From the example of the sunset picture in installment #1 of this photography basics series, you have learned the importance of taking full control over the exposure on your camera.  Now, it’s time to dig into your camera and learn the three most basic tools available to you in controlling the exposure.

Those tools are shutter speed, aperture, and ISO.  After I explain what each one does, I’ll explain why we need three separate tools to control the brightness or darkness of the photo.


close up photo of an aperture in a camera lens

A small aperture in a camera lens.

The aperture is a small set of blades in the lens that controls how much light will enter the camera.  The blades create a octagonal shape that can be widened (we photogs call it shooting “wide open”), or closed down to a small hole.  Obviously, if you shoot with the aperture wide open, then more light is allowed into the camera than if the aperture is closed down to only allow a tiny hole of light to enter the camera.

So suppose you take a picture that is too bright.  How do you fix it?  Simply choose a smaller aperture.  Simple! Aperture sizes are measured by f-stops.  A high f-stop like f-22 means that the aperture hole is quite small, and a low f-stop like f/3.5 means that the aperture is wide open.

Let’s test your knowledge to make sure you have it down.  If you take a picture and it’s too dark at f/5.6, would you choose a lower f-stop number or a higher one?  Yep!  You’d choose a lower f-stop number, which opens up the aperture to let in more light. The size of the aperture controls more than the brightness or darkness of the picture, though.

The aperture also controls the depth-of-field.  Depth-of-field is how much of the picture is sharp, and how much is blurry.  If you want to take a picture of a person and have the background be blurry, you’d use shallow depth of field.  If you want to take a picture of a sweeping mountain vista, you’d want to use a small aperture size (high f-stop number) so that the entire scene is in sharp focus. If you, like me, are more of a visual learner, then I think this graphic will help solidify the information about aperture.  Take a minute and make sure you understand this info before moving on.

Graphic explanation of the aperture for photography basics learners


Shutter Speed

The shutter is a small “curtain” in the camera that quickly rolls over the image sensor (the digital version of film) and allows light to shine onto the imaging sensor for a fraction of a second. The longer the shutter allows light to shine onto the image sensor, the brighter the picture since more light is gathered.  A darker picture is produced when the shutter moves very quickly and only allows light to touch the imaging sensor for a tiny fraction of a second. The duration that the shutter allows light onto the image sensor is called the shutter speed, and is measured in fractions of a second.  So a shuttedr speed of 1/2 of a second will allow more light to touch the image sensor and will produce a brighter picture than a shutter speed of 1/200 of a second. So if you’re taking a picture an it is too dark, you could use a slower shutter speed to allow the camera to gather more light.

Example picture of motion blur caused by too slow of a shutter speed.

That’s me! Typing away on this article from my studio in Caldwell, Idaho.

Just as the aperture affects the exposure as well as the depth-of field, the shutter affects more than just the exposure.  The shutter speed is also principally responsible for controlling the amount of blur in a picture. If you think about it, it makes sense that the shutter speed controls how much blur is in the picture.

Imagine me sitting here at my computer desk waving to you (you don’t have to imagine very hard if you just look at the picture on the right).If you take a picture of me with a shutter speed of 1/30th of a second, then my hand will have moved in the time that the camera is recording the picture.  To get rid of the blur, you need to increase the shutter speed to around 1/320th of a second.  At this speed, my hand is still moving, but the camera takes the picture so fast that my hand travels only such a small distance that it is not noticeable in the picture.

Graphic explaining the effects of changing the shutter speed




The funny thing about ISO is that it is an acronym, but nobody really knows what it stands for.  It is always just called ISO even though it really stands for International Organization for Standardization.  Every once in a while, you’ll hear an older photographer pronounce it “I-so”, but almost everyone pronounces it “I.S.O.” The ISO controls the exposure by using software in the camera to make it extra sensitive to light.

A high ISO such as ISO 1,600 will produce a brighter picture than a lower ISO such as ISO 100. The drawback to increasing the ISO is that it makes the picture noisier.  Digital noise is apparent when a photo looks grainy. Have you ever taken a picture at night with your cell phone or your pocket camera, and noticed that it looks really grainy?  That is because the camera tried to compensate for the dark scene by choosing a high ISO, which causes more grain.

What constitutes a “high” ISO is constantly changing.  Camera companies are constantly improving the ability of cameras to use high ISOs without as much grain.  A few years ago, only the highest-end pro DSLR cameras could achieve 2,000 ISO, and now even entry-level DSLR cameras can shoot at this level.  Since each camera is different, you would do well to do a few tests with your camera to see how high of an ISO you can shoot at without making the image overly grainy.

