Photography Basics – Understanding Exposure, Aperture, Shutter Speed, and ISO [Part I]

Did You Find This Article Useful? Why Not Share It Then?Share on Google+Tweet about this on TwitterShare on Facebook

Many photographers think that understanding Exposure is the toughest aspect in photography. Several people may shy away from a DSLR because they have to understand some of the alien terms like Aperture, Shutter Speed, ISO, etc.

The reality is that understanding these key concepts is easy and fun.

It requires a bit more time and patience to understand it in depth. Aperture, Shutter Speed and ISO are the basic building blocks of photography. If you understand how each of them work together to get an optimal exposure, you will enjoy your photography to the fullest.

To make the camera see the way we see is the most difficult aspect in photography. But, as we understand more about the exposure, we will be able to make the camera see what we want it to see.

I will write series of articles about the core concepts of Exposure called Aperture, Shutter Speed and ISO to make it easy to understand.

Want to learn more about photography? Sign up now to get a FREE eBook. [thrive_2step id=’2953′]Download Beginner’s Guide to Photography.Beginners Guide to Photography. Free eBook on Photography for Beginners. Best Photography Free eBook. Written by Prathap[/thrive_2step]

We all know that we see the world through our eyes with the help of light. When there is absolutely no light, then we do not see anything. In a way, our eyes are exposed to light to form a picture in our brain through which we perceive/understand our world.

A photograph is made when the lens (or eyes) bends the light onto the sensor (or brain) to form a photograph (or picture).

Exposure

Exposure, in simple terms, means how much time the camera sensor is exposed to the light to make a photograph.

The amount of light passing through the lens opening (Aperture) for a specified duration of time (Shutter Speed) for which the camera sensor is open is called the Exposure.

Exposure is essentially a combination of Aperture, Shutter Speed, and ISO. To keep the matters simple, let us concentrate only on Aperture and Shutter Speed and keep the ISO for later articles.

Here is a simple equation for exposure:

Exposure = Aperture + Shutter Speed + ISO

Next articles in this series discuss each core concepts Aperture, Shutter Speed, and ISO in detail.

A properly exposed photograph will contain proper color information and all the details that are present in the actual scene.

A photographer’s life is so much easier in today’s digital world due to histograms. You can see if the exposure is correct or not by looking at the histograms. However, the knowledge of exposure will enable you to achieve optimum exposures to fulfill the artistic needs and to achieve creative results.

Underexposure

If the amount of light passing through the lens opening for a duration of time when the camera sensor is open is less than optimal, then it is called underexposure.

The underexposed photograph will look darker than the real scene.

Underexposed photographs usually lack details in the shadow regions resulting in the crushed blacks. The histogram of such photographs, show the distribution towards the left most side with some clipped blacks.

Nature Photography Simplified. Underexposed image of Great Egret standing on the fence.

This photograph of a Great Egret is severely underexposed throwing the background very dark. We see crushed blacks in several parts of the photograph. The histogram shows the clipped blacks indicating an underexposed photograph

Overexposure 

If the amount of light passing through the lens opening for a duration of time when the camera sensor is open is more than optimal, then it is called overexposure.

The overexposed photograph will look brighter than the real scene.

Overexposed photographs usually lack details in the highlight regions resulting in the washed out details. The histogram of such photographs, show the distribution towards the right most side with some clipped whites.

Nature Photography Simplified. Over exposed image of the Chipmunk.

This photograph of a Chipmunk is overexposed as well as underexposed portions. Upper right half of the background is completely overexposed showing no details. Histogram shows the clipped highlights in the right hand side of the graph

Optimal Exposure 

If the photograph looks closer to reality, then the exposure is optimal. As photographers we may decide to either expose and develop the photograph to depict the reality or to depict our artistic vision.

King-Fisher-Proper-Distribution-Histogram

The Belted Kingfisher photograph has the optimum exposure. This is also indicated with the nice distribution of the histogram without any clipping on either end

Exposure Range or Dynamic Range 

Every camera possesses an exposure range or dynamic range that depicts its capability to collect the light information. This light information is later converted to a suitable form to represent a photograph.

