Digital SLR

Digital Single Lens Reflex

1. How does it work?

DSLR cameras use a system called a mechanical mirror and pentaprism that is placed behind the lens of the camera so that it can direct the light from the lens toward the optical viewfinder which is like an eye piece so that one can view the object to be taken.

Light travels through the lens towards the primary mirror where then it refelects the light traveling through the lens upwards, through an angel of 90 degrees towards the pentaprism. It is incorporated into a SLR camera to allow the incoming image to be flipped, which then enables one to view the image throughthe viewfinder. The diagram below shows how light travels through the lens towards the primary mirror:

image above from: http://mybestdigitalcamera.com/wp-content/uploads/2009/03/nikon-coolpix-p90-121mp-digital-camera.jpg

http://mybestdigitalcamera.com/wp-content/uploads/2009/03/dslr-cross-section1-300x260.png

During exposure, upon releasing of the shutter, the mirror quickly swings out then the shutter opens, causing the light to go from the lens through the project directly to the image sensor. This causes the temporal black out of the viewfinder. This period is referred to as viewfinder vlackout. A second shitter then covers the sensor, making the end of the exposure which then leads to the mirror lowering while shutter resets to normal mode.

Source: http://mybestdigitalcamera.com/148/how-does-a-digital-slr-camera-work/


2. Who are the leading providers for the said device?

Most of the main digital SLR camera makers were also producers of 35mm slr cameras and lenses including the big five: Nikon, Canon, Olympus, Pentax and Minolta. Sadly Minolta parted company with digital slr cameras and sold the division to Sony. Other new companies in the market include electronic giants Panasonic and Samsung. The newer companies have managed to get a foothold in the digital slr market by collaborating with established camera makers. Panasonic works with Leica while Samsung has formed a partnership with Pentax.

Source: http://www.slr-digital-camera.com/digital-slr-makers.html


3. How does it differ from other similar devices?

Digital SLRs are digital cameras. The major differences between dSLRs and digicams, otherwise known as "point-and-shoot" cameras, are:

• The size of the sensor

This is either a CCD or a CMOS chip. Digicams use very small sensors, mostly for economic reasons: they become vastly more expensive to make the larger they become. This manifests itself as deeper depth of field and higher noise, generally speaking.

• The size of the camera itself

At its heart, a dSLR is a mechanical device with digital insides. The "SLR" part of the camera, either a pentamirror or a pentaprism, is physically difficult to make smaller, so the rest of the camera can only be scaled down so much. Ergo, dSLRs are big! Digicams don't suffer from the same restriction, since they don't use a reflex system to focus, and often lack viewfinders entirely. They also benefit from their reduced sensor size and the associated reduction in the size of off-chip electronics.

• Interchangeable lenses

Point-and-shoot cameras come with a single fixed lens that tends to do everything pretty well. dSLRs can be equipped with many different lenses depending on your needs, some of them much better than digicam lenses, and, yes, some of them dramatically worse.

The rest of the differences are minor, and have more to do with AF arrays and marketing and other nonsense than taking pictures. Both digicams and dSLRs take excellent pictures. Ultimately the decision to purchase one over the other comes down to what sort of work you do, and it's worth adding that many enthusiasts own both.

Source: http://in.answers.yahoo.com/question/index?qid=20090322233312AAduO5k


4. What is the device used for?

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.

Source: http://in.answers.yahoo.com/question/index?qid=20090322233312AAduO5k


5. Are there other possible uses for the device aside from what it is designed for?

The most recent DSLRs are now integrated with video capturing for those who are also interested in film/video production.