Right now, you will commonly find new DSLRs that advertise expandable ISO ranges. To learn more about that, click here.

A graphic explanation of how ISO settings work in basic photography


Putting It All Together

A ram attempting to mate with a ewe bighorn sheep in Yellowstone.

Bighorn sheep in Yellowstone National Park.  Photo by Jim Harmer (Founder of Improve Photography)

I know exactly what you’re thinking: “Why do I need three tools to control the exposure!?!?  Wouldn’t one suffice?”  The answer is no, and I’ll explain why with an example. In January 2012, I took a trip to my favorite place on the planet to take pictures–Yellowstone National Park.  My guide informed us that the bighorn sheep in the park were dying off very quickly due to whooping cough, so I worked hard that week to capture pictures of the last few sheep in that area of the park. Around 9AM on a cloudy day, I found a small group of bighorn sheep and started photographing them with a long 600mm lens.  The early hour and clouded sky made the situation quite dark for shooting.

The lens I was working with (which costs $11,000–don’t they know I’ve gotta send my kids to college?)… Anyway, it had a maximum aperture size of f/4.  So I set my aperture at f/4 to gather as much light as possible.  This also impacted the depth-of field to blur out the rocks behind the bighorn sheep. Next, I set my shutter speed.  I wanted to capture action in the photo, so I set my camera to 1/1000th of a second shutter speed.  I knew that this fast of a shutter speed would prevent any motion blur from the sheep running on the mountain side. Then, I took a picture.  WAAAY too dark!  I couldn’t compromise my shutter speed or aperture, so I knew I needed to use the third player in the exposure triangle–the ISO.

I played around with my ISO and found that if I increased it to ISO 640, it made the picture bright enough to take the picture without making it overly grainy. Yahtzee!  This combination of shutter speed, aperture, and ISO worked out perfectly.  Now can you see why you need to know how to shutter, aperture, AND ISO, and know how to set them independently on your camera?

Click the link below to continue reading this totally free photography basics series of articles, but if you’re more of a visual person and want to see how to set the camera settings for various situations, you should really check out Photography Start.  It’s a video series I did where I walk you through the basics of photography.  People pay $90 for it all the time, but since you found this tutorial, you can get it for just $50 with coupon code BASICS.  Check it out here.  In the videos I’ll SHOW you how to capture great lighting, where to find the best compositions for landscapes, show you how to use a flash, etc.  It’s the best video training I’ve ever put together, and at half the cost… it’s quite the deal.  Check it out here.

In part 3 of the Photo Basics Series, I’m going to teach you how to set these on your camera.

Go to Page 3 of the Tutorial


  1. Jodi Tashman Photography

    Thanks for providing this information. Most websites do an ok job of defining the components and explaining their usage. What they don’t necessarily do is offer a clean, easy understanding of how to put it all together. Your instruction is well-written and easy to follow. Thank you.

  2. Tony

    Thank you very much for this learning article! I have learn a lot from you though im still a beginner ill try to improve more :)

  3. Jason

    I am really liking this series! Thanks so much for putting it together!

    There is one minor error that you may want to fix. It can be found in the last sentence of the first paragraph of the section called “Shutter Speed”

    You wrote: “So if you’re taking a picture *an* it is too dark, you could use a slower shutter speed to allow the camera to gather more light.”

    But you should have written: “So if you’re taking a picture *AND* it is too dark, you could use a slower shutter speed to allow the camera to gather more light.”

    (Sorry. I’m an English minor in college. I’ll let you know if I spot any more. =) )

  4. Roch

    I’m new to the world of photography. I have just bought my first DSLR two weeks ago. I appreciate your articles. Thanks for sharing!

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  6. Senah

    Thank you so much… this make way more sense then some trying to explain…. now I can say I know a little bit more on photography – I used to just snap away and get lucky with the pics

    thank you for this post

  7. Natalie

    Simple and easy to follow, enjoying the learning experience.
    Thank you for making this available.

  8. Burgundy

    Oh my GOSH. Thank the maker for your way with words! You have taught me more in my 30 minutes of reading your photography basics than I have learned in MONTHS of trying to understand it from any other photographer, website or video I have (no knowingly) wasted my time on! Thank YOU!

  9. Lex

    Thanks for this. You explained it in a easy way to understand without trying to sound like you are sophisticated by using big words, like a lot of people do.