In simple terms, an exposure or dynamic range is nothing but the lowest and the highest exposure a camera can record in a given scene. Or the darkest and the brightest details a camera can record in a given scene.

Dynamic range may vary from camera to camera based on how much light the sensor can hold. The larger the sensor and its pixel size, greater the dynamic range, since it can capture higher amount of light.

For example, consider a camera that has 5-stops dynamic range. Suppose, the main subject needs an aperture of f/11 (with constant shutter speed of 1/125th of a second), then everything in the scene that requires an aperture of f/5.6 to f/22 will be represented properly.

Anything below f/5.6 will result in pure black and anything above f/22 will result in pure white.

Photography Basics. Understanding Exposure, Aperture, Shutter Speed, ISO

Note: The Shutter Speed and ISO are assumed to be constant

Let us understand the dynamic range using Shutter Speed instead. Suppose, the main subject needs a shutter speed of 1/125th of a second (with constant aperture say f/11), then everything in the scene that requires a shutter speed of 1/30th to 1/500th of a second will be represented properly.

Anything below 1/30th of a second will result in pure black and anything above 1/500th of a second will result in pure white.

Photography Basics. Understanding Exposure, Aperture, Shutter Speed, ISO

Note: The Aperture and ISO are assumed to be constant

I have considered a 2-stop lower and 2-stop higher than the normal for the sake of explanation. In reality, the film cameras (or negatives) usually tend to preserve more details in the brighter regions than the darker regions. The digital cameras tend to preserve more details in the darker regions than the brighter regions.

Want to learn more simple photography tips like this? [thrive_2step id=’2953′]Download Beginner’s Guide to Photography.Beginners Guide to Photography. Free eBook on Photography for Beginners. Best Photography Free eBook. Written by Prathap[/thrive_2step]

In Part-II, we discuss about Acheiving Optimal Exposure for various scenes like Low-key, High-key, HDR, and Normal scenes.

Nature Photography Simplified. Understanding Exposure, Aperture, Shutter Speed, ISO eBook. Written by Prathap.Buy the Printable version of Understanding Exposure (9-Part Series) for $1.99 USD only! 

 

 

Did You Find This Article Useful? Why Not Share It Then?Share on Google+Tweet about this on TwitterShare on Facebook

,

36 Responses to Photography Basics – Understanding Exposure, Aperture, Shutter Speed, and ISO [Part I]

  1. Gerrie Malan March 16, 2014 at 12:39 am #

    Thank you Prathap. By far the best article I have seen on the topic.

    • Prathap March 16, 2014 at 1:52 am #

      Thanks a lot Gerrie!

  2. Jorge March 16, 2014 at 5:30 am #

    Thanks for your articles, you made them very easy to understand. Congratulations for your very beatiful pictures.

    • Prathap March 16, 2014 at 6:56 am #

      Thank you for you kind words Jorge 🙂

  3. Prabhakaran D. March 16, 2014 at 8:44 am #

    Thank you for this article on basic concepts. I must appreciate your lucid style without any intimidating jargon. Looking forward to have more from you.

    • Prathap March 16, 2014 at 9:53 am #

      Thank you for your encouraging words Prabhakaran. I try my level best to make my articles valuable.Thanks for all the support!

  4. Barry Southon March 16, 2014 at 10:05 am #

    Prathap

    Very informative without the overload over technical terminology.

    The willingness to share your expertise in the format you do is a great credit. Long may you continue with success.

    Thank you

    • Prathap March 16, 2014 at 11:32 am #

      Thank you very much for your wishes and encouraging words Barry Southon 🙂

  5. Paul Powers March 16, 2014 at 12:22 pm #

    Just to add a bit to this discussion: sometimes you want to deliberately overexpose or underexpose for effect. I suggest that your underexposed example is a perfect example of this. A more balanced histogram might result in the complete elimination of detail in the feathers. I suggest that the underexposed background is what makes this picture stunning. Just my .02.

