What is a DSLR (Digital SLR)?

DSLR stands for “Digital Single Lens Reflex”. In simple language, DSLR is a digital camera that uses mirrors to direct light from the lens to the viewfinder, which is a hole on the back of the camera that you look through to see what you are taking a picture of.

1) What do DSLR cameras consist of?

Take a look at the following image of an SLR cross section (image courtesy of Wikipedia):

SLR Cross Section
  1. Lens
  2. Reflex mirror
  3. Shutter
  4. Image sensor
  5. Matte focusing screen
  6. Condenser lens
  7. Pentaprism
  8. Eyepiece/Viewfinder

 

2) How do DSLR cameras work?

When you look through the viewfinder on the back of the camera, whatever you see is exactly what you are going to get in the photograph. The scene that you are taking a picture of passes through the lens in a form of light into a reflex mirror (#2) that sits at a 45 degree angle inside the camera chamber, which then forwards the light vertically to an optical element called a “pentaprism” (#7). The pentaprism then converts the vertical light to horizontal by redirecting the light through two separate mirrors, right into the viewfinder (#8).

When you take a picture, the reflex mirror (#2) swings upwards, blocking the vertical pathway and letting the light directly through. Then, the shutter (#3) opens up and the light reaches the image sensor (#4). The shutter (#3) remains open for as long as needed for the image sensor (#4) to record the image, then the shutter (#3) closes and the reflex mirror (#2) drops back to the 45 degree angle to continue redirecting the light into the viewfinder.

Obviously, the process doesn’t stop there. Next, a lot of complicated image processing happens on the camera. The camera processor takes the information from the image sensor, converts it into an appropriate format, then writes it into a memory card. The whole process takes very little time and some professional DSLRs can do this 11 times in one second!

The above is a very simple way to explain how DSLR cameras work.

To read a lot more about DSLRs, check out this great article at Wikipedia.

Comments

  1. 1
    ) Feruza
    March 21, 2010 at 5:47 pm

    Wow! And to think that it all started with me trying to find a new “sambusa” recipe for my Navruz table:) I found so much more than that!
    Thank you so much, Nassim and Lola for creating this wonderful site! It is full of useful information, beautifully and skillfully made, well maintained, and is just pure inspiration for a lot of young families, especially, the once whose roots are so far away from this land, often feeling lonely and isolated, misunderstood, under appreciated, foreign.
    Just look at you two! I don’t even know you guys, but you make me feel proud of where I come from once again!It’s not your “achievements”, or your obvious wellbeing that is stirring these special feelings in my heart, but the way, how you just make everything seem so effortless! You just do what you like, and it’s beautiful! You and your wife are beautiful beautiful human beings, and your children are blessed to have parents like you. This is the way you should live a life-pursuing your dreams, without pretension, whining, expectations.
    It’s also funny how many things in common we have…We’re also a young Uzbek couple with a 3 year old daughter living in the States. I’m a stay at home mom (well, I work from home occasionally), my husband runs his small company. And this year, after years of speculations and pondering, I decided to go back to school this year to learn Photography and Graphic design, putting my International Marketing Degree and many years of experience as a translator on the shelf for a rest. So many doubts, so many things to consider, a young child, growing way to fast, a great loving husband to take care of… How to do it all at once? One step at a time I tell myself. But life is too short, and you’ve got to follow your calling.
    Sorry, I got carried away!:) But, thank you, thank you so much again for being an unforgettable Navruz gift for me this year, a good sign from the Space:)
    Navruzingiz muborak bulsin!
    P.S I know this is not exactly a relevant comment to this particular page, but I just felt like pouring it all out here and now:)
    I wish you guys lived in Oregon, we would love for our daughter to grow up around great Uzbek families like yours!

    • March 24, 2010 at 1:27 am

      Feruza, thank you for visiting our website and dropping a lengthy comment!

      We appreciate your warm words and feedback about our work, we truly appreciate it. Let us know if you happen to visit Colorado, we would love to host you and your family for a dinner.

      Best of luck to you and your family!

      Sincerely,
      Nasim

      • 22
        ) rahul kumar
        December 28, 2010 at 7:01 am

        help me for the basic concepts of photographry…………………..

