DSLR lenses

The ability to exchange lenses, to select the best lens for the current photographic need, and to allow the attachment of specialized lenses, is a key to the popularity of DSLR cameras

Lens mounts and lens manufacturers
Further information: Crop factor
Interchangeable lenses for SLRs and DSLRs are built to operate correctly with a specific lens mount that is generally unique to each brand. A photographer will often use lenses made by the same manufacturer as the camera body (for example, Canon EF lenses on a Canon body) although there are also many independent lens manufacturers, such as Sigma, Tamron, Tokina, and Vivitar, to name a few, that make lenses for a variety of different lens mounts. There are also lens adapters that allow a lens for one lens mount to be used on a camera body with a different lens mount but with often reduced functionality.



Many lenses are mountable, "diaphragm-and-meter-compatible", on modern DSLRs and on older film SLRs that use the same lens mount. Most DSLR manufacturers have introduced lines of lenses with image circles and focal lengths optimized for the smaller sensors generally offered for existing 35 mm mount DSLRs, mostly in the wide angle range. These lenses tend not to be completely compatible with full frame sensors or 35 mm film because of the smaller imaging circle and, with some Canon EF-S lenses, interference with the reflex mirrors on full-frame bodies. Several manufacturers produce full-frame digital SLR cameras that allow lenses designed for the 35 mm film frame to operate at their intended angle of view.

DSLR design principles

DSLR design principles

1. 4-element lens
2. Reflex mirror
3. Focal-plane shutter
4. Image sensor
5. Matte focusing screen
6. Condenser lens
7. Pentaprism
8. Eyepiece

Cutaway of an Olympus E-30 DSLR
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A DSLR cutaway diagram



A camera based on the single-lens reflex (SLR) principle uses a mirror to show in a viewfinder the image that will be captured. The cross-section (side-view) of the optical components of an SLR shows how the light passes through the lens assembly , is reflected into the pentaprism by the reflex mirror (which must be at an exact 45-degree angle) and is projected on the matte focusing screen . Via a condensing lens and internal reflections in the roof pentaprism the image is projected through the eyepiece to the photographer's eye. Focusing is either automatic, activated by pressing half-way on the shutter release or a dedicated AF button, as is mainly the case with an autofocusing film SLR; or manual, where the photographer manually focuses the lens by turning a lens ring on the lens barrel.

When an image is photographed, the mirror swings upwards in the direction of the arrow, the focal-plane shutter opens, and the image is projected and captured on the sensor , after which actions, the shutter closes, the mirror returns to the 45-degree angle, the diaphragm reopens, and the built in drive mechanism re-tensions the shutter for the next exposure. There is often a ring of soft material around the focusing screen, which helps to both cushion the impact of the mirror slapping up and helps seal the mirror box from light entering through the eye piece. Some high-end cameras incorporate a shutter into the eyepiece to further eliminate light that may enter there during long exposures.


Phase-detection autofocus
The diagram shown here is an over-simplification in that it omits the sensors used to activate the drive for the autofocus system. Those sensors reside at the bottom of the mirror box. In such a system, the main mirror is slightly translucent in the center, which allows light to pass through it to a secondary mirror which reflects light to the sensors below.



DSLRs typically use a phase detection autofocus system. This method of focus is very fast, and results in less focus "searching", but requires the incorporation of a special sensor into the optical path, so it is usually only used in SLR designs. Digicams that use the main sensor to create a live preview on the LCD or electronic viewfinder must use contrast-detect autofocus instead, which is slower in some implementations.

DSLR optical viewfinder vs. digital point-and-shoot camera LCD
Depending on the viewing position of the reflex mirror (down or up), the light from the scene can only reach either the viewfinder or the sensor. Therefore, many older DSLRs do not provide "live preview" (allowing focusing, framing, and depth-of-field preview using the display), a facility that is always available on digicams although today most DSLRs offer live view.

The advantages of an optical viewfinder are that it alleviates eye-strain sometimes caused by electronic view finders (EVF), and that it constantly shows (except during the time for the sensor to be exposed) the exact image that will be exposed because its light is routed directly from the lens itself. Compared to ordinary digital cameras with their LCDs and/or electronic viewfinders the advantage is that there is no time lag in the image; it is always correct as it is being "updated" at the speed of light. This is important for action and/or sports photography, or any other situation where the subject or the camera is moving too quickly. Furthermore, the "resolution" of the viewed image is much better than that provided by an LCD or an electronic viewfinder, which can be important if manual focusing is desired for precise focusing, as would be the case in macro photography and "micro-photography" (with a microscope).

