What is digital single lens reflex camera

Digital SLR Camera - How Does an SLR Camera Work?

Professional photographers rely on the digital SLR camera. In 1861 the inventor Thomas Sutton constructed the first device of this type and from then on the principle has been continuously improved. Today's trend is towards digital single-lens reflex cameras (DSLR). The basic technical principle here is the same as for analog models. However, instead of the analog photo film, a digital image sensor is used for the DSLR's image recording.

Topic overview:


The digital reflex camera and its functions


Snapshot (c) Dieter Huemmer / pixelio.de

The basic principle for the digital SLR camera is that the incident image, after it has passed the objective lenses, falls on a mechanically tiltable mirror, which directs the light either towards the viewfinder or onto the image sensor when taking the picture.

Before shooting with the DSLR


Before taking the picture, this tiltable mirror deflects the incoming image vertically upwards. Here it first falls on a screen. This component essentially consists of a glass or plastic pane, which appears matt on one side and clear and transparent on the other. The image of the penetrating light now appears on the matt side. Another mirror-lens system redirects the subject further into the viewfinder of the DSLR and thus into the eye of the beholder. Through the digital reflex camera, the photographer only sees the image on the pane and can optimize contrast and sharpness by making fine adjustments to the lens.

What happens when a single lens reflex camera is triggered?


When the shutter release is activated, the built-in mirror tilts into a position in which it no longer deflects the incident light. The subject now falls straight through the main lens onto the photo film or the digital image sensor of the DSLR. The path from the lens to this film level corresponds exactly to the path from the lens to the focusing screen, which is why exactly the same motif is created when the picture is taken as the viewer saw in the viewfinder before. The digital SLR camera shows the final image before the shutter is released.

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Advantages of the DSLR principle


A digital reflex camera shows the exact image in the viewfinder (c) Bernd Sterzl / pixelio.de

Since the digital image sensors of a DSLR are covered by the mirror, except when triggered, and are therefore only active for a short time, there is less image noise and the digital single-lens reflex camera also saves energy. In addition, the image sharpness can be set much more precisely before recording with the help of the focusing screen image than would be possible on the digital screens of modern cameras. The viewfinder in the DSLR is not limited by the quality and resolution of a screen, but shows the original image.

Digital vs Analog SLR


The obvious advantage of the digital single-lens reflex camera over the analog technology that was used in the past is of course the digital presence of the image material. The DSLR does not require expensive films that have to be developed and only show after 2 weeks whether the picture is successful. Everything is stored digitally on the memory card and can be transferred from the reflex camera to the computer via a card reader or USB connection within seconds.

The analog single-lens reflex camera works with photographic films that are developed into the final image through incident light and chemical processes. As advanced as these processes may be, they are still not protected against errors, for example due to inadequate material. This source of error is avoided with the digital reflex camera compared to the analog SLR

Even if many nostalgics and photo artists swear by the analog single-lens reflex camera, the DSLR has a clear advantage especially in the age of digitization and the world wide web

Digital SLR models


Anyone who decides on a digital SLR camera will probably be overwhelmed by the range of different DSLRs in all possible price ranges. Should it be a reflex camera for beginners or the professional model for several thousand euros?

There are many digital SLR cameras on offer, but there are a few basic criteria to look out for when choosing the right DSLR:

      • What is the digital reflex camera used for? Do you want to take professional photography or just take good quality family photos?

      • The decisive factor for the image quality of a DSLR is the resolution. It is given by megapixels.

      • Do you value a digital reflex camera with special features and mechanisms or do you want to work manually?

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Most popular and best SLR cameras of 2013


These are the 20 most popular and best digital SLR cameras from the DSLR test 2013 by Chip.de:

[learn_more caption = "The 20 best DSLRs in the test"]

  1. Sony Alpha 57
  2. Sony Alpha 65
  3. Pentax K-30
  4. Olympus OM-D E-M5
  5. Sony Alpha 58
  6. Pentax K-5 II
  7. Sony NEX-6
  8. Panasonic Lumix DMC-G6
  9. Nikon D7000
  10. Sony Alpha 37
  11. Samsung NX20
  12. Olympus Pen E-PL5
  13. Fujifilm X-E1
  14. Canon EOS 60D
  15. Panasonic Lumix DMC-G5
  16. Nikon D300s
  17. Canon EOS 650D
  18. Pentax K-5
  19. Canon EOS 700D
  20. Nikon D5200

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DSLR for beginners


The Canon EOS 350D is a beginner-friendly digital SLR camera (c) Konrad Bieber / pixelio.de

Every beginning is difficult and if you are just getting into the world of photography, it shouldn't necessarily be the digital SLR camera for 3,000 euros. For newbies, we recommend a DSLR with practical additional functions and automatics that help out when taking photos with autofocus and auto ISO.

In general, you should move within a price range of 500 to 600 euros and pay attention to an average resolution of 8 megapixels. Recommended DSLR devices are the Canon models of the EOS series, such as the 350D or 600D, as well as the Nikon D40.