      • 23
        ) joel
        January 17, 2011 at 9:55 am

        tnx for your very interesting site…hope i follow your steps on photography…..

        • 42
          ) Pankaj
          November 11, 2012 at 10:28 pm

          you rock, great stuff for beginners like me.

  2. 3
    ) salil
    May 6, 2010 at 12:30 am

    woosh ! complicated yet brilliantly articulated..
    Sir, i am a student. I saved my pocket money and took up tuitions to buy a digital camera.. my mind is boggled with the variety n complexity the cameras offer..
    i know u are an extremely professional photographer (your website says it all :)) and its a petty issue for you …. but i ll be highly obliged if you wriggle me out of this issue.. i HAve shortlisted Nikon coolpix S3000. s570, Sony cybershot DSc W320…

    • May 10, 2010 at 12:57 pm

      Salil, honestly speaking, I do not know much about the current point and shoot cameras. I would certainly not recommend Nikon for P&S though…

      Take a look at some of the Panasonic FZ series, specifically the Panasonic FZ-35 – I have some friends that bought it and they are very happy with their purchase.

  3. 5
    ) Xin Chi
    May 27, 2010 at 1:20 am

    Hi Nasim,

    I’ve been thinking about purchasing a d300, but I have a few questions. On Amazon.com they have the regular d300s CMOS body for about $1500 and the d300 DX camera for about $1800. Can you please tell me what the difference is between those two? I am trying to figure out why there is a price difference between them two.

    Thanks!

  4. 7
    ) Jeff
    June 8, 2010 at 12:26 pm

    Hi Nasim, i accidentally found this site and so really happy reading.
    As a beginner I really want to buy a canon Eos Rebel T2i 18.0 MP but upon reading on your site I changed my mind to Nikon. So i was planning to buy this D90 rarther than D5000, because of some features that are present in D90. But this slr is for semi-prof and im a beginner.

    Ive read in one store that they are selling in package deal of D90 which includes 18-105 mm f/3.5- f5.6 DX that is connected to the body, and another additional lense of 70-300 mm f4.5-5.6G ED-IF AF-S VR telephoto lens.
    I want to take pictures more on landscapes, portraits, those with blur and from everyday use…
    So Nasim my question are these?
    1. Is D90 aslo suitable for us as a beginner?
    2. This additional lense in the package deal is worthy to be bought?
    3. What lenses can you advice?
    Your respond is highly appreciated.
    Thanks Nasim for sharing your talent and knowledge with us and more Power! Your really a VERY great help for us beginners.

    • June 11, 2010 at 1:56 pm

      Jeff, I apologize for a late response. The Nikon D90 is a superb camera and it is a world ahead of the Canon T2i.

      1) Yes, D90 is suitable for a beginner.
      2) Absolutely, the Nikon 70-300mm VR is a great telephoto lens.
      3) The above two lenses are great to get you started.

      Currently, the Nikon D90+18-105mm+70-30mm is selling for $1,459.90 (normally it is $1700+), which is an unbelievable price. B&H also has in stock and they can ship it to you tomorrow morning.

      Hope this helps!

  5. 8
    ) jeff
    June 10, 2010 at 9:06 pm

    HI Nasim,
    In addition to the question of mine, upon reading your site again i’ve gained new knowlegde, this two lenses that I was planniing to buy the aperture of both are not far from each other.
    What is the nice picture can be taken in 70-300 mm f4.5-5.6G ED-IF AF-S VR telephoto lens?
    thanks again

    • June 11, 2010 at 2:00 pm

      Jeff, the Nikon 70-300mm is a telephoto lens, which means that it is good for capturing pictures of birds and animals from a distance. The kit lens 18-105mm is good for everyday “general” photography.

      What you might need in addition to these two lenses, is a fast prime lens like the Nikon 50mm f/1.4G, Nikon 50mm f/1.8D or Nikon 35mm f/1.8G. The first one is a little expensive and might be too long of a focal length for the D90, so the 35mm would probably be ideal for you. It is a cheap lens and costs only $200.

      Let me know if you have any questions.