  10. Sctt

    Thank you for the visuals! I only noticed them after I had started writing something very similar hahah

  11. carl

    ISO doenst change the “brightness” of an exposure. Changing the ISO requires changes to either shutter speed or aperture to give the exact same EV or “brightness.” The only effect on the picture itself should be increased noise, more depth of field or less camera blur, the EV is the same. The reason dark motifs appear brighter, is that dumb modes in the camera exposure system try to move average brightness to zone 5. This is the main reason for shooting manual, so that a motif can be rendered in the correct zone – i.e. a dark scene might look better shot at the correct zone instead of being artificially moved up to average brightness. If you don’t want to do a bunch of post process, and want to control your images without a bunch of bracketing, you need to get away from matrix metering and take control of exposure by using the zone system previsualization and setting a EV that is appropriate for the motif.

  12. Ria R-B

    This is the clearest, simplest lesson I’ve ever had on how to use my camera! Thank you!!!! You should get paid for this! Seriously.

  13. D.D.

    Albert Einstein said, ““If you can’t explain it simply, you don’t understand it well enough.” You, sir, have a stellar understanding of the art and mechanics of photography.

  14. Kristi

    Your explanations are great and thank you for putting them in terms everyone can understand! Thank you for sharing your expertise with us!

  15. Keithy B.

    “The funny thing about ISO is that it is an acronym, but nobody really knows what it stands for.”

    ISO is not an acronym. See here:

    And the correct pronunciation is EYE-so (you can ask them yourself if you like), though most photographers get it wrong. In my experience, people who deal with ISO in other industries (chemicals, etc) are much more likely to get it right.

    1. Author
      Jim Harmer

      @Keithy, I guess I was being a bit sarcastic. I don’t mean that NOBODY knows what it stands for, but that it’s not common knowledge.

  16. xeronix

    WHAT AN ARTICLE!! this is so far, hands-down the best guide i could possibly find. It has been put very creatively simple that a layman like me could understand every single jargon with ease. I love the graphic examples and they are very immensely helpful. Thank you so much for your outstanding work and time to help people like me new to this exciting journey.

  17. James Dean

    Hi Jim,Great tutorials.I look at a lot of photography information and have lear’nt things that that I

    have not found out about anywhere else, Also your information is so simple and easy to follow.

    Regards Jim downunder.

  18. Brian Pex

    Jim, you are great. I got into photography about a year ago and I was able to pick up very quickly on these above mentioned settings but I don’t get some of the negative picky comments people make. You’re a nice guy who is doing something you love and have passion for and you are sharing it with us. Thanks and keep up great work! I love your podcast so please don’t take too long in between them episodes! I get withdrawals! Thanks!

  19. Monica

    I was very confused initially dat wat those terms actually meant.But after reading your article,things are very clear in my mind.Now i’m pretty confident about taking a perfect shot.

  20. Jonathan Simmons

    Made everything a lot easier but my camera doesn’t have shutter speed. I was told that with my camera, my shutter is my ISO. How can I distinguish between the 2. Are they proportonal?

  21. Nazish Khan

    I have had a DSLR for a while now but could never get my head around ISO, Aperture and Shutter Speed. I read many articles but found them complicated and confusing. But your article has put it so simply, especially with your visual graphics, I have actually u dear stood these three elements.
    So, thank you very much for the article.

  22. Dawn

    For the longest time, I could NOT figure out how to put those three together. I knew what each meant but it was very difficult to figure out how to put them all together. Your article was very helpful. Thank you!

  23. Colin

    Great set of articles you have made a complicated subject easy to understand.
    Thank you.

  24. Udhay

    Thanks for this tutorials. Simple to read, its giving me more interest to read. Photography is a hobby, but used only the automatic mode. I tried to learn from different articles in the past, but it confused me a lot and made to set with the auto mode. Now I am more interested to learn, presently having only a basic SLR from Olympus, giving some good shots only by luck, now I understand why. One clarification, what is focal length in mm and what photographers saying 100 mm lens etc. Are they same ? and how to choose it? Just my guess, the larger the mm, the good image of larger distance ? Can you please explain.

  25. Jasmin

    Thankyou so much as I hv attended few classes but never had a detailed explanation. Your info really helped. Thankyou

  26. rahel

    You are the first blogger (or what ever I should call you) which explained everything so good!! Only by reading this article I am your new fan haha I hope to learn a lot more about my camera with you :) thank you

  27. jovansuper

    Hey!!! Good Day! I recently bought my 1st ever cam with a manual setting which is the Fujifillm Finepix s4000 and I have been spending almost a week just to get the right adjustments. But thanks to your blog, it explained everything in laymans term.. I have a a question though, is my choice of buying this camera model a good choice or not?.. thanks and more power!!

  28. kari bonkoski

    Thank you so much! I take product pictures of my handmade online hat business and cannot seam to get the pictures to not looked washed out or clear. I have searched high and low for a easy to understand step by step on dslr camera settings for my nikon and I also am a visual learner so your step by step instruction was perfect. Thank you!!!

