Understanding ISO, Aperture and Shutter Speed


Thank you so much for the support that you have shown towards the first post of the Photography Series. Your emails and comments on Understand and Play with Light are much appreciated and I hope I have answered all your queries.

Today, we will talk about three important elements that play a vital role in making a picture. It’s a long post with lots of information and details to talk about. If you are new to this, it might take some time to understand and grasp it. When I started clicking in Manual mode, I read these details again and again for months to figure it out and I am still reading, still learning.

The three key elements that work as a chemical process to create an image are ISO, Aperture and Shutter Speed

I will start by explaining each one of them and then we will see how they are connected to each other and how we can create a balance.

ISO: It stands for International Organization of Standardization. Inside your digital camera, there is a component called ‘image sensor’ which basically collects the available light and creates an image. ISO measures the sensitivity of the ‘image sensor’ and accordingly reacts to the available light. ISO ranges from 100 – 6400 and can go even beyond depending on how advanced your camera is.

In the below set of photos, I kept changing the ISO but the rest of settings were not changed. This would give you an understanding of how the image sensor reacted to the light.

In the example below, I changed the shutter speed to get a similar end result even though it was shot with a different ISO. When we discuss shutter speed later, we will see how it works but right now, concentrate on how the picture that was shot with ISO 3200 looks grainy and has noise in the background unlike the one photographed with ISO 400 which is smoother and detailed.

The lower the ISO, the lesser the sensitivity. The higher the ISO, the more the sensitivity and hence, more noise or grain.

In a bright daylight I usually stick to ISO 100 or 200 and when I click at night or in a very dark place, I have to increase the ISO to maximum, if required. While there are some who don’t like noise, there are some who would add noise while post processing. It’s an individual’s choice.

Aperture: Every lens has an opening through which light travels to the image sensor. The size of the opening is referred to as Aperture and it determines the amount of light that enters your camera image sensor.

It works exactly like our eyes! Lets go back to the science chapter where we learnt that for our eyes to see clearly light needs to reach the retina through the pupil, which is the tiny black spot in the center of the iris. In this case, retina would be your ‘image sensor’ and the pupil would be the ‘lens-diaphragm-opening’

Whenever there is a bright light, we tend to shrink our eyes so that we don’t get blinded by it and whenever there is less light, we tend to expand our eyes so that we can see better. In similar manner, we need to adjust the aperture on the lens opening to make sure we have just the right amount of light entering.

Aperture is measured in f/stops or f/number e.g. f/1.4, f/1.8, f/2 etc. There is a lot of math and calculation involved in why and how these numbers got created. Honestly speaking, it’s too much math for my tiny brain; hence I just follow this thumb rule.

The bigger the lens diameter opening, the smaller the f/stop should be. So, if your f/stop is at 1.4 you will have maximum light entering the camera image sensor while at f/22 you will have least amount of light entering the camera image sensor.

Aperture also helps creating a depth a field in your photo. Depth of field (DOF) means how much of area in your photo is in focus. It depends on the focusing distance.

Larger or Wider DOF would mean that most of the area in an image is in focus and for doing that you have to click in higher f/stop number. Shallow or Narrow DOF means only certain part of the image is in focus creating a blurry or fuzzy background, which can be created by clicking in lower f/ stop number.

In the below example, notice the gradual transition as I increased the f /stop.

Shutter Speed: It is the amount of time the shutter stays open for the light to fall on the image sensor to create an image. Remember, inside your camera, it’s dark. It needs light to capture an image and light doesn’t automatically enter inside the camera. Once you set the f/stop and ISO, you have decided the amount of light and the sensitivity of the light; you have to now allow the light to travel to the image sensor by pressing the shutter button.

Shutter speed is measured in seconds or fraction of a second like 1/50, 1/60, 1/80 etc.  The higher the denominator number, the lesser time it gets for light to enter and hence creating a faster shutter speed. The lower the denominator, the more time the shutter stays open and more light enters in, thereby slowing the shutter speed.