  6. 11
    ) jeff
    June 12, 2010 at 7:26 am

    Hi Nasim thank you for your response, its really a great help for me.
    Ill take your advice and im going to buy them.lol Yeah I think Ill just get this 35mm f 1.8G cause its more cheaper than the others but why is this more cheaper than those two wherein it has a smaller aperture?
    Is this good to to make bokeh? I love your pictures with bokeh its all fantastic.
    This 18-105mm can also make a picture that let the backround blur?

    Ive learned a lot in your site… Knows some terms already.hehehe
    Thanks again and More Power…

    • June 16, 2010 at 10:29 pm

      Jeff, you are most welcome! The 35mm has the same aperture size as the 50mm f/1.8D. The Nikon 50mm f/1.4G has the largest of them all.

      Yes, these lenses are good for bokeh, but the 50mm f/1.4G is the best. The Nikon 18-105mm is not good for bokeh, because it is designed for that and has a rather small aperture size (f/3.5-f/5.6).

      Hope this helps, let me know if you have any other questions.

  7. 13
    ) arun_casio
    July 11, 2010 at 10:21 pm

    sir,
    i am beginner in photography and after dedicating a lot of time trying to gain information regarding DSLR cameras especially frm ur blog, i finally decided to buy NIKON D 3000. i luv D 5000 but don have that much money :-(. it seems u r a great fan of nikon D 5000.. may i know if i buy D3000 can u help me to improve my photography techniques by guiding me to the diff techniques and settings. plz help me and i want u to be mu guru in photography. :-) god bless u :-)

    • July 17, 2010 at 1:46 am

      Arun,

      I would love to help you as much as I can, but I can’t offer to dedicate my time, since I have too many things on my plate. I write articles almost every day and I recommend that you subscribe and ask questions when you have them – I will do my best to respond.

      Sincerely,
      Nasim

      • 15
        ) arun_casio
        July 18, 2010 at 11:52 am

        sir,
        thank u very very much for replying to my blog. 7 days b4 i bought Nikon D3000 and is studying little by little. i do have a lot of query regarding my DSLR. does the camera don click if there is not enough light? and i luv taking photos of sceenery, birds and small animals and species. which type lens i ve to use so that i can get optimum results? nw am using lens type 18-55 VR kit. can u guide me to which type of photos i can take with this type of lens?

        • July 29, 2010 at 2:31 am

          Arun, you can take any types of pictures with the 18-55mm VR lens, except for maybe long range. Use it for landscapes/architecture and portraits, although if you want to have a nice bokeh, you will have to get a separate portrait lens like the Nikon 35mm f/1.8G.

  8. 17
    ) Manu Koshy
    August 3, 2010 at 2:58 pm

    First of all I want to thank you for this wonderful site that you have. I am also a beginner in photography and wanted to do photography for long time. I finally bought a Nikon D3000, also. I would like to learn the basics and then want to upgrade to one of the more expensive camera, like the d300s or d700. Again thanks for the info you provided to all the beginners like us.

    • August 18, 2010 at 1:52 pm

      Manu, you are most welcome! Thanks for visiting our blog!

      • 19
        ) Manu Koshy
        August 18, 2010 at 7:53 pm

        After reading your recomendation. I sold my d3000 and bought a D90. And I love this camera. This one takes much better pic than the d3000. Thanks again for your support.

        • September 1, 2010 at 11:32 pm

          Manu, I’m glad you like the D90 – it is one hell of a camera, much better than the D3000 :)

  9. 21
    ) Jeck Parreno
    December 27, 2010 at 1:50 am

    hi,

    i don’t know nothing about photography and DSLR camera. these tips will be my guide as a beginner.

    thanks

  10. 24
    ) Rajiv
    January 31, 2011 at 9:16 pm

    Hi Nasim

    I am still confused. I am planning to purchase my first DSLR.
    Dont know which one to buy D3000 or D5000 or D90.
    Also which are essential lens kits to buy. I enjoy doing every day photography and also some distance based.

    please help me decide and thanks for your help.

    regards
    Rajiv

    • February 25, 2011 at 5:26 pm

      Rajiv, see my DSLR Purchase Advice.

      • 26
        ) Rajiv
        February 26, 2011 at 4:37 am

        Thanks Nasim, This was pretty useful ! Purchased Nikon D3100..
        Started clicking pics…but still loads to learn…need to figure control on Aperture, Shutter speeds and ISO..

