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ISO Camera Setting

ISO Camera Setting: What is it?

Understanding ISO

I admit, I Googled ISO earlier to see if Wikipedia could explain this better than me, and frankly, I don’t think it can. Let me take a stab at it. The lower the ISO, the less light comes in and the deeper the color saturation. The higher the ISO, the more light comes in and the more grain will appear in the photo.  Here are some examples. If I am shooting in broad daylight, I keep my ISO between 100 and 200. If I come into a dark house where I do not want to use flash, I turn up my ISO to the next possible setting that will let enough light in to allow me to use a fast enough shutter speed.

This first photo was taken indoors with window light, the ISO is 500, because it was still somewhat dim inside the room.

Bride and groom in field - ISO Camera Setting

This final photo was taken with an ISO of 1600. It was night time, indoors, and without changing the ISO I would have had to set the shutter speed so low that they would have been blurry. You can see a slight bit of graininess in the photo because of the high ISO.

Groom lifting bride - ISO Camera SettingHere is an exercise; Put your camera in aperture priority mode, set the aperture to the lowest possible number.

Remember, this will let the most light in, since it is opening wider.

Now find a room in your house that is dimly lit, one that you would ordinarily use a flash in. Raise up your ISO and take the picture. Are you able to get the shot?

Phew!! That is so much information to take in, are any of you still with me? If you are still reading, thank you!! Ok, so now you have the information. Your assignment this week is to take two photos, one in Automatic mode, and the other either changing the aperture, changing the shutter speed or changing the ISO to make the photo different, better, then the one taken in Auto.

Here are some tips:

  1. Do you hate that flashy look of photos indoors? Turn the flash off, lower your aperture and raise your ISO. You shouldn’t need a flash.
  2. Want to tell a story with your photo? Turn your aperture all the way down (lots of people refer to this as shooting wide open) and blur out some element of the photo, ie, a baby with a big sibling blurry but in the background.
  3. Shooting sports? Set shutter speed faster and your subject suddenly becomes sharp!
  4. It helps to take three or four pictures, each with different settings, so you can get a feel for how each setting will change your photo.

If you’re ready for more, let’s move on!

NEXT STEP: Shutter Speed Settings

Previous articleWhat is ISO?
Next articleWhat is Shutter Speed?


  1. Actually the Matt and Bill explanations worked for me. The radio analogy is perfect. Especially is you called it “tube amplification” of a radio signal. The louder you get the more noise you get. When you get that volume up to 6 or 7 you are in full blown distortion! Actually the analogy is almost perfect as the chemicals used in higher ISO films are “amplifying” the data collection of the shutter and aperture!

  2. You could just say that ISO comes from chemical films and it is a unit of sensitivity. And this is transfered to sensors so now means how sensitive is the sensor.
    Keep it simple.

  3. I enjoy the lessons but for some reason I am unable to see the example pictures. I have tried Safairi and Internet Explorer.

  4. Thank you for such a good and easy to understand information. I have a question, after shooting on higher ISO how to remove grain without getting a soft look.
    Thank you so much

  5. hi i have had great time learning….. but i am still unable to blurr my pictures…. with high iso in the limid room….. and with low aperture…. please precise

  6. I love the simplicity of the terms and illustrations in this lesson. I didn’t even need to take down notes.

  7. I’m a note taking kind of guy so I am actualy supprised by the number of things that I can just read and it sticks bcause you nearly spell it out for those who are doing the course. Great material; I absolutely love this course. This section made perfect sense. Even down to the photos used as examples.

  8. I just went into a dark room (blacked out might I add) took a photo of a black and white picture of Marilyn Monroe, a tall bulb flower and a light brown and dark brown scarf using the directions above. I tell you that is the best picture I have ever snapped and I’ve snapped a lot of great photos. Thank you for this course. ( On manual, Iso 1600, 1/4 f16 I used a flash and it is beautiful. I took another photo with no flash indoors no light coming in and the person is begging me to give them that photo. I am in tears about what I have learned#happy tears.
    Thanks a million

  9. A trick I learned for ISO was to use the letters to say, Is Sun On? And then I was able to determine which one to use.

  10. Thank you SO MUCH for this website! I’ve read and reread the information, and feel that it is very well explained for us “newbies” at photography. I’ve played around with the settings on my Canon Rebel T2i, and never really understood what it was that I was doing. I’ve taken great sport shots, great outdoor photos, and this site helped me understand the fundamentals. Again, thank you very much for this website! You are in my favorites so I can refer back to at anytime!! Highly recommended!!!

  11. I am using a casio e-z1000 camera and every shot that I take has a red cast all ove the photo. why?

    Regards. david Fuchs

  12. “Why do some people have to complicate a perfectly good explanation. BILL and MATT, while you obviously have lots of experience and understanding of ISO, some people struggle with your explanations. This site is for beginners who are struggling with the pro – terminology of photography.”