    • Prathap March 16, 2014 at 8:41 pm #

      Perfect Paul! That was the exact reason of underexposure in the Great Egret photograph 🙂
      Thank you!

  6. dhamodaran March 17, 2014 at 11:04 am #

    Enlightening

  7. S.S.Shah March 26, 2014 at 12:43 am #

    Great. No need to attend any photography class. Down to details. Thanks.

    • Prathap March 28, 2014 at 5:23 am #

      Thank you very much! Shah.

  8. Ashok K April 8, 2014 at 7:48 am #

    Quote “Exposure, in simple terms, means how much time the camera sensor is exposed to the light to make a photograph.”

    I would call this definition more “shutter speed’ than exposure. Exposure is the dosage (or quantity) of light. Right exposure (technically) is the one which records maximum tones. It need not be artistically the best though!

    • Prathap April 27, 2014 at 12:20 am #

      Dear Ashok…I agree that it sounds close to Shutter Speed definition. I think the subsequent sentence has the definition of exposure: “The amount of light passing through the lens opening (Aperture) for a specified duration of time (Shutter Speed) for which the camera sensor is open is called the Exposure.” I hope you agree.
      As you rightly said, the right exposure is the one which records the maximum tones. Thanks!

  9. Mayukh June 16, 2014 at 3:34 am #

    Dear Prathap,

    I have a D60 model and would like to upgrade. My primary interest is bird and flower photography.

    Would you please provide some basic inputs for choosing a model? moreover in this article you have talked in length about dynamic range and its effect on the exposure.

    Does camera manufacturer provides the dynamic range w.r.t f stops in their manual or brochure. As far as my D60 is concerned, Nikon didnt provide any information on that.

    Thanks.

    Mayukh

    • Prathap June 16, 2014 at 4:42 am #

      Dear Mayukh, I think D60 is a pretty good model. I used it for 4 years. I would recommend you to invest in better lens instead of changing the Camera if money is a concern.
      If you are starting off on bird photography, I would recommend you to buy 80-400mm VR if possible or 70-300mm VR.
      For flower photography, you could either choose to go with 50mm f/1.8 prime lens (very inexpensive) or 60mm macro lens. Remember that macro photography is completely a different medium wherein you would try to photograph just a tiny bit of a flower (most of the times).
      If you are still left out with money and want to upgrade for the Camera body, you might want to consider Nikon D7100 (I own it now), which is really good for most photographic needs.

      I guess you might not have information on the Dynamic Range of the Camera in manual. You will get complete information in DXO website. For instance, here is the link for Nikon D7100 http://www.dxomark.com/Cameras/Nikon/D7100—Measurements.

      I hope this helps. Good Luck!

  10. Mayukh June 16, 2014 at 5:34 am #

    Dear Prathap,

    Thanks for your prompt response and the detail.

    I own a Nikon 70-300 mm VR which is capable of rendering good images in standard lighting condition.

    I am facing problem with focusing in AF-C mode with my D60 and the limited AF points also adds up.

    Moreover I have observed that most of the times, although my exposure meters shows the correct reading and even after applying “exp comp”, the picture comes out dark.

    I dont know whether I am applying the wrong technique or there is something wrong with my D60.

    Would be happy to clear my doubts in a workshop conducted by you in Delhi in near future.

    Thanks,

    Mayukh

    • Prathap June 16, 2014 at 10:51 am #

      Dear Mayukh, I realized later that you already have 70-300mm VR. That’s a wonderful lens.
      If your photographs are coming out dark, easiest way to figure out the problem is to check the histogram. If it is towards the left, then add more exposure compensation (+ve) and see if that changes. Also try using AF-C mode with a normal scene to check if you are getting the right exposure. Try composing a scene with evenly distributed lighting and use average metering mode with AF-C mode. For normal scene with lot of mid-tones, you should get properly exposed photograph. I hope this helps.
      I would definitely love to conduct workshop in Delhi. Hopefully I get enough inquiries on this from Delhi so that I can plan for it 🙂

      • Mayukh June 17, 2014 at 1:53 am #

        Thanks a lot Prathap for the tip.