Shutter speed is connected with the focal length of the lens. In daylight shooting, a 50mm lens would probably require a shutter speed of 1/60 and with a 200mm lens you would have to shoot at a 1/250-shutter speed.  This is not a rule and it will differ depending on the ISO and f/stop. We will discuss how to balance these a little later.

When I am photographing still life, portrait, landscape I generally stay within a particular range of 1/ 60 sec to about 1/200 (approximately) and that is normal for any existing light situation.

When there is low light, or when I want to photograph a motion, I slower the shutter speed allowing it enough time to capture the available light. During such situation a tripod is must or else the camera will shake creating a blurry image.  Slower the shutter speed means lowering the denominator.

In the below example I used a lower shutter speed so that I could capture the movement.

Camera Setting { f/3.2, ISO: 100, 1/8 sec shutter speed}

On the other hand, if you wish to freeze a motion, like photographing playing kids, or surfers on the ocean, you would need to use a faster shutter speed.

In the below example I tried capturing the flour falling on the bowl, trying to freeze the action unlike in the previous photo where I captured the motion

Camera Setting { f/2.8, ISO: 3200 at 1/1000 sec shutter speed}

Balancing the three elements: In case you dozed off in between, let’s do a quick recap!

  • Image sensor is the object inside your camera that creates a picture and the sensitivity of the light that falls on the image sensor is determined by ISO.
  • The lens opening that allows the light to fall on the image sensor is called aperture and is measured in f/stop.
  • And finally, shutter speed determines how long the image sensor should be exposed to light before it ‘clicks’ the image.

Finding the balance is important to get the exposure you are looking for. Let us look at it through some examples.

This is the set up I used and that’s where I take all my photos. It’s a tiny area next to my kitchen but I love the space because of the two well-lit windows. This way, I get both side light and back light.

Example 1: Grapes

It was a sunny day. I pinned a thin white cloth on both the window blinds thereby diffusing the light. I started with ISO 200. My plan was to focus on the grapes and have a blurry background. So, I set the f/stop at f/1.8 and then, I started to look at the viewfinder of the camera to see how the exposure and light looks. The shutter speed was at 1/50sec, which made it too bright and so. I increased the shutter speed to 1/60sec and it gave me the lighting, the exposure and the depth that I wanted.

Camera Setting {f/1.8, ISO: 200 at 1/60 sec shutter speed}

Example 2: Corn

I wanted an over the top shot and so I removed the table and kept the board on the floor next to the window. I started with f/2.8 because I wanted most of the corn to be visible. As i changed the lens diameter from 1.8 (in previous shot) to 2.8, it automatically reduced the amount of light that could enter the image sensor.  It looked little dark and so, I increased the ISO to 400. After looking through the viewfinder of the camera, it still looked underexposed and hence I lowered the shutter speed to 1/50 sec and I was happy.

I didn’t use any reflector and that created a nice shadow on the right side of the frame.

camera setting {f/2.8, ISO: 400 at 1/50 sec shutter speed}

Example 3: Splashing Water

This was a tough and messy shot! I wanted to freeze the motion and like I said before, in order to do that we would need to click at a much faster shutter speed. I used only sidelight in this case. Since I knew I was going to use a fast shutter speed, I had to increase the ISO so that enough light goes in at the quickest amount of time. Finally, I photographed it at ISO 3200, f/ 3.2 at 1/1000 sec. I am still experimenting with these kinds of shots, trying out different setting but for now, I am satisfied with this.

Camera Setting {f/3.2 , ISO: 3200 at 1/1000sec shutter speed}

Here is a very interesting diagram on Exposure Triangle that I found in Flickr. It is very useful to understand the balance.

It will not be easy to remember all these terms if you are reading it for the first time. You will have to read it again and again, read more articles on the internet, see youtube videos and then slowly you’ll get used to the concept. You have to practice and practice a lot! Hope this was useful and if you have any questions, you know how to contact me! 

