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What is ISO?

Last Updated on July 19, 2022 by Devaun Lennox

ISO is shorthand for International Standard Organization, which is the organization responsible for setting standards across all camera manufacturers. Long story short, they standardized light sensitivity so that all cameras (for the most part) over the last 40 years are made to react to light similarly. And that’s really the main reason why ISO is called ISO, even though it’s a measurement of light sensitivity of a camera sensor.  So ISO 100 on my camera will be ISO 100 on your camera, regardless of brand.

Now, there will be some slight variations on the exactness due to wear and tear and the specific environment being shot, but for our purposes, as photographers, it’s essentially the same. And ISO, as far as photography is concerned, simply refers to a cameras light sensitivity. And, as you the photographer, change the ISO setting, your actually adjusting and setting the sensitivity of the sensor of your camera to ambient light.

As camera technology has progressed over the years, the light sensitivity of the sensors has also increased significantly.  So much so, that we have the ability to shoot in very dim rooms and still be able to see recognizable subjects with relativity minimal noise. With that, our ability to remain versatile and shoot on the go in ever-changing lighting environments has only gotten better.

Nonetheless, it’s important that you understand ISO and how it affects your photography. And really understanding ISO is a fundamental and key part in even being able to get properly exposed sharp images.

What are some common ISO’s?

Common ISO’s are very much camera dependant these days. But, in general, ISO 100, 200, 400, 800 are the most common. Some cameras have the ability to even go as low as ISO 50. The increments ISO go in will be dependant on your camera’s native ISO. Native ISO is the lowest number available in our camera and is also the setting that will give the best image quality possible. Definitely, something to keep in mind.

So, what exactly happens when you change ISO?

Let’s say you go from ISO 100 to ISO 200. What you’re actually telling the camera to do is double its light sensitivity. Both cameras and light in general function exponentially. Meaning, the values go in fractions that either double (when you move up a step) or halve (when you move down a step):  100, 200, 400, 800, 1600, 3200, 6400, etc. So changing from an ISO of 100 to 400 is actually making the camera 4 times as sensitive to the ambient light in the room (since you’ve moved two steps forward).

And moving from ISO 800 to 200 is making your camera ¼ as sensitive. We don’t really need to know any specific or special math here. But, this is important when it comes to getting proper exposure when you’re trying to figure out why an image is too dark or too bright.

Take a look at your camera now, navigate to the ISO settings. Notice that the values only move in doubles?

Wait… Mine have more numbers… Lucky you my friend, that means your camera has an ISO range that moves in ⅓ steps to give you more flexibility. But, even so, this still applies to you as well. When you move from ISO 200 to 400,  regardless of the steps between, you will move the overall exposure of the image up by 1 stop.

And that right there, that’s what is happening when you change the ISO setting in the camera. You’re either telling your camera to be more or less sensitive to the available light by the amount you set. By doing these changes, we will directly affect the exposure of our images. We can either increase or decrease exposure by increasing or decrease our cameras ISO. Increasing it will make the exposure brighter while decreasing it will make the exposure darker.

Now, ISO will affect other elements of the photo as well besides overall exposure but know, it will not directly affect either your Shutter Speed or Aperture settings in any way. Shutter Speed can be used in conjunction with ISO to adjust exposure, same applies with Aperture. But both settings have very different affects on a photo than just exposure alone. Even still adjust ISO has no affect on either.

Is a higher or lower ISO better?

Well first thing, what exactly is a “high ISO?” Most photographers would say that’s between ISO 1600 to ISO 3200, depending on what subject matter they shoot. For me personally, I’d say ISO 1600.

As far as which is better, lower ISO is better no questions asked. ISO 100 (or ISO 50 if your camera has that available) is as good as your camera can possibly be and we deliver the sharpest images. However, with most digital cameras now, ISO doesn’t really matter quite as much, especially from ISO 100 to ISO 800.  Images across all camera’s and brands will still noise free and sharp.