        Hope you get enough enquiry from Delhi to conduct a workshop soon 🙂

  11. Parthiban June 16, 2014 at 10:24 pm #

    Thank you for the tips which are easier to be understood. Some professionals expect us to understand all the jargons. Thank you again..

    • Prathap June 17, 2014 at 1:34 am #

      You are most welcome Parthiban 🙂

  12. Mayukh June 30, 2014 at 3:24 am #

    Dear Prathap,

    First of all thanks for clearing my doubts.

    I have started to take pictures in .raw format and would like to do PP for correcting WB/ sharpness etc.

    Would you please help me w.r.t software to be used for PP?

    Should i go for Adobe Raw or Lightroom?

    Thanks.

    Mayukh

    • Prathap July 1, 2014 at 10:01 am #

      Dear Mayukh, That’s great to know! Switching to RAW format is the most important step.
      You can either use Adobe RAW or Lightroom. I have only used Lightroom so far. I have heard many saying they are pretty much similar. I would recommend you to start with either of this and start using them. Just make sure to take it easy. It requires lot of time and effort to get the final output that is pleasing. You will get it for sure one day! Good Luck!

      • Mayukh July 2, 2014 at 7:25 am #

        Dear Prathap,

        I will be going for Lightroom.

        I have one query. Are the display unit of laptop running on Windows OS calibrated w.r.t color? I have heard that Macbook’s comes in pre calibrated form.

        I had those desktop for which i had to install Adobe Calibrator for color management.

        Looking forward to your inputs.

        • Prathap July 7, 2014 at 1:06 am #

          Dear Mayukh, I do not have much idea about calibration of monitors. Last week I was talking to a Photo printer who said it should be done by the professionals so that you get the right output. However, if you are not printing the photographs, I don’t think you need a high-end calibration. Because, even if you have a calibrated monitor, people watching your photographs may not have their monitor calibrated!
          If you happen to use Adobe calibrator may be you could share some inputs with our readers.

  13. Sumanto February 13, 2015 at 7:42 pm #

    Dear Mr. Pratap,

    By Mistake or with good deal I Bought Canon EOS 600 D, after getting that i had got interest in Photography as that become my next hobbies, but had less know about photo shot and all can you suggest me some basic book or website where i can get some knowledge and make my skill sharp by practicing more. As truly say your blogs are helping me a lot as learned Many think from it and will practice this Sunday.

    • Prathap February 15, 2015 at 9:20 am #

      Dear Sumanto, that’s great! The more you shoot the more you will like it. Keep photographing as much as you can. The best photography websites to improve your knowledge are http://digital-photography-school.com/ and https://photographylife.com. I think the best photography book to really get the grove of photography is “The Art of Photography: An Approach to Personal Expression by Bruce Barnbaum.
      I hope this helps.

  14. suresh raut June 2, 2015 at 5:26 pm #

    Ex lent explanation. Dear friend. I would like buy this art cal.give or detail I will trainer money to or account.

    • Prathap June 4, 2015 at 2:39 pm #

      Hi Suresh, I have sent the details to your mail. Please check and reply. Thanks!

  15. Suresh Raut June 11, 2015 at 5:32 pm #

    I have not received e-book on post processing and understanding exposure sir.

    • Prathap June 11, 2015 at 9:33 pm #

      Hi Suresh, i have sent it to you twice. Please check your mail.

  16. M L Raju March 1, 2017 at 7:42 am #

    I am an amateur photographer and presently own Nikon D40 with 50mm prime lens, 18-55 kit lens and 55-200 zoon lens. I want to buy a new camera and zeroed on Nikon D5300 to improve my skills. Kindly suggest whether I can go for it or D7100 is best option in that range. I love landscape and bird photography.

  17. Girish Deshpande September 9, 2017 at 11:05 pm #

    Prathap,

    Thanks a lot.
    You have made it very simple to explain this topic – exposure.
    Very much helpful to all amateur’s like me,

Leave a Reply