    Steve – while I understand why you find this hard you also have to realize that what Bill and Matt are saying is right and what was described here in this lesson wasn’t quite right. You can’t say he’s simplifying it for us when he’s simply not 100% correct!

    Thank you Bill and Matt – I appreciate your explanations!

  13. Awesome simple explanation. I am a REAL beginner and need the very simplest explanations. Thanks for your free advice!

  14. This website is the best one for teaching about photography, it’s a life saver. I wanted to really understand my DSLR and I was struggling with remembering some of the finer details of aperture and shutters speed. Thanks to your course, I can now say that I understand it perfectly. So thank you so much.

  15. I just bought the Nikon D7000. So far I LUV it!! I would however like to understand it more and take better pictures as I know this camera is capable of doing so. I went from a cheap camera to the Nikon for the following reasons, I have 3 smaill children.. 2 of them are in Hockey and Baseball. I wanted to capture wayyy better sports pictures as well as them doing other everyday things such as, swimming, playing outside, sitting on the couch etc. As well as take picture of the wildlife, sunsets, landscapes etc. I just want to take some really good pictures!! HOWEVER…. I’m kinda scared to play with the settings too much as Im not sure I could get them back to where they are… I did buy this camera to take better pictures… just a little nervous to take that big step and play around with my camera so to speak. Can you please help me do this!! Thanx a bunch, Amanda 🙂

  16. I am so glad i found your website, as a beginner just starting out i havn’t got round to doing a photography course and this site has explained some technical stuff to me which has made it so much more simpler to understand i thank you loads! i shall now take my tripod and my camera for a spin now i know what im doing =]

  17. i am confused about putting your camera in aperture priority mode. I have a canon rebel xti. How do i put it in that mode?

  18. Thank you so much Carie for writing this article. Your “assignment” to take a picture in auto mode and one with a setting tweaked was really a light bulb moment for me. I spent about 20 minutes taking pictures in a bunch of different settings so I could see what the results look like. Hands on learning is so great!

    And thanks to the other commentors who gave more technical explanations of ISO. Knowing what it meant back in the days of real film helps me a lot. The AM radio explanation helped me too.

    If I’m having a hard time understanding something, I really like having different analogies or explanations to choose from. To quote C.S. Lewis “They are only meant to help, and if they do not help you can drop them.” 🙂 Take what helps you and don’t worry about the rest.

  19. The way the author explained, whether it wasn’t as accurate as how the (obviously) professional photographers previously commented, taught me how to set the correct ISO settings in my digicam. Prior to reading this article… this ISO thing is greek to me. Thanks very much!

  20. Great explanation Matt and Bill. I think it’s better to write it exactly as it is, even if it’s a bit more complicated, than try to make it too simple but incorrect (as the author of the original article).
    In the vanilla film days we had only shutter speed and aperture to limit the amount of light which will reach the film (iso of the film was set), now with digital we can keep the time and f-stop same and just adjust the iso to get different exposures. Bit more complicated but much easier once properly understood.

  21. My son is in a band and when I try to take good pictures of them on stage, I get better pictures of the crowd instead of the band.
    What am I doing wrong?

  22. The easiest way to understand the ISO even for me as non speaking English person. Well done and thank you for making it easy to understand!

  23. Thanks to all you guys who complimented my understanding of this stuff! Im in uni at the moment with a lecturer who can’t explain anything in a way which is logical, but I can definitely put the pieces together from what all of you said…and i definitely understand and appreciate the analogies and scientific ‘backing’ of the concepts explained here. So thanks…and Mike, I do so wish you would be kind enough to explain apertures here as well,but I guess I will have to go to google again and find another forum! All the best 🙂

  24. If Bill and Matt’s explanation is too hard to comprehend, perhaps another way of looking at it might help.

    My stab at ISO: I think of ISO as it was in the olden days, when we had actual physical film cartridges. If you buy a film with a higher ISO, then the film is more sensitive. A lower ISO is less sensitive.
    The shutter speed determines how long the film gets to “see” the world.
    A lower ISO, which is a less sensitive film, needs to see the world longer in order to record it.
    But the results are better because it gets more time to make the chemical reactions on the film when the film is exposed to the world’s light, and you get a nicer, more accurate, less grainy picture.
    Now a higher ISO. This is a more sensitive film. It does not need to see the world for very long to record it. Hence, the shutter speed needs to be faster.
    The result is that subjects appear less blurry for moving subjects, because the shutter is open for less time, and the film is recording the world in less time.
    The end picture tends to less accurate. The chemical reactions are faster because of the higher sensitivity. You get more grain as a result.
    Now, chemical reactions and the digital chip are very similar in a way. The chip has millions of little photo cells. Each cell is a counter that counts from 0 and up. The more light each cell gets, the faster it counts.
    That depends on the ISO level.
    A lower ISO makes the cell count slower.
    A higher ISO makes the cell count faster – but with less accuracy.