Next up: We will talk about white balance, metering and more on camera settings.

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Rosa says:

A wonderful post! The pictures are terrific. You are really talented.



Shinta says:

Fantastic post ! loving this series

Arch says:

God bless you Kankana ! I think I will take print outs of your photo-tutorial and stick it up all over the place – I really grapple with these techie terms, but love the way you’ve explained it. Your photography is simply amazing – the last pic is like WOW !!

Namitha says:

Very well done,great post K 🙂 All the pictures are terrific too. Am bookmarking this and the exposure triangle.Thank you !

wow, wow, wow a gorgeous post with such sound advice. That last snap shot OMG.

Aunt Clara says:

You have a way with words. Now I will have somewhere to send people to when I am asked about photography questions (I am not very good at explaining myself without taking long meandering detours through hyper-technical stuff). Two minutes into it people end up asking “What the hell is a strobe” and lose interest. 🙂

Good job, and lovely pictures!

Divya says:

Very informative post. Love the last pic!

Rathai says:

You deserve a standing ovation for this post. I have across many posts about photography on other blogs but none as detailed as yours. I really appreciate that you have went all the way to show and explain what you mean. Needless to say, the pictures are all breathtaking.

Krittika says:

This is an awesome post.. Look forward to reading your entire series.

sreelu says:

What an excellent post Kankana, it’s one thing learning and another thing teaching and sharing. Really appreciate your effort.
Oh and gorgeous pictures too

Kiran says:

Amazing post, Kankana! Thanks for sharing all of this wonderful photography tips 🙂

Nandita says:

Stunning post with equally stunning photography!!! Just awesome 🙂

This is an amazing post Kankana. You explain the settings so well! keep the series going. It definitely helps budding photogs!

Saguna says:

Read this on the train home from my photography course and it actually clarified things a lot and gave me lovely visual examples. Super post- you’re a great teacher! I ‘ll be looking out for the rest in the series, thank you for all your help…

Such an informative post, K. Love every bit of you, and will come back for reference.

I meant *it*, not you. Okay, you too.

Another amazing and informative post Kankana!!! Your examples are fantastic at demonstrating each point. You are a wonderful teacher. I especially love that shot of the flour. Beautiful!!

Question: The freezing motions when did you shoot both? During the day?

Kankana says:

Thanks Shulie for dropping by and for the RT in twitter 🙂 To answer your question, all my photos are in day light as I do not have studio light. The set up I showed above, is the same set up I used, except I kept a black board to block the back light. While post processing it, I reduced the saturation a lot which is why it looks kinda ‘sepia’ mode.

Such a great resource, I’m so glad you posted this. Your photos are gorgeous and I’m bookmarking this for future reference!

Usha says:

Awesome post, Kankana! You explained the three most important elements of photography very well. I like your photographs. I also tried the splash in my apartment and yeah, it was a messy job! My splash is not as beautiful as yours but I was thrilled I captured something. I think even I used ISO 3200 & do nOt remember the shutter speed. It was a a very big number. Looking forward to your next post on photography.

Kankana says:

Hi Usha, Thank you so much for dropping by 🙂 I am so glad you tried! Did you try in continuous clicks ? Cause it cannot be captured in single shot .. too tough!

usha says:

I set the camera to shoot continuously but it did not work. So I had to do it in single shot. It was a little challenging to capture it in a single shot. Later that night, I learned something new about my new camera. Unlike in my old one, in the new camera I have to press & hold the shutter release button for few seconds for the camera to shoot continuously. I learned something new about my camera that day 🙂 I was meaning to try it again but the mess & cleanup after the photo shoot is daunting and stopping me from trying it again. 🙂

Sonia says:

I would just say a BIG Thank You for everything! 🙂

Shumaila says:

Kankana what a beautifully illustrated informative post.

What a wonderful explanation, you made it so easy, thanks a lot.

