits. Try the same with the pop-up and you will be disappointed. Low light without a flash is very good but image editing is usually required.

To check how to use Nikon D90, download a copy of Nikon D90 User Manual. This user manual is from Nikon USA support group and you must have Adobe Reader to read the full text.

Key Features of Nikon D90 Digital SLR Camera

12.3-megapixel DX-format CMOS imaging sensor: Coupled with Nikon's EXPEED image processing technologies and NIKKOR optics, breathtaking image fidelity is assured.

World’s first digital SLR camera with an HD movie mode: Record exceptional 24fps movie clips with sound at up to 720p HD (1280 x 720 pixels) in Motion JPEG format, enhanced by NIKKOR interchangeable lens quality and versatility.

This digital camera has 3-inch super-density 920,000-dot color LCD monitor: High resolution, 170-degree wide-angle viewing guarantees confident image review and movie playback.

11-point AF system: Consistently fast and accurate autofocus, reinforced by the Nikon Scene Recognition System, delivers razor sharpness in a wide variety of conditions.

Nikon D90 has 3D Color Matrix Metering II with Scene Recognition System: Nikon's renowned 420-pixel RGB 3D Color Matrix Metering II, teamed with the exclusive Scene Recognition System, evaluates images, referencing an on-board database of over 30,000 photographic scenes, for unmatched exposure accuracy.

This digital camera has Auto Active D-Lighting: Selectable and Automatic, Active D-Lighting optimizes details within shadows and highlights, taming high-contrast situations in real time.

In-Camera Image Editing: Creative freedom stems from exclusive in-camera image editing, featuring Fisheye effect, Straighten and Distortion Control as well as D-Lighting, Red-eye Reduction, Image Overlay, Monochrome and more.

Nikon D90 is capable of continuous shooting as fast as 4.5 frames-per-second: Combined with fast 0.15ms power-up and split-second 65ms shooting lag, dramatic action and decisive moments are captured easily.

Low noise ISO sensitivity from 200 to 3200: High signal-to-noise components and design deliver exceptional performance, even at high ISO setting.

This digital camera has built-in image sensor cleaning: Effective 4-frequency, ultrasonic sensor cleaning frees image degrading dust particles from the sensor's optical low pass filter.

One-button Live View: Easy to use Live View activates access to 3 contrast detection focus modes including Face Priority AF.

Comprehensive exposure control: Five advanced scene modes plus Program Auto, Shutter Priority, Aperture Priority and Manual.

Nikon D90 has durable, high precision shutter: Testing to over 100,000 cycles assures shutter life and accuracy.

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Nikon D700 Digital SLR Camera

Price $ 2,699.95 +

I recommended Nikon D700 to students and other professionals who wanted a multi-featured camera they could grow with. If you can't afford D3, buy D700 instead. Don't get me wrong, Nikon D3 is a wonderful full frame camera to have if you have the extra few thousand dollars to spend. D700 gives you the same quality as NikonD3 can offer, if you do not care too much on using high ISO. Since Nikon D700 is cheaper, you can invest in a nicer lens instead.

Being a full frame camera, D700 can provide exceptional image quality in low light conditions without seeing too much noise when using higher ISO. It is also great for landscape photography if attached to a wide angle lens and a good tripod.

To check how to use Nikon D700, download a copy of Nikon D700 User  Manual. This user manual is from Nikon USA support group and you must have Adobe Reader to read the full text.

Key Features of Nikon D700 Digital SLR Camera

Nikon's original 12.1-megapixel FX-format (23.9 x 36mm) CMOS sensor: Teamed with Nikon's exclusive EXPEED digital image processing, the D700 delivers breathtakingly rich image quality.

This digital camera is capable of continuous shooting up to 5 frames per second: Shoot at up to 8 frames per second with the optional MB-D10 Multi-power Battery Pack.

Nikon D700 has two Live View shooting modes: Choose from hand-held or tripod modes to suit shooting requirements.

Fast, accurate 51-point AF with 3D Focus Tracking: Exacting autofocus precision, plus three Dynamic AF modes.

This digital camera has 1,005-Pixel 3D Color Matrix Metering II: Legendary Nikon exposure accuracy aided by an onboard database of over 30,000 images.

Nikon D700 has Picture Control settings: Advanced color control with 9 customizable settings and 4 preset options allow fine tuning of image appearance preferences.

This digital camera has broad ISO sensitivity up to 6400 and incredibly low noise: Super low-noise performance from 200-6400 ISO, with the added versatility of Lo-1 (100 ISO) Hi-1 (12,800 ISO) and Hi-2 (25,600 ISO).

Three-Inch, super-density 921,000-dot VGA color monitor: High resolution with

170-degree wide-angle viewing, calibrated color and tempered-glass protection assure confident image review.

Rugged magnesium-alloy construction: Along with extensive dust and moisture protection and a durable shutter mechanism tested to 150,000 cycles, the D700 merges pro D-SLR performance with expanded agility.

Nikon D700 digital SLR camera has dynamic Integrated Dust Reduction System: Effective quad-frequency, ultrasonic sensor cleaning minimizes image degrading dust particles.

Nikon's exclusive Scene Recognition System: SRS further extends auto-exposure intelligence while also advancing white-balance detection and autofocus performance.

Active D-Lighting with NEW Auto mode: Unique three-phase dynamic control to capture previously lost details in shadows and highlights while maintaining normalized contrast.