[learn_more caption = "Automatic functions of the DSLR"]

Automatic functions of the DSLR

Beginners with less experience in particular can benefit from the automatic functions of modern digital SLR cameras. Helpful functions improve the image quality and significantly reduce the learning curve. Hobby photographers can also take great photos with the DSLR.

The most important DSLR car functions:
  • Autofocus: Using phase or contrast detection, the DSLR automatically determines the distance between the subject and the lens and thus sets the correct image sharpness in a short time using the motor. The reflex camera mostly works with phase autofocus, with modern systems also using active autofocus systems with infrared and ultrasound.

  • Auto ISO: a digital single lens reflex camera with auto ISO function determines the correct light sensitivity for a picture. Depending on the image and light situation, a different decision is made here and the photographer is saved some work. Nevertheless, you should use the Auto ISO on the DSLR with care, as it can also cause image noise

  • Image stabilizer: the image stabilizer is the practical, built-in solution for all hobby photographers who do not use a camera tripod. Using technical-mechanical means, fluctuations and movements are balanced out so that the image is automatically kept in focus by the DSLR and remains sharp. Of course, this technology also has its limits.

  • Automatic face recognition: the automatic recognition for faces is now used in almost every camera. As the name suggests, the DSLR automatically detects faces in the subject and focuses them.

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Digital SLR camera for advanced users


The price increases with the quality of a DSLR, of course, but if you already have experience and want to take a more serious and professional approach to photography, you should look around in a price segment around 1000 to 1300 euros. A higher resolution of at least 10 megapixels is mandatory here and with more manual settings and options, you will become increasingly master of the image and your digital SLR camera. Canon recommends the EOS 30D or 40D and Nikon offers the D80 in this class.

[learn_more caption = "Digitization: Essentials for advanced users"]

Digitization: essentials for advanced users

As the name suggests, digital SLR cameras make digital pictures that can be easily and quickly transferred to a computer. Here advanced photographers work with Adobe Lightroom or the image processing program Photoshop to edit the image material or to add effects. Depending on the intended end product - as web content, digital photo book or printout - the photo of the DSLR must be processed.

There are some technical options and hardware for this process that make work in the software easier. For example, you can work particularly quickly with a graphics tablet that is operated with an interactive pen and allows more precise lines to be drawn. From a certain level of professionalism, such a sign tablet should be part of the high-quality digital SLR camera.

In addition, the monitor plays an important role in image processing. Color fidelity and temperature, brightness and contrast, if set incorrectly, can quickly convey a completely wrong picture. This is then corrected manually and leads to incorrect printouts. Advanced users of the DSLR should not do without these tools.

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Professional DSLR


Speed, flexibility and most importantly: reliability. A digital SLR camera from the top price range must meet the requirements and everyday life of professionals. They offer lots of manual settings and fine adjustments that enable the photographer to capture every subject optimally and to the best of their ability. A professional DSLR is available from around 3,000 euros, although there are of course no limits to the price.

In return, the buyer also gets a digital single-lens reflex camera with up to 21 megapixels. Whether it is worthwhile for a normal photographer to purchase such a DSLR model is ultimately up to your own feelings and budget. If you are looking for a digital SLR camera of the professional class, take a look at the Canon EOS 1Ds Mark III or Nikon D300.

[learn_more caption = "Professional printers for DSLR photographers"]

Professional printers for DSLR photographers


In professional photography in particular, it is increasingly important not only to shoot and edit pictures, but also to print them out - and in maximum sizes. Precisely for this reason, a maximum resolution and number of megapixels is necessary for high-priced digital SLR cameras. The higher these values, the greater the print can be without any loss of quality in terms of sharpness, color depth or contrast.

Both monitor calibration with professional technology and a dedicated photo printer are essential for perfect printing. In this way, the image material is always displayed exactly and the print result and the screen displays correspond to one another. This makes time-consuming, repeated post-processing obsolete. If you want to take full advantage of the possibilities of the digital reflex camera on a professional level, you cannot avoid this technology.

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Functions of the DSLR in video


This video explains the functionality and possibilities of a DSLR camera once again in a clear and understandable way:

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Digital SLR camera vs. system camera


The system camera has become more and more popular in recent years. Compared to the digital mirror reflex camera, it works without the built-in tilting mirror. Above all, it convinces with its weight and the same image quality, but offers fewer options than the DSLR when it comes to photo accessories.

System and DSLR

    • + Weight
    • + cleaning
    • + Appealing to beginners
    • + speed
    • = picture quality
    • = Additional functions
    • Autofocus
    • equipment
    • No viewfinder
    • Not very interesting for professionals

Digital SLR camera vs. compact camera


The keyword “digital camera” has been on everyone's lips for years. Everyone either has a dedicated digital camera or at least a smartphone, tablet or mobile game console that has a camera. Of course, these solutions offer less quality than the digital SLR camera. In addition, with a few more expensive exceptions, the compact camera offers fewer accessories than the DSLR.