The issue with higher ISO values is only really apparent when an image is magnified or printed at higher resolutions. On smaller formats (i.e., instagram or smaller online posts) you’ll probably never see the noise in an image or reduced sharpness, even when shooting at ISO 1600. However, if you print an 18 x 24” print or larger, then yes you may see noise, especially in the shadows of the image.

As ISO increases, the sensitivity increases yes. Which does mean you can shoot in low light environments. But so does the amount of noise that your sensor picks up as it eventually begins to struggle to pick up any available light. And that right there is really the drawback. You get noisy photos that aren’t clean and as sharp. Now, increasing the ISO only slightly doesn’t always mean more noise. However, after a certain point, absolutely yes. There will definitely be more noise and a noticeable reduction in sharpness.

In general, 3 stops lower than your cameras maximum ISO setting would be the highest you’d want to set your ISO to if you want to have a usable and recoverable image even with noise that is still decently sharp as well.  Now, if you plan on using noise reduction software such as Adobe Lightroom or Adobe Photoshop to reduce noise, then you can shoot upwards of ISO 25,600 and still have usable images.

With that, the lowest ISO you can set your camera to given the situation will always be the best one to use. That’s the best rule of thumb, always set your ISO to the lowest you possibly can. And only go up, if you absolutely need to in order to even take the photo. If your camera goes to ISO 100, then ISO 100 is best. If it goes to ISO 50 or ISO 200 instead, then those are the best settings for optimum image quality.

If you have the ability to shoot in a brighter environment either by increasing the available light, slightly adjust the angle you’re shooting or moving completely, those will always be the best. But, if that’s not possible, set the ISO to the lowest value possible to get the shoot properly exposed.

Before moving on, take the time to do this experiment to figure out what’s the highest ISO your camera can go to without there being too much noise in the image:

During sunset, one evening, go outside and shoot a flower or tree branch. Set the Aperture and Shutter Speed so that you can at least see the image at ISO 100. Then, leave the Aperture and Shutter Speed alone, and shoot one image after another changing  ISO only. Shoot these ISO values: 200, 400, 800, 1600, and 3200.

Once finished, transfer each of these images to the computer and look at each image specifically for noise. Whichever image you feel is still easy to view and sharp to your liking (even with a little noise) is the highest you should set your ISO to, period. For me personally, I wouldn’t go above ISO 1200 personally.

Note: you can underexpose the shot by 1 to 1 ½ stops then adjust the exposure in post-processing.

When should you increase or use a higher ISO?

The main times you want to increase ISO is the following:

When shooting handheld without a tripod and can’t use a Shutter Speed below 1/80 second.

When shooting action, either indoors or outdoors, and you can’t go below a shutter speed that’s fast enough to freeze the action you’re shooting. For example, a shutter of 1/2000.

Shooting at night or shooting star trails, where you’re shutter is as slow as possible and you’re images are still too dark.

You want to increase Depth of Field, but you can’t change your Shutter Speed.

What are the best ISO values for indoors?

For shooting indoors, stay below ISO 1600 if possible. On most cameras, ISO 1600 will be the maximum that you want to shoot at, only because from there onwards the noise will be incredibly visible. Ideally, for indoor shooting, stay between ISO 400 to 800. If you have a tripod, this would be a very good time to use one.

Shooting on a tripod will allow you to shoot at a lower ISO and, instead, use slower shutter speeds to compensate for the lack of ambient light. In general, that’s the best way to handle shooting indoors in low light so you can avoid having to shoot at higher ISO. Now, whether or not slowing down the shutter is a good idea will depend on what you’re shooting indoors. If you’re shooting fast-moving subjects and need to freeze action, you’re best of leaving the Shutter Speed alone and increasing ISO.

What are the best ISO values for outdoors?

For outdoors during the day, the best will be ISO 100-200. Since there should be plenty of ambient light, there’s no reason to set the ISO higher than 200.

When shooting outdoors at night, the best ISO will be the maximum you feel that the noise isn’t too distracting. See the experiment mentioned above for how to determine that. Best practice is set the ISO to that maximum value, then adjust Aperture and Shutter Speed so that the image is properly exposed.