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Canon EOS Rebel T3 Digital SLR Camera

Price $ 599.99 +

This digital camera is user-friendly. As soon as you open the box, you can easily identify most of the functions. The button-layout is comfortable and the menu is self-explanatory. There is just one minor issue that you might find which is when switching from LCD mode to Live View mode, its a bit close to the shooting option/self timer button. In some cases when taking night landscaping shots, one may accidentally hit the wrong button.

For those who have used XSi and T1i, Rebel T3 body construction is a little cheap when compared to any other SLR's in the market.

• To check how to use Rebel T3, download a copy of Canon Rebel T3 User Manual. This user manual is from Canon USA support group and you must have Adobe Reader to read the full text.

Key Features of EOS Rebel T3 Digital SLR Camera

Canon's CMOS sensor captures images with exceptional clarity and tonal range, and offers the most pixels in its class. It offers many of the same new technologies to maximize each pixel's light gathering efficiency that were first seen with the professional EOS-1D Mark III model.

EOS Rebel T3 enables shooting from sunrise to sunset and helps ensure capture of the finest detail. With enhanced high-sensitivity optimization, subjects can be captured clearly and easily at high shutter speeds without flash, with minimized blur and noise.

This digital camera’s expanded repertoire of technologies includes shooting video in brilliantly clear, exactingly sharp high definition for playback on your HDTV! Shooting at 1280 x 720 at 30 (29.97) or 25 frames per second, HD video can be taken immediately through the EOS Rebel T3 camera's intuitive operation and layout.

EOS Rebel T3 has a high-precision, 9-point AF system utilizing a high-precision, f/5.6 cross-type center point.

This digital camera features Canon's newest Dual-layer sensor, with 63 zones. By measuring not only the amount of light, but also taking into account color and luminosity, this new system delivers a very high level of accuracy for better results every time.

EOS Rebel T3 operates with such effortless speed that operation is nothing short of intuitive. With instant startup times, speedy autofocus and minimal shutter lag, the EOS Rebel T3 is one of the fastest cameras available today.

Rebel T3 has a huge, bright 2.7-inch TFT (thin film transistor) LCD monitor with 230,000 pixels and a viewing angle of 170°.

The EOS Rebel T3 DSLR's Quick Control screen gives you instant access to the most common settings, all in one place! It's a great way to quickly confirm or change settings while you're shooting. The Quick Control screen is particularly useful when you're shooting from a tripod or monopod.

This digital camera demystifies great photography by including an in-camera Feature Guide. Appearing on the camera's LCD, the Feature Guide displays a simple description or advice for the respective function.

Canon EOS 50D Digital SLR Camera

Price $1,099.00 +

This digital SLR digital camera’s high ISO quality is outstanding and does as claimed, represent at least a full stop improvement over any Canon camera before it. It is very similar to the 40D in all controls, so it's completely easy to switch from one to the other. The motor drive is fast enough for action. Live view is so much better than 40D, Tripod is still a must but that is expected. Brighter screen is a plus in any landscape work.

I have to say that I prefer EOS 50D to the 7-D or even the 5D MkII. From what I heard,  50D produces comparably less shadow noise than either digital cameras, and the RAW files are quite flexible beyond what you would have expected. I've read that some people mentioned about getting the magenta cast on the photo, and colors are flat. But considering we have a lot of photo editing software now, those can be corrected at the post production. One review that I can’t afford to neglect was when EOS 50D is used to shoot outdoor in a sunny day, highlights are blown out pretty badly, especially in light color objects. Even though Highlight Tone Priority function comes handy in those situations, they were pretty ugly noticeable which you won’t get comparing to 20D.

• To check how to use EOS 50D, download a copy of Canon EOS 50D User Manual. This user manual is from Canon USA support group and you must have Adobe Reader to read the full text.

Features of Canon EOS 50D Digital SLR Camera

• EOS 50D features a newly-designed 15.1-megapixel APS-C sized CMOS sensor which is capable of recording up to 4752 x 3168 pixels with full 14-bit A/D conversion for extremely fine tonal gradation.

• This digital camera operates with such effortless speed that operation is nothing short of intuitive. With instant start-up times, speedy autofocus and minimal shutter lag, the EOS 50D is one of the fastest cameras available today. It can shoot up to 6.3 fps, in bursts of up to 90 JPEGs (using an UDMA CF card), 60 JPEGs (using a CF card) consecutively or 16 RAW files.

• EOS 50D features a bright, high resolution, 3.0-inch Clear View LCD monitor with 920,000 (dots/VGA) pixels and a broad viewing angle of 160° horizontally and vertically. It offers a brighter and more detailed display than the EOS 40D.

• This digital camera features Canon's most advanced Live View shooting thanks to the number of focusing modes available including Quick mode, Live mode and Face Detection Live mode.

• Canon EOS 50D Digital SLR Camera has a high-precision 9-point wide area AF that uses cross-type points at f-stops of f/5.6 or faster, enabling the camera to focus faster, more accurately, and in difficult lighting situations. AF sensitivity is a stunning EV-0.5 to EV18.

• Canon's exclusive Lens Peripheral Illumination setting takes into account any light falloff in the corners of the frame and corrects it, making for a perfectly exposed image.

• This digital camera’s Self Cleaning Sensor Unit eliminates stray dust that enters the camera when changing a lens or when out in the field.

• The EOS 50D has a new Creative Auto mode and a quick control screen that helps novice users narrow the gap between fully automatic and manual control.

This digital camera includes a new HDMI (High Definition Multimedia Interface) output device that enables high definition display of your photographs on any HDTV with HDMI ports.