Excellent photographs! And a highly commendable effort to explain the concept. Kudos on that!… just a point, you might want to have a post discussing the relative science between ISO and f-stop, to better discuss the effect of low light on photography. Because if shot in yellow light, some of your tips might be perceived otherwise, because people who follow it would not be applying it right. Also, one other key is to talk about effect of White balance on a photo.

Excellent photos!! Loved your photo idea on ISO and shutter speed concepts.

Kankana says:

Thank you Kiran for dropping by and leaving your notes. I plan to discuss about all these in next post. I didn’t wanted to cover everything in one post. Plus, I had mentioned in the first post of the series that I would be talking mostly and mainly about day light photography. Having said that, I agree with your point and will try to cover how to shoot in yellow light in the next post of the series. Thanks once again 🙂

Ananda Rajashekar says:

Babes, i couldn’t stop myself stopping here, very informative post! Thanks for sorting it the way we could absorb it easily and put them action. Loved the fstop, with the images ( i have never come across this kind of post anywhere). You are a shining star! I miss seeing you gorgeous pictures 🙂

Kankana says:

Babes .. so happy to see you here 🙂 Thank you so much and I am so glad you liked it! And you should know I am missing your gorgeous pictures too.

Hi….Thanks for such a very informative post.

In the grapes shot, where do you keep the focus, on the side of the image or the centre? I am not sure if focus is the right term, what I mean is the small rectangle on the viewinder that goes green when focus is achieved. Does the placement of this rectangle determine which part of the pic is in focus, while aperture determines how much is in focus?


Kankana says:

Hi Indu, this is very good question and I was about to cover it in the next post of the series 🙂 Now that rectangle you mentioned, yes that needs to placed in the area where you wish to focus and that rectangle can be moved around. So, I moved slightly at the center bottom so that I could focus on the stems along with grapes around it. And you are right.. that rectangle determines where you want to focus and aperture determines how wide or narrow you wish to focus. If you see the photos of the pastas on top .. you will see how the depth or focus changes and gets wider as I keep increasing the f/stop. Hope this helps 🙂

Thanks Kankana…Looking forward to the next one….

athena says:

excellent post… wish I would’ve had you help me when I started years ago. I’m sure there are many out there who appreciate this and are benefitting immensely from your knowledge 🙂

Maureen says:

I’m in awe of your talent. I’ve always left my ISO on automatic as that’s what my last instructor advised us to do. I’m going to have a play with it tomorrow. 🙂 Thanks heaps.

Pia says:

What a superbly explained article, kankana! This obviously took a LOT of planning! Well done, you 🙂

nags says:

i am sure a lot of people are going to find this super useful. the amount of work that’s gone into it totally shows 🙂

Shabs says:

Thank you so much Kankana , that was really helpful . I am always ogling your photographs .

Kankana, thank you again and again for these helpful posts. Definitely bookmarking this one – read more than once and as you have said that one needs to keep on reading. One thing, your posts are very helpful, written in easy words for a layman like me.

The flour shots – stunning!

Another treasure to my food photography tips folder! Amazing clicks, appreciate o all the handwork gone into making these blog posts, Kankana.

Jacqueline says:

A well written and informative post Kankana. It is so clear you know this subject inside and out. Thanks for being generous enough to share your photography knowledge 🙂

Spandana says:

Very useful post, just like the previous one. Loved all the pics, esp the flour and the juice pics.