        Any more tips ??

        Regards

  11. 27
    ) anish
    May 26, 2011 at 12:50 pm

    Hi Nasim,

    I’m Anish and i’m pretty new to serious photography eventhough i have used sony cybershoot cameras in auto mode in the past.
    I’m an engineer by profession and i have a great passion for phtography. Honestly i dont know how to manipulate the photos using adobe or any other software. What i do normally is frame the picture and shoot. I dont know anything other than this.

    But i always gets frustrated by the low light performance of the cybershoot camera and i failed to capture of the wonderful moments in life because of the sluggish camera. So i decided to go for a better camera.

    For the last couple of months i was going through various sites inclusind kenrockwell’s to understand photography. Since i dont know much about photography many of the things (such as aperture priority, shutter priority etc) mentioned in those sites gone over my head.

    Can you recommend a camera to me. I read a lot about nikon d3100 and nikon d5100. The latter is new to the market and has the better sensor( thats what the reviews say) and i’m NOT really concerned about videography since i wont do it. The nikon d5100 allows metering(I REALLY DONT KNOW HOW TO DO IT BUT I WILL LEARN IT) and HDR( I have seen some photos in flickr and HDR is a great technique i feel)

    Which one of those cameras will be easier to learn. The price differrence between d5100 and d3100 is around $125( Rs 6000 in india). Can you please recommend one.

    And i always felt sad about the 3x zoom of my cybershoot, i want bit more than 3x zoom i.e. >18-55mm.
    Is it wiser option to go for 18-105 rather than 18-55? Please advice

    Please let me know your suggestions whether nikon d5100 or nikon d3100 and 18-105 0r nikon 18-55 as the kit lens.

    In india the nikon d5100 is chaper compared to than in US the same is applicable for d3100

    Thanks in advance. Hope you will reply. Have a great day. God bless

    Anish

  12. 28
    ) anish
    June 10, 2011 at 12:50 pm

    Hi Nasim,

    Thanks a lot for responding. I bought the camera.

    Thanks
    Anish

  13. 29
    ) Josh
    June 21, 2011 at 9:22 am

    Good day, I’m surprised and grateful for this blog, congratulations.
    I’m sure the comments and information that are on their website, my photo experience will be unforgettable.
    2 days ago bought my first camera relex, and although I care for my budget, also I have a chance now to spend a little more if necessary.

    Buy a Nikon D3100, plus a 50-200 mm lens.

    I will study to dedicate mainly to the photo studio, weddings, birthdays, and perhaps take a taste for landscapes, sports stadiums, and famous cities.

    My questions are:

    1. D3100 was a good choice to start.
    2.lente 50-200 mm is good for the exterior and landscape, sports stadiums, and famous cities.
    3.The her blog comment that the 70-300 mm lens is very good. You better change the 50-200 mm lens, or stay with it.
    4. Other options can be a d90 and a D5100, I have some days for the return and exchange with the seller. This is necessary if I’m starting to change the D3100?, If so, what do you recommend for studio shot photos of people and landscapes?
    5.Quiero buy the lights, backgrounds, and more. What is the basic kit to mount a study I need.

    Thanks for your attention, I hope your kind comments.

    Josh (geek trainee)

  14. 30
    ) brijesh
    November 11, 2011 at 7:04 am

    thanx a lot for this basic and compulsory information.

  15. 31
    ) roger
    November 18, 2011 at 12:51 pm

    hi,

    i have nikon d90, please advise which me which lens i will choose between nikon 50-200mm and tamron 70-300 mm, and why, thanks in advance, and more power to you.

  16. 32
    ) Akif Musafir
    December 5, 2011 at 6:01 am

    Hi,
    I’m from Afghanistan and I love photography i worked more then 2 years to buy a Reflex I’ve got D550 and i’m very Happy with quality of my camera and it’s a fine camera but I’ve got a lot problems with my Lens (18-55mm Canon) I’ve got like 500 $ I just don’t want to buy some thing that i can’t use or not necessary for me because I’m a beginner but I hope you help me out with my problem i’m sending this message with a lots of hope because here in Afghanistan we don’t have any freelance photographer or a teacher to teach me.
    Thanks

    • 35
      ) Akef
      April 19, 2012 at 3:47 am

      Hi can you Delete my comments from your website.