Compared to some low cost cameras that provide an optical viewfinder that uses a small auxiliary lens, the DSLR design has the advantage of being parallax-free; that is, it never provides an off-axis view.

A disadvantage of the DSLR optical viewfinder system is that while it is used it prevents the possibility of using the LCD for viewing and composing the picture before taking it. Some people prefer to compose pictures on the display – for them this has become the de-facto way to use a camera. Electronic viewfinders may also provide a brighter display in low light situations, as the picture can be electronically amplified; conversely, LCDs can be difficult to see in very bright sunlight.


Comparison with digital point-and-shoot camera
The reflex design scheme is a major difference between a DSLR and an ordinary digital point-and-shoot camera, which typically exposes the sensor constantly to the light projected by the lens, allowing the camera's screen to be used as an electronic viewfinder.

Source: http://en.wikipedia.org

Digital single-lens reflex camera

Most digital single-lens reflex cameras (digital SLR or DSLR) are digital cameras that use a mechanical mirror system and pentaprism to direct light from the lens to an optical viewfinder on the back of the camera.


The basic operation of a DSLR is as follows: for viewing purposes, the mirror reflects the light coming through the attached lens upwards at a 90-degree angle. It is then reflected three times by the roof pentaprism, rectifying it for the photographer's eye. (Note that the diagram below incorrectly shows a non-roof pentaprism.) During exposure, the mirror assembly swings upward, the aperture narrows (if stopped down, or set smaller than wide open), and a shutter opens, allowing the lens to project light onto the image sensor. A second shutter then covers the sensor, ending the exposure, and the mirror lowers while the shutter resets. The period that the mirror is flipped up is referred to as "viewfinder blackout". A fast-acting mirror and shutter is preferred so as not to delay an action photo.

All of this happens automatically over a period of milliseconds, with cameras designed to do this 3–10 times per second.

DSLRs are often preferred by professional still photographers because they allow an accurate preview of framing close to the moment of exposure, and because DSLRs allow the user to choose from a variety of interchangeable lenses. Most DSLRs also have a function that allows accurate preview of depth of field.

Many professionals also prefer DSLRs for their larger sensors compared to most compact digitals. DSLRs have sensors which are generally closer in size to the traditional film formats that many current professionals started out using. These large sensors allow for similar depths of field and picture angle to film formats, as well as their comparatively high signal to noise ratio.

The term DSLR generally refers to cameras that resemble 35 mm format cameras, although some medium format cameras are technically DSLRs.

Source: http://en.wikipedia.org

Tips for Choosing a Digital Camera

Choosing a digital camera is certainly not easy. One bought a camera can be minimized by reading a guide to search for digital cameras. Different activities would also require a different camera for each person. The camera is portable, lightweight, high durability, is a type of compact cameras just to portraits and family recreation if not too deep photography. While the camera with a zoom lens, high resolution, the feature IS / Micro, etc., is more suited to the professional grade photography. So the point is kind of a person's activities to determine the path to search for digital cameras.

1. Resolution
Price camera is directly proportional to the resolution of images produced on the camera. Catcher or CCD image sensor is the cause of the magnitude of the resolution of the camera. A CCD sensor can have millions of points of light catcher. In order to get good results, for the professional class would at least look for a digital camera with a minimum resolution of 5 Megapixels.



2. File Transfer
The camera output average current is already using the USB connection port to send the results file snap. This requirement is mandatory, why, the USB port will facilitate the maintenance of files on the camera or photo printing process. Moreover, if you can find a camera that has a feature DPOF / Digital Print Order Format is print photos without a computer through so directly connect to the printer.


3. Zoom
To the layman, the zoom is a list that must be met to find a digital camera. Zoom is useful for capturing images from a distance. Zoom will be easier in taking lots of pictures.

4. LCD Display
LCD Display greatly assist the process of setting the camera as it is used in any activity. Find the digital camera that has an LCD display is easy, large size, and simple and understandable. LCD with live preview feature also helps in taking photographs with the angel a little harder than a peek of the view finder.