  29. Kay

    I’m confused. I know wide open apeture gives shallow depth which means brighter photo with blurred background. What if I want brighter photo with full depth(sharp everywhere – front and back), is that the 3rd option I play with always last?

    So 1st, play with F stop to know what I want blurred and not blurred.
    Then play with shutter speed so I can decide whether I want motion blur(aka still photo waterfall vs waterfall moving).
    Then iso to see if it is too dark?

    Same sequence for day/night shots? Or do night shots have a trickiness. (Just make sure tripod is used)

    1. David Eller

      ISO is almost always last. If depth of field is your priority then set F-stop first. Shutter speed next and ISO last (full manual mode). This will usually result in using the lowest ISO for the best picture. Selecting the lowest/slowest shutter speed you can live with will allow the lowest ISO which gives you the best quality picture. Most cameras in most of the manual modes lock these three together and force you to change at least one for the correct exposure. Using AV/aperture priority, set the f-stop and then ISO to drive the shutter speed to the desired value.

  30. Kay

    So say its a bright day for a concert outside. I want a bright photo sharp everywhere.

    1. Since I want it sharp I should start at f/18 aperature. But it’ll be so dark though???!

    2. So set shutter speed high so no motion blur. So 1/800.

    So at this point, by your chart, I have 2 dark’s just by trying to get sharpness for field of depth and shutter speed.

    3. Should I brighten with ISO to 1600 or higher to compensate the darkness but get grainy?

    Or lower the ISO to like 800 and..
    .. lower the aperature to like f/5 despite getting background blur and keep everything else same?

    or Should I lower the shutter speed despite maybe getting motion and keep the other settings the same?

    I guess I’m confused as to which one I should pick to lighten or darken since they all lighten and darken.

    I just want a bright sharp all around non motion pic.

  31. David Eller

    Only in the pure “manual” mode will you have to pick all three of these. If you are shooting in most other manual modes (TV; shutter priority, AV; aperture priority) the camera will indicate when all three setting will provide the correct exposure. Like you said, aperture first for a clear depth of field, shutter speed is your next priority but you end up getting it by adjusting ISO. In theses manual modes if you want to brighten the picture more than “normal” then you can adjust your cameras “exposure compensation” to +1 to +2. Most cameras have this option which is really just adding an amount of “F-stop”. In the pure manual mode (“M” on most cameras) the camera doesn’t link these three together and you have to pick each setting. This is really advanced and I recommend you start with AV mode and add exposure compensation. Have fun, Experiment!

  32. Priya Saxena

    Hi Author,

    I brought my first DSLR yesterday and had a little clue about how to change these three controls in it! Your post has done me real good, especially the one where you have woven it all in a story form. Will read more about shooting from this website.


  33. Victor

    Thanks for sharing this article! I have recently bought my first DSLR (canon eos100d). Your clear explanation and the clear examples made it very easy to understand the logic behind the Apperture, Shutter and ISO. I will defitely apply what I have learned here and keep checking future posts. Good work!

  34. Charlene

    thank you so much! I received a Canon Rebel T5 and many, many accessories to go with it for my 40th birthday, and have been finding these articles/lessons very helpful! I did not know where to begin, although I just shoot and have fun. I am determined to learn how to shoot decent pics of mostly my family, pets, daily life, in manual mode!
    I will be reading and rereading lessons 1-3 over and over while taking practice shots, so I can train my brain! Really, great job!!!!

  35. kham

    Thanks for sharing your knowledge to a beginner like me it’s a treasure of informations …/:-)

  36. Amerei

    After waiting for about a year and a half, I finally bought an entry level Nikon d3300 over the weekend. I poured over the camera manual for a day learning “how” to change ISO, aperture and shutter speed but didn’t know “what” values to set them to. Individually, they are easy to understand. Combining them all to produce a decent picture seemed rather difficult to get wrap my head around that during my first field day, I ended up resorting to the auto mode. The fine art I guess is how to mix them all to be able to get a picture I want. The article was very helpful, but even more helpful was the “Putting it all together” section where I got to understand the thought process on how to actually put together some “initial” values and how to correct them later on.

    Overall, this is an insightful and very educational read. The easy and laid back prose was practical and there are no complex fractions (math) and other charts that delude the reader with too much information to handle. Thank you.

  37. Manny Zarate

    I am a newbie at DSLR cameras, so excuse my ignorance :)

    Why would I want to do all these manually when I can use the full auto option? do that means the full auto does not do a great job or not as good as we manually selecting the options of Aperture, Shutter speed and ISO? or is done just for fun and the challenge of doing it manually?