    I have no idea if what I’m saying is useful here or if this audience is with me still… I’ll go on.

    About shutter speed.
    Shutter speed is expressed often in 1 over x, eg. 1/200, which is 1 200th of a second which is 0.005 seconds. 1/200 is faster (shorter, quicker) than 1/100, because 1/200 is one out of 200, and 1/100 is one out of 100, or 0.005 vs 0.010 seconds. Many commonly say that 1/200 is higher than 1/100, because they’re referring to the 200 number, which mathematically is backwards, but that’s just what people call it, you get used to it. I think of “higher” in this case as the shutter flicking open and close faster, with more force (kind of), hence more, but in reality is shorter and a lower exposure time.
    So, 1/80 is about as “low” as you want to go taking pictures of people (in my opinion).
    For pets or toddlers running around (same thing 😉 you want a “higher” setting. 1/250, say. 250 is higher than 80, but in actuality 1/80 is a higher number than 1/250, but people refer to 1/250 as a higher setting than 1/80. Backwards, but why not.

    Wait till you try to wrap your head around apertures…

  25. I took a picture in a dim room on auto, then I took the same picture after lowering the aperture and increasing the ISO and the difference is astounding!

  26. Hi to everybody. I think Bill’s explanation of ISO is great. It is very easy-remembered, simple, even enjoyful.. 🙂 His metaphor between iso and am radio always will stay on my mind… Many thanks to Bill for that unique metaphor.. 🙂

  27. Nicely said Steve!!
    I have been doing photography for years and now my daughter is interested. Your explaination is the one I’d choice (between our progessionals Matt & Bill)to help her understand ISO and the shutter speed.
    Thank you for making what we take for granite make since.

  28. I am getting into a new camera.. and dont really know what to buy yet.. I am in limbo on buying a automatic and a slr.. can you tell me what should look for if i am buying a slr.. and auto matc.. camera and thanks Bill for explaining better for me to understand it..

  29. Why do some people have to complicate a perfectly good explanation. BILL and MATT, while you obviously have lots of experience and understanding of ISO, some people struggle with your explanations. This site is for beginners who are struggling with the pro – terminology of photography.

    I have read thousands of books on photography and I find that they are all full of pro – terminology which is not necessary for beginners to understand. I think this site explains the steps very well and with the understanding level which a beginner needs and can understand. While you both have given the correct PRO – TERMINOLOGY, this site has given the steps required to get to the level of producing images just like you can, but without all that useless, might aswell be chinese, terminology you have tried to confuse everyone with.

    Why not just stick to your pro – terminology books and websites and leave this one for the beginners !!

  30. I have some issues with your description of ISO. The ISO has nothing to do with the amount of light coming in. It has to do with the amount of light necessary to create an image. The higher the ISO, the lower the amount of light necessary to create the imagem, and visa versa.

    Turning up the ISO is like turning up the volume on an AM radio. The signal gets louder, but so does the noise. If a station is strong and close, you don’t have to have the volume up very high to get nice clear intellegible reception. If it is a weak station and a long way away, you need to turn up the volume a long way and you can begin to hear what is being broadcase, but you also get to hear static, other stations, etc.

    Exactly the same thing happens with a camera. Nice bright light and low ISO gives clean, crisp, saturated, low noise images. Dim light and high ISO, gives flat, grainy images.

    Modern digital cameras have all sorts of techniques for dealing low light; some are better than others, but they are all quite remarkable.

  31. “The lower the ISO, the less light comes in and the deeper the color saturation. The higher the ISO, the more light comes in and the more grain will appear in the photo.”

    This is sort of confusing. I think you mean the lower the ISO the less exposure will result from a given amount of light. ISO doesn’t affect the amount of light entering the camera. It determines the degree of light sensitivity of the sensor. The lower the ISO the more light is required to get a particular level of exposure. The higher the ISO the less light is required to get a particular level of exposure. Each doubling or halving of the ISO is a stop, or a doubling or halving of the amount of exposure. So ISO 200 requires half the light as ISO 100 and twice the light as ISO 400.

    While saturation may be slightly effected by ISO, it’s much, much more effected by other things, such as the brightness of midtones or how the photo is processed. With the Canon DSLRs I’m using I don’t notice a significant decrease in saturation at the highest ISOs. I think most photographers would notice lowered dynamic range due to high ISO before saturation.

  32. Wow. I’m so glad I found this site. This time, I REALLY GET IT!. You made it so simple. (Just saved you to my favorites!)



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