      Thank you in advance

      • 39
        ) Akef
        July 7, 2012 at 10:20 am

        Please Delete My Comment from Your website.
        Please

  17. 33
    ) Farhan
    March 10, 2012 at 4:50 am

    Dear Mr Nasim
    Hi
    I am in love with your site since I came to know about a couple of weeks. You had been explaining in such a simple manner that even an abnitio like me can understand it easily. I was planning to buy a DSLR and decided almost Nikon D7000. Later going through the reviews on D800 I started to change my mind and thinking of to start the digital photography once for all from a Fx format. I will appreciate if you could spare some time to recommend me the camera either D7000 or D800. In addition, some lenses for a beginer and mainly interested in family functions, portraits, landscape and some natural life close ups. I can complete my bag in stages.
    My sincere prayers for you

  18. 34
    ) Kishore
    April 19, 2012 at 2:16 am

    Hello Mr. Nasim,

    Your site is just amazing! Very helpful! I just recently bought one Nikon D90, and also a couple of lenses (Nikon DX 35mm 1.8 G and 70-300mm telephoto VR lens). Would you please recommend some very basic settings of the camera for taking just regular home pictures? Any other advise will be highly appreciated.
    Thanks in advance.

  19. 36
    ) Diana
    June 6, 2012 at 7:39 pm

    Hello :)

    Your site if very helpful to the beginners! I really want to learn about photography but sadly, I don’t have a professional camera and it was late when I saw that you had a camera giveaway :( Anyway, will get updates from you soon on when is your next giveaway so I can join and I can achieve one of my dreams- to be a great photogapher.

    THANK YOU! :)

  20. 37
    ) dheeraj
    June 11, 2012 at 6:27 am

    This is an awesome piece of information for the beginners like me.. please post some more information on various techniques and methods of photography

  21. June 23, 2012 at 12:22 pm

    Hello : I am in the catagory “amateur” and just about to purchase my first time DSLR camera. I enjoy photography so much and wish to bring myself one step higher. An shamelessly put my website among the pros just to ensure me to improve to be like them! ..or at least closer…lol. Why did you recommend T1i instead of T3i? I thought of purchasing T3i. Are they big different of these two cameras? Please let me know. Your article is so helpful. Thank you so very much.

  22. 40
    ) Benny
    July 26, 2012 at 5:46 am

    The article reminded me my class 10 subject on camera/lenses. Thanks for the great and simple writeup which helped again to recall what exactly I will be doing with my camera. Thanks Nasim.

  23. 41
    ) Rijo
    October 20, 2012 at 2:31 pm

    I am planning to buy a Nikon D3200 with 18-105mm VR lense. Any advices or suggetions guys??

  24. 43
    ) alok
    December 5, 2012 at 8:24 pm

    Your website is very informative. I want to thank you for all the basic things that you’ve explained in detail. Please tell me which one of the Nikon D5200 and Canon 60D is a better dslr?

  25. 44
    ) Vov
    December 20, 2012 at 7:41 am

    Thanks for the clear explanations, they help a lot!

  26. 45
    ) Umar Sharif
    December 24, 2012 at 5:54 am

    Dear Mr.Nazim,
    I just bought Sony a-57 DSLT with f/3.5-f/5.6, 18-55 SAM. Generally quite happy with the range of additional featured they had put in this camera including panorama and 3d photos but when coming to still photography i am not fully convinced with the quality of image i am getting. Mostly i intend to to landscape photography. Is my lens not good enough, if yes, which one i should go for?

  27. 46
    ) seun ogundimu
    February 6, 2013 at 4:33 am

    I am a beginner that just bought a sony a-57 with f/3.5-f5.6,18-55SAM and extra lens f4.5-5.6(75-3000).
    pls what are the apature to use when doing still photographs and landscape?

  28. 47
    ) noor ul amin khan
    May 30, 2013 at 12:55 pm

    hello dear nasim how are you ?

    nasim bro i want to buy nikon d3100 can you please tell me about it how it ‘s i am a beginner

    thanks and warm regards
    noor ul amin khan

  29. 48
    ) deepak
    July 27, 2013 at 9:32 pm

    awesome explaination of how DSLR works..easy to undstnd..can u suggest me sm books abt photography..Im amateur,photography is my hobby..but i really want to b good at it..no professional purpose only for my satisfaction..