    Should I always shoot in RAW? if yes why, or what other modes should I use instead?

    Thank you and appreciate your input and thank you for such as great article :)


  38. Manju

    I had bought Sony a7 with Sony 28-70 lens. Started learning by self with trial and errors. I found it difficult to understand the terms such as Aperture, shutter speed, iso, etc. After going thru this article many of my doubts are clarified. Yesterday I bought Sony 70-200 f/4 lens !! Thanks a lot !!!

    1. Gopi

      I bought Nikon D710 0 Nikon Nikkor 18-140 mm 1:3.5-5.6 lens and Nikon Speed light SB-910 . I am trying to learn more about this camera processing like shutter speed ISO aperture. Please give me some examples to learn and getting good pictures.

      Thank you


  39. Joy Factor

    Wow! I just a bought a camera and reading the instructions on how to use each one of those tiny buttons is very tiring for me but thanks to you for doing an amazing job for making my life so easier! I am a mountain climber and love to take landscape pictures and will sure try this. Thank You!

  40. Anna

    I always appreciate when someone teaches well. You explained it succinctly and clearly. Thank you!

  41. Lo

    By George… or By Jim… I think I am actually comprehending this Aperture, Shutter Speed and ISO thing finally. You are explaining it very well and the bighorn sheep example was excellent!! Excited for page 3 of the tutorial. PS I really hate the whole f/stop big number is smaller opening/larger number is smaller opening. Really who came up with that! Not logical for me but I will roll with it.

  42. Daemon

    This is super helpful, much more understandable than other articles.

  43. John Rowan

    This has helped me heaps thank you. Easy to read and understand, big thumbs up!!

  44. ishaan

    hy !
    i bought hx400v sony ! but i m nt able to blur the backgroung !
    can u tell me how to focus ?

  45. Khalil Hanna Hraimat

    Thank you so much for posting this article, really loved it and very useful, but still I have a question, do you intend to change the shutter, aperture, and ISO in specific order? If YES please explain.

    1. Jeff Harmon


      I always want the ISO to be the smallest number it can be, so I set it at 100 to start with (unless I can tell from experience the lighting is too low then I will start with 400 or 800). Then I have to decide if my emphasis is stopping motion vs. the depth-of-field. If I want to stop motion I may use shutter priority mode so that I can se the shutter speed and let the camera figure out the aperture. If I want to control the depth-of-field (either making sure everything is in focus or only the subject is in focus and the background is blurry) then I will use aperture priority mode and let the camera set the shutter speed. It just depends what shot you are trying to create.

      Great question, I think I may do a Photo Taco episode on it!

      Jeff Harmon

      1. Khalil Hanna Hraimat

        Thank you Jeff, I think this is you are totally right, instead to handle everything in Manual at once, sometimes when you in rush and you need this shot, you can’t make the precise decision unless you pick the suitable creative mode which suits the moment, as you said, if your interest is in getting the depth of field and focus, then you do this and let the camera do the rest, I’ll start adopt myself in using the creative modes more.

        Yes, I encourage you to do an episode about it, beginners like me will appreciate it too much :) Thanks again pal.


  46. Alicia Poe

    I have been using a digital Nikon L810 but you can’t make very many adjustments with ISO or aperture and nothing with the shutter speed outside of the different modes. So my Dad fished out my Aunts old camera for me to experiment with – it is an old Olympus OM-G film camera. She had 4 lenses (35mm, 50mm, 100-200mm, and a 135 mm) I was wondering if the lenses can be used on a digital camera… the film is cool but I don’t like that I can’t see if I got a good picture or not. Any help with tips on use would also be greatly appriciated it did not have its manual and what I could look up is hard to understand consisting of mostly pictures and very little explination.

  47. Ranul

    Thank you so much for simplifying everything.
    I really had a hard time relating the three elements together.
    Been reading a lot of things and only on your post that I understand them clearly.

  48. Sanjay

    What a fantastic explanation. You are doing a really great job by creating this website which have useful tools and technique necessary for new photographers. There are millions of website on this subject but your explanation skills are best and user friendly. Keep it up.


  49. Yashaswini

    Thankyou so much for the explanation. I couldnt get my head around these basic . I till here its been so simple to understand and surely will help in application.

  50. Liv

    Nice explanation, I’ve read a few things and it’s hard to put the pieces together. This is clear and concise.

  51. Ben Colman

    It is incorrect to say that different apertures or different shutter speeds will cause a darker or lighter picture. Correct exposure is not dependent on one setting. For any given ISO, exposure is determined by a combination of two settings, shutter speed AND aperture.

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