Abi says:

Hi, your explanation is very simple & detail. you’ve succeeded in the water splashing photo. I absolutely love it. Also I hv tried with Ison 400 before, however photos have resulted with noise. How to get clear photos? Your simple explanation encourages me to try to shoot in manual mode. Also in your next post I would like u to explain the histogram. tnx

Kankana says:

Thank you Abi! I am not sure why you getting noise when clicked in ISO 400. May be, you could email me (kankana-at-playfulcooking-dot-com) a photo mentioning the Exif data and we can discuss from there. As for histogram, yes I do want to cover it but not planning for the next post. There are few other settings required to be understood before we move to histogram 🙂

ray says:

This a wonderful and very helpful post! You are really an amazing photographer. Thank you very much, Kankana! 🙂

This is such an informative post…sharing knowledge is such a good deed ..u are awesome !!!
I have always admired your photos…
Thanks again

wow! Breathtaking photos and I learned so much from just reading this. I need to get some better equipment i think. Speaking of, I am going to be getting a new camera here shortly. I have a nikon already- what do you suggest

U have really made it easy to understands the different elements of photography… Kan u have really come a long way, I am following ur foot step…
I am loving the water splash picture…

I cannot thank you enough for your tutorial series. I love how you write in simple words so my small brain can take it. I read some books but I really love that you summarize important part so clearly!! I cannot wait for next series. And hopefully you will continue this series with many food photography topics after your photography tutorials (basically please don’t stop teaching us!! haha). 🙂

Kankana says:

Nami, you are such a sweet heart 🙂 I too hope that the learning and sharing doesn’t stop ever! I received your query and would respond back by tomorrow for sure.

rebecca says:

wow your a pro will bookmark and one day in future as kids grow will look into it -) hugs

Deepa says:

You have explained the exact details that I was looking for though I have a basic camera now but this is going to help me in future…Breathtaking pictures….The flour jar clicks are looking straight out of some food magazine…

Debjani says:

Kankana, thank you for taking the time to prepare this for us. It is very well done. Do you see yourself teaching photography in he future, someday? I do. I hope you do.

Kankana says:

Debjani.. jani nah ki bolbo 🙂 If I ever reach at that level, it would be a dream coming true 🙂

mjskit says:

What a great tutorial! Thank you for taking the time to simplify and illustrate! Love your examples and ALL of your photography!

Tanvi says:

Fantastic post! You really simplify some difficult concepts. Thank you for making this series!

Reshmi says:

Loved your post. Truly informative!

Tes says:

Amazing Amazing! All I can say here is amazing!!! Thanks for such a helpful and informative post 🙂

Vishakha says:

At the risk of sounding cliché, I’d like to applaud you for the knowledge you are sharing on this platform. I am sure the knowledge you got from one post, took a lot of time and practice for you to build. To share, is a virtue!:)
I am not & don’t consider myself an artist of any sort and probably that is why, I struggle a bit with composing shots – esp food photography. If you can talk about it in one of your posts, it would be very helpful. Thanks 🙂

Kankana says:

Thanks Vishakha 🙂 I have that too in my list but it will come a little later in the series! For now I can say that visiting food photographer’s blog and portfolio helped me to get inspired and learn in the process. Read Plate to Pixel by Helene. That helped me a lot too.

This is great. I am on the learning curve myself with photography. So much to learn, but I think practice still makes perfect.

Anamika says:

Kankana,a BIG THANK YOU for this post and the series, it is extremely helpful and very well explained too. Amazing photographs, I need to read this post more than once and start implementing, hope to learn more from your series.

lovely post Kankana beautiful pictures, really enjoyed
I am following your tweets 🙂 keep in touch now that there is no foodbuzz

Sihi says:

Beautiful, stunning and absolutely brilliant! You rock, girl!


dassana says:

Fab post & fab pics Kankana. Even when i started with manual mode, i read at least thrice to understand all these elements.

Regarding the meaning of ISO – International Organization of Standardization… When i first read in a book, i laughed. Being a quality analyst in quality we have something like ISO and have to adhere to its principles and objectives. ISO precisely means that – International Organization of Standardization. I wonder why they did not change the definition in photography to something else.

prachi says:

loved,loved this post. I have read quiet a lot of posts on f stops and shutter speeds, but this is the first time I really understood. You have explained beautifully and the photographs are totally awesome!!!
thanks kankana and keep the posts coming!!