5. Memory
Imagine taking three times and then fill the memory is full and needs to be replaced will be very troublesome. Perhaps less extreme example above. Internal and external storage capacity memory card in the camera needs to be addressed. The bigger, the better course to accommodate a lot of pictures.

Explanation of How To Work On Digital Cameras

Digital cameras are electronic devices that capture images and store them in digital memory, no longer needs the help of the media of film to snap. The workings of digital cameras occurs when we press the shutter button. the workings of digital cameras



1. We shoot pictures of trees with a digital camera. The light comes from the tree image to the camera and the camera lens. The task is to put a shadow image lens toward the CCD sensor.

2. CCD (Charge Coupled Device) or known as a CCD sensor is a device that captures an image size of a fingernail works or just assume for a micro sd card mobile phones. CCD sensors have many points / grids are very sensitive to light. The resulting image will be higher resolution and more refined if you have a lot of point sensors. The greater the number of sensor points directly proportional to the number of pixels is generated. A CCD sensor can have millions in it. Brightness of each color of RGB (Red Green Blue) will be stored in a single sensor point. So the task of CCD is capturing analog signals / images and turn them into electrical signals.



3. The process of image compression format (eg RAW / JPEG) by the way digital cameras work done on the image processing part that converts electrical signals into digital signals by converter ADC (Analog / Digital Converters)



4. Once the image is converted into a digital signal, it will be processed by a computer chip processors that each camera. Additional features provided in the form of chip software (firmware) which have different abilities depending on the digital camera manufacturers (example: Casio / Kodak / Canon / Pentax / Olympus) is. The software on the camera also determine the final outcome resulting picture. Some features available such as sepia, black & white, backlight, white balance, face recognation, anti shake, super steady shot, vibration reduction, etc..



5. The last process is the workings of a digital camera to send digital data to be stored on the memory card. SD or CF is one example of memory cards in digital cameras.

Know Your Digital Camera Lens Guide

When talking about the camera, there is a tool that is quite interesting. The tool is a lens, a camera lens is the most important thing in the camera body. Focuses an image of the tentacle light sensor, only that the function of the lens. Simple, but very expensive and drain the pockets deep enough. Types and strengths of each camera lens is also different. To clarify about the lens, please see the following several types of lenses:


1. Wide lens
This lens has a size of 18mm / 24mm / 28mm in focal distance lengthnya. Wide lens serves to take a picture that has a large area and wide-angle field. For fans of scenery and landscape, usually choose this lens as the primary weapon of the photographer.



2. Standard lens
This lens has a 50mm size. Spacing photos is not too far or not too short. Fitting for the photos frequently used daily in a variety of purposes.


3. Telephoto lenses
This lens has a size of about 100mm / 200mm / 300mm / 800mm. The function of the camera lens was take a picture from a distance. Because of the distance from the CCD to the lens so far, so shooting can be very far away. Usually used to take pictures at sports arenas, seminars, or photos of birds images of natural samples.
So is the base of the camera lens, to find out more, please see the other articles that discuss the camera lens.

DSLR What Is Right For Entry Level

The camera used for the beginner should be quite affordable in terms of price. DSLR for beginners would be better if you look at the entry level market. Not only the cost affordable by all people, the facilities provided more okay despite some reduction. Should be as fast as a camera user friendly for beginners is a good camera.

Bought in class DSLR for beginners (entry level) should adjust according to the existing budget. Remember, there is no best camera. Each year, the camera continues to grow with more new features. But, all the standard camera about the camera world the same. A key part of most photography is the lens. Camera body will shrink resale value after purchase, while the lens does not come down in price and become its own investment resources for some circles. So, identify existing camera specifications and in accordance with the needs and abilities will be more comfortable hearts.

Today there will be some reviews of cameras that are suitable for newcomers to the photography class. DSLR for a beginner this can be taken into consideration if you want. In terms of features supplied by each manufacturer is also good. For more details, please review the following cameras:

Nikon D3000



# Price: + / - Rp4.500.000
# 10.75 DXformat MP CCD sensor
# 3-inch LCD display monitor
# Shakes and airflow sensor (image sensor cleaning)
# 11 AF points
# ISO 100 to 1600
# 3 fps continuous shooting
# EXPEED image processing engine
# Calendar view and 72 thumbnail
# Extensive in-camera retouching

Basic tutorial Camera Lenses

The lens is the most vital tool in the camera. Without the lens, the camera can not capture or record images. Nothing will continue to film portrait pictures of objects or sensors capture images from a digital camera unless done by a lens. To learn more about the lenses. Here is the important part is to know about digital camera lenses.