  30. 49
    ) Snaffer
    November 7, 2013 at 5:53 pm

    Great explanation and it help me a lot as a beginner to understand what actually DSLR is.

    Thanks dude!

  31. 50
    ) Ramesh
    December 19, 2013 at 8:29 am

    Can it get any better than this ?? Great stuff. Keep it up. What do you think of D7100 vs 70D ? Any suggestions ?

  32. December 26, 2013 at 4:55 am

    Awsome explanation in a simple manner that is in easily understandable manner……..Thank you and good work…………

  33. December 26, 2013 at 5:27 am

    Could u suggest which is advaisable 1) full frame is or APS-C (Nikon – D3200) for a beginner in photography..?

  34. 53
    ) Kenny DSouza
    January 7, 2014 at 2:39 am

    Hi. I have been using a point n shoot camera for a very long time and decided to go in for a DSLR. I opted for the Canon EOS 1100D with the standard 18-55mm lens. I need help in making the most of this camera and also learning a few tips and tricks. I love landscape, wildlife and sports photography. Portraits also to a certain extent. Please help!!! Thank you!!!

  35. Profile photo of Mjay
    54
    ) Mjay
    March 11, 2014 at 6:28 pm

    I accedentally find this site when i try to find ways on how to improve my photography… I love reading all of it…. It is really a big help for me… Thank you so much… more power…God bless…

  36. 55
    ) shivam
    May 18, 2014 at 5:16 am

    What u think about Sony A58 Y ?

    Should i buy this for nature photography ..plzz help me

  37. 56
    ) shivam
    May 18, 2014 at 5:17 am

    Plz reply me soon
    If u got some time plzz call me on +919824303662

  38. 57
    ) Elben
    June 5, 2014 at 6:56 am

    Thanks.

  39. 58
    ) Piyush
    July 2, 2014 at 12:15 am

    Hi,
    I am considering a Canon EOS M (Mirror-less), it doesn’t have a viewfinder which is annoying at first but the LCD Screen Display is responsive enough, My question is, How good is a Mirror-less camera if compared with a DSLR ?

  40. 59
    ) charlotte
    July 17, 2014 at 2:21 am

    Very nice article. Made things so simple for newbies like me.
    Well done! Thanks a lot! :)

  41. 60
    ) Rajive
    July 27, 2014 at 8:55 am

    Grate article. I am new to photography. I am planing to buy a DSLR camera. This will me to choose good one.

  42. 61
    ) Lana
    July 30, 2014 at 1:39 am

    Excellent article – I appreciate that it is simplified. I like to know the logics in why something happens and this assisted greatly

  43. 62
    ) Jayant phulkar
    August 3, 2014 at 4:39 am

    Sir i have D 90 ,recently i purchased nikkor 300mm AF-S F/4
    kindly suggest me ur article to do photography with this lens

  44. 63
    ) rahi
    August 5, 2014 at 10:28 pm

    Very good article…

  45. 64
    ) syed naqhib bareed
    August 31, 2014 at 12:02 am

    It was really helpful for a beginner like me… thank you:-)

  46. Profile photo of Summer
    65
    ) Summer
    September 6, 2014 at 12:13 am

    I love this website, thank you so much for it! (:

  47. 66
    ) Ajit Kurup
    September 10, 2014 at 8:59 pm

    Hi Nasim,

    This site is very useful. I think a wide range of topics have been covered and as far as using and understanding the various functions in a dslr this site is complete.

  48. 67
    ) sunil mani
    September 11, 2014 at 1:46 am

    Thank you for you Great Tutorial

  49. 68
    ) Abdul
    September 16, 2014 at 4:24 am

    We are a team of video production company. Looking forward to your guidelines on photography.
    Thanks

  50. 69
    ) Riek
    September 19, 2014 at 9:49 am

    In one word-EXCELLENT!!!!!!A buttery smooth understanding of such a complicated topic! Nice job Nasim. Really Brilliantly You served the subject for a novice like me. A far clear concept do I posses now; thanks to You.

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