I like the way you describe, understandable and easy to digest! you are phenomenal Kan and I speechless. Thank you for being so kind and i always enjoy to read your series of photography tutorial.

Brook says:

Thank you so much for this post. The pictures are gorgeous and you have managed to convey some very intimidating information (to a photo newby) concisely. This will obviously take quite bit of practice and patience!

Maja says:

Kankana, such an amazing and inspiring post! Few months ago I bought dslr camera, so this post is everything what I need! Thanks dear!

Monique says:

Fabulous photos..hope to reread and understand:) Thank you!

I loved your post. I am so new to photography but I am loving it. I get my photos accepted regularly but I know they are very amateurish (is that a word?) and I am constantly learning. I am grateful for this post and will be following you. Cheers, Tara

Jenbeans says:

REALLY useful site! Can’t wait to try out all the stuff you taught us, thanks so much!!!!

This is fantastic, thanks.

BTW You are welcome to join in my monthly food blogger event THE SOUP KITCHEN, here for entry details and current theme. New theme each month. All bloggers are welcome, hope to see you participate soon.

Adriana says:

A very much needed post, thank you! The pictures are stunning and all the explanations make everything seem so easy:) Can’t wait to experiment with these 3 elements.

nipponnin says:

Thank you for the wonderful post. It was fun to see the differences with each shutter speed. Your pictures are really fantastic!

Anamika says:

I am back on this post again to re read it 🙂 , i have already started applying what you shared out here about balancing the three elements while clicking, I am so happy coz the way you made this so simple and easily understandable Kankana, however a lot more to learn and way to go but for the time being I am happy trying my hands on this… thank you, waiting for next one 🙂

Kankana says:

I am so glad it’s helping. Yes, it does take a lot of practice and I am no expert either. but love working around these settings 🙂

BongMom says:

Awesome post. I am going to share it on my FB page if it is ok with you. You deserve a standing ovation for the last shot and I am probably going to print this and tape it at eyeview

Kankana says:

Thank you so much for dropping by 🙂 Please go ahead and share, it would be an honor!

najla says:

I came here through Bong Mom…and wow what a treat I found.
Many a times when I have tried to use the manual mode I have performed miserably…now I have the courage to try again..bookmarking your page.

Manasi says:

Thank you so much for this WONDERFUL post. There is so much for me to learn and improve upon.

Sangeetha says:

Very useful n informative post. I recently started taking pictures in manual mode n this well explained post on the three main elements really helpful…very beautiful pics n i would love to try a splash shot 🙂 yours is awesome!! Great Work n looking forward for your future posts on photography!!
i would like to know about white balance n awaiting for your next post…Thanks!

Somdatta says:

You are truly blessed. Not only you are a great writer, cook and a photographer, you are bighearted enough to share your knowledge with others. My parents always say that a great way to increase your knowledge is to share it. You are a very good example of that 🙂 May God bless you! Cheers !!! – from a new fan 🙂

Kankana says:

Thank you Som Datta for dropping by and for your lovely words 🙂 Nice to meet you!

Karen says:

This is a great post, very helpful and put together in such an easy format. Thank you so much for sharing it!

such a wonderful tutorial Kankana! I’ve always admired your photos, they are perfect, and hopefully one day I’ll get to be at least half as good as you are

Amy says:

I found this post via pinterest and must say these are the most helpful camera tips I have come across. Thank you for sharing and making it easy to understand. I found this so much more helpful than my manual book and feel more confident with using my camera in manual mode. Thanks!

roz says:

Thank you so much! How kind and generous of you to share this information chock full of knowledge with us. It is so helpful!

Vinnie says:

I am a complete newbie with food and photography… but after reading your posts, everything made sense! Thanks so much for this, it definitely is a big help… I hope I get to read more from you and learn more eventually… Made sure to bookmark your site for easy reference. Thanks alot!

Naveen Reddy says:

It is so clearly explained a fresher like me to understand… Keep up the good work.