First, the shape of the lens is divided into two types. Zoom lens or prime lens / fixed. Zoom lens has a greater ability on the spacing of flexible focal length / lens focal range and has a heavier mass. While certainly more lightweight prime lens, focal length between lens and image sensor are fixed catcher / can not change, and have better optical quality.

Digital Camera lenses have different focal lengths. Differences focal length / lens focal range can affect the ability of taking pictures and images taken of the results. Click the focal length if not understand about the focal length. For more details, there are three types of lenses in general:

1. Wide lens (fisheye / fish eye lens) is a lens that has a focal length range of about 8mm to about 16mm. This type of lens is best used for capturing landscapes, buildings, or a very wide area.

2. Standard lens is a lens that has a focal length of about 18mm to 55mm. Most people assume as a 55mm standard lens. Standard lens is used for various purposes.

3. Tele or a telephoto lens is a lens that has the longest focal length is about 55mm to 800mm. Usually used to take photos from a great distance, such as taking shots of birds flying, soccer sports activities, animals in debt, and shoot away at the seminar.



The lens also has a wide range of standard features that most are now owned by many manufacturers of digital camera lenses. These features include:

1. IS / VR (Image Stabilization / Vibration Reduction) feature that reduces vibration at low shutter speed. Or the effects of vibration on the hand by accident. Very handy for taking pictures of still or not moving.

2. Macro feature that the camera used to photograph close-up photos eg flower, insects, and various small objects to make it look sharper. But to get more results about the class hunting small objects, it's good to have a separate macro lens.

3. AF-S/SDM/USM/HSM (Auto Focus) is a feature to move my focus to the motors automatically on a digital camera lens.

DSLR design considerations

Pentaprism vs. penta-mirror
Most of the entry level DSLRs use a pentamirror instead of the traditional pentaprism. The pentamirror design is composed mostly of plastic and is lighter and cheaper to produce — however, the image in the viewfinder is usually darker.

Sensor size and image quality

Image sensors used in DSLRs come in a range of sizes. The very largest are the ones used in "medium format" cameras, typically via a "digital back" which can be used as an alternative to a film back. Because of the manufacturing costs of these large sensors the price of these cameras is typically over $20,000 as of December 2007.




With the exception of medium format DSLRs, the largest sensors are referred to as "full-frame" and are the same size as 35 mm film (135 film, image format 24×36 mm); these sensors are used in high-end DSLRs such as the Canon EOS-1Ds Mark III, the Canon EOS 5D Mark II, the Nikon D700, the Nikon D3, the Nikon D3X, the Sony Alpha 850 and the Sony Alpha 900. Most modern DSLRs use a smaller sensor commonly referred to as APS-C sized, that is, approximately 22 mm × 15 mm, a little smaller than the size of an APS-H film frame, or about 40% of the area of a full-frame sensor. Other sensor sizes found in DSLRs include the Four Thirds System sensor at 26% of full frame, APS-H sensors (used, for example, in the Canon EOS-1D Mark III) at around 61% of full frame, and the Foveon X3 sensor at 33% of full frame.


The sensors used in current DSLRs are much larger than the sensors found in digicam-style cameras, most of which use sensors known as 1/2.5", whose area is only 3% of a full frame sensor. Even high-end digicams such as the Canon PowerShot G9/G10/G11 or the Nikon CoolPix P5000/P6000 use sensors that are approximately 5% and 4% of the area of a full frame sensor, respectively. The current exceptions are the Micro Four Thirds system by Olympus and Panasonic, the Sigma DP1, which uses a Foveon X3 sensor, and the Leica X1. Leica offers an "S-System" DSLR with a 30×45mm array containing 37 million pixels. This sensor is 56% larger than a full-frame sensor.


There is a connection between sensor size and image quality; in general, a larger sensor provides lower noise, higher sensitivity, and increased latitude and dynamic range. There is also a connection between sensor size and depth of field, with the larger sensor resulting in shallower depth of field at a given aperture.