Compact and DSLR

    • + mobility
    • + Uncomplicated operation
    • + price
    • + User friendly
    • = Additional functions
    • no lenses and filters
    • No viewfinder
    • Irrelevant for professionals

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Camera accessories for the DSLR


In addition to the viewfinder and folding mirror, the numerous photo accessories in particular are characteristic of the digital reflex camera. From SIGMA lenses to filters to tripods, flash lights and mounts, the market for DSLR cameras offers a wide range of offers and opportunities to make even more of your own photo.

A macro shot with a digital reflex camera and a suitable lens (c) luise / pixelio.de

DSLR lenses

Some of the most important accessory components of the DSLR are the lenses. They expand or change the field of view of the camera and thus provide interesting effects or extremely high zoom.

In general, you should also consider here before buying:

What I want? What can I? How much can I spend? Similar to buying a digital SLR camera. Not every amateur should upgrade the viewfinder with the most expensive technology. All providers, NIKON, Sony and Canon offer lenses for their cameras.

Essential lenses:

  • Zoom lenses: The zoom speaks for itself: Motifs and objects that are far and even further away are optically zoomed in and can also be photographed razor-sharp with the DSLR at greater distances.

    • Standard zoom: ideal for landscapes, groups, architecture and everyday life

    • Wide angle: an increased angle of incidence of up to 180 degrees captures more of the surroundings and is suitable for spatial, landscape and sports shots

    • Telephoto zoom: Very long focal length for high quality pictures of distant subjects, particularly suitable for stadium pictures or wide landscape photographs

    • Super zoom: Maximum focal length for maximum distance between viewfinder and subject, is suitable for taking pictures of celestial bodies, for example

  • Macro lenses: For the first time, these lenses enable high-resolution images with large scales of up to 1: 9. This enables detailed photographs of flowers or insects.

Filters for the digital reflex camera


If the digital reflex camera with its high image quality and sharpness also offers optimal options for processing in the photo software, not every effect is always possible. Filters are especially useful for color effects and various contrast options. They are placed in front of the lens of the DSLR and, depending on the technology, enable various image components or light effects to be amplified or weakened, which can already be seen in the viewfinder before the picture is taken.

Filters for the DSLR:

  • Polarizing filter: is also called CPL filter and is one of the most essential filters for digital SLR cameras, counteracts strong reflections on reflective surfaces

  • UV filter: Blocks ultraviolet light, which in direct sunlight often causes color distortions in the DSLR

  • Star filter: an effect filter that maps reflections in the form of stars onto light sources in the image

  • Graduated gray filter: a filter for the DSLR that prevents the sky from being too bright

  • Close-up lens filter an alternative for the macro lens, which acts as a magnifying glass and enlarges the subject in the viewfinder and in the picture

External accessories


A tripod for the DSLR pays off in many photo situations (c) BirgitH / pixelio.de

Just as important as lenses and filters are the external photo accessories for the digital SLR camera. This includes all kinds of structures, such as the flash, and of course the photographer's loyal companion: the camera tripod. The flash light provides additional lighting in the location.

While the origins lay in small explosions and ultimately incandescent lamps, today's DSLR flash technology works with energy-saving LEDs. The red-eye effect has also been overcome by new flash systems by briefly pre-flashing and thus anticipating the reflection in the eye.

The tripod for the DSLR


The camera tripod is an absolute must-have accessory for the digital SLR camera for both professionals and amateurs. It stabilizes the DSLR and enables long-term recordings from a fixed position without wobbling or other movements disturbing the image. A distinction is made between the heads of camera tripods.

The ball head enables free movement and quick adjustments and with the three-way head, which integrates all 3 axes separately, the smallest fine adjustments can be made, which offers a lot of leeway, especially in professional work.Hobby photographers should use the ball head and make sure that the stability and weight of the tripod are balanced.

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Digital reflex camera and image processing


Anyone who works with a digital SLR camera - regardless of whether they are a professional photographer or a hobbyist - aims to transfer the images to the computer. Most of them then continue to refine or alienate the images in the image processing program. This software enables the clipping of picture elements, working with different levels, complicated constructions and interesting effects, up to completely new creations and big changes of the original picture material from the digital reflex camera.

The results of the digital reflex camera can be edited in the software (c) Gisela Peter / pixelio.de

A high resolution of the DSLR is particularly important when working with the software, as a larger number of pixels enables more precise work. In principle, however, any digital image can be edited. The most common programs are Adobe Photoshop and Lightroom, as well as free Gimp and Paint.Net

DSLR photography tutorials


The digital reflex camera is predestined for professional work in a wide variety of areas. From beginners to professionals, DSLR photographers are constantly faced with new challenges: product photos, landscape shots, effective photographs, portraits and many more. In order to be prepared for every task, we have explained the most important areas in some photography tutorials for the DSLR.

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