Source: http://en.wikipedia.org

How do I filter the camera before purchase

There are many things to think about before buying a camera and decide which would be the companion of life for some period of time. Before making a purchase, should understand the guidelines for how to buy a camera. At least there are some things to note are as follows:



1. Funding
Important factor of buying cameras is money. Without money there is not any camera that can be bought. Look at the number of savings and financing available, whether few or many. If funding is a lot, then it can simply buy a pretty nice. But still be careful because dicamera kususnya investment in buying electronic goods always come down drastically with the rapid time frame. But when the little funding, briefly delaying saving to buy a camera with a camera that also targeted a wise thing.

2. Function
What is the function using a digital camera. Is it just for hobby, or something important that is for jobs, or simply as a lifestyle / life style, or may also be an investment - for example buy camera lens. Buy according to the purpose, because it can save expenses.

3. Type
Specification there are two types of camera type. First is the type of DSLR, this type is used for photography classes. While the pocket is used for everyday purposes. Not too much need for high resolution or clarity of image features.

4. Resolution
Choose where necessary? Want to print or just viewed it. Required for printing high enough resolution, at least have a 3MP. For everyday use, 2MP is more than enough. Remember that the resolution did not specify the image quality is key.

5. Battery
Initially the battery is not taken into account. But try if the battery is discharged or damaged. That is one thing that sucks. To that end, the battery power supply specially finished materials for consideration. There are two types of battery, one that is rechargeable battery / charger - for example Lithium, and other skali battery life - eg AA Alkaline.

6. Zoom
If you want to enter in the entry-level class camera. Note whether the camera provides the optical zoom feature. Do not get upside down with digital zoom. Optical and digital zoom are very different. In digital zoom, approach / enlargement of an object can influence the outbreak of the image. While the optical zoom is purely an extension of the focal length of the image capture sensor.

7. Recommended for low-light
There are several kinds of features that can be used to help the poor lighting. For example I would like to take pictures ria in a room is less light. Or even in nighttime conditions. Try searching features a high ISO camera, or camera contained strobe light, or flash. ISO is a nice feature to overcome the lack of lighting, but the ISO excessive noise can cause great as well. Buy a camera according to the character of the photographers themselves, all the better.

8. Test test
The test is something you should do before buying camera. At least if not a purchase transaction online, can certainly try first camera purchased. Do not be too hasty in determining good test or not. The test is basically the quality of goods in addition to checks, also tried to get acquainted with the camera. A good camera is usually more userfriendly and easy to understand. Check the LCD display systems and learn, easy or difficult in mengoprasikannya. Try the hand-held camera, whether it has been comfortably in the palm of the hand. Or, try the view finder, feel enjoyable and user friendly camera.

Things above are a few tricks before buying camera. Hope can be useful and fun to find and buy a camera.

Understanding DSLR Camera

DSLR is an abbreviation of the digital single lens reflex. SLR digital camera to function as a camera to take shots at large images through a process of mechanical and electronic. It's just that, often used by professionals in the photography class. This camera is a direct development of SLR cameras are electronic devices be added to the turn sensor light catcher. If it had been using film SLR cameras as sensors capture light, slr digital camera using an electronic device called a CCD or CCD sensor is known.




In general, digital SLR cameras are divided in the chart is important. Among them is the view finder to see the state at the time pemrotretan. LCD display to set the camera feature information. Diaphragm to regulate the size of the incoming light. Camera lens serves as a reflector of light to the CCD sensor. Shutter speed function as a determinant of the shooting. Then the focus to adjust image sharpness in the form of mechanical device or automatic motor.



Rapid development occurred in the view finder or digital slr camera's viewfinder. If the initial view finder is a direct reflection of the process of secondary lens-shaped reflecting pentaprism before the shutter is pressed. So this time, the viewfinder can already be transferred to the LCD display. Feature or a live preview live preview is a feature that helps and so an alternative view-finder. This feature was originally introduced by Olympus E-10 in 2000. In the digital SLR camera is definitely using electronic storage media for data results in the form of memory cards snap. Several types of memory card which is quite widely known of which are compact flash (CF), secure digital (SD) and multimedia card (MMC).