When shooting at nighttime, since ambient light usually isn’t the greatest, it’s best to shoot on a tripod so that you can shoot at slower speeds to help pick up what ambient light is available and avoid having to increase ISO. But, if you’re shooting handheld, just know you’ll have some noise in your images and very shallow Depth of FIeld when shooting subjects at night.

What to look for in ISO when purchasing a camera?

Well, since ISO is light sensitivity if you find yourself shooting a lot in low light conditions whether they be indoors or nighttime, consider comparing ISO ranges between cameras. Some cameras have larger ranges than others. The drawback of a larger ISO range often means that the sensors are not as sharp as lower range ISO cameras.

But, the advantage is that larger ISO range cameras often have the ability to shoot relatively noise free and sharp images at much higher ISO values than their counterparts. For example, a typical DSLR or mirrorless camera may become noisy at ISO 1600. While the large range sensitive camera may become noisy at ISO 3200 or 6400. In low light conditions, these cameras perform significantly better.

what’s going on guys so today we’re gonna talk about ISO in photography and how it relates to your photography so we can actually take control of it and get the photos that you really want so let’s kind of start talking about ISO as far as like as a technical term what does it actually mean it stands for international standard organization international standard organization was actually be the manufacturer the actual like organization or laboratory to figure out and standardize what light centers the sensitivity is in photography so I so really just stands for international standard for the organization which they’re the people that actually standardize light sensitivity so as far as when it comes to ice own photography it just means light sensitive its sensitivity how sensitive our camera sensors are and or our lenses as far as picking up light house n sitive our cameras are in terms of the light that they can see in an ambient environment and that’s definitely something that has to be looked at when you’re comparing cameras and that’s something that we touch on but that right there is really the main reason ISO is called ISO and it’s just pronounce ISO so the idea with having light sensitivity or ISO being standardized between every single camera brand and every single camera manufacturer over the last 60 years is so when someone sets for example in a camera they said ISO 100 the idea was with ISIL as an organization to standardize that was so that ISO 100 across every single camera is exactly the same I’ll be obviously there’s gonna be a little bit of variation depending on on really how the sensors built and the manufacturing like as far as ingredients in the equipment that was used to manufacture the sensor and every brand and manufactures a little bit different as far as the technical the technical background and the the process in which they create something like that so there’s a little bit of very variation in that but the idea is that ISO 100 be universal across every single camera making model up until today so that’s really what ISO stands for so what happens when you actually adjust ISO on your camera what are you doing as a photographer when you actually change ISO say from I saw 102 I saw 200 what you’re doing in theories you’re changing the light sensitivity you’re telling your camera hate the ambient light in this environment is not bright enough we’re gonna have to increase your sensitivity so you can actually see the light in this environment and get the proper exposure that I want that’s really what you’re doing when you’re changing ISO and that’s the function it’s just a measure of light sensitivity so as camera technology has kind of progressed over the last couple years our ability when it comes to not only readings lights at sensitivity in lower light environments but also the ability for our sensors and our cameras to to have an increased amount as in terms of range that they can actually still be relatively noise free all of that stuff has increased over the last 10 15 years especially with the mirrorless kind of taking over and dominating and all that now camera manufacturers going onto that and reducing weight and being able to hire higher construction equipment as far as making sensors and because the cost has been reduced so ISO now is not nearly as something that you kind of to look out for as much as it used to be when you’re shooting film if you didn’t if you didn’t get the proper exposure or the film back in the day you wouldn’t have a properly exposed image and the image would not be usable there’d be too much noise it’d be too much grain if you’re not shooting at a low enough Aysel but with now with digital cameras we don’t really have to worry about ISO as much but you still need to know exactly what it’s doing so you can get the shots that you really want so let’s talk about what are some of the common ISOs some of the common ISOs that that you’ll know and you’ll see and then you’ll become familiar with our ISO 100 hundred four hundred eight hundred and maybe sixteen hundred some cameras have the ability to shoot below ISO 100 so maybe ISO fifty as well and I I do want to kind of clarify before you go before we go on the ISO values that your camera are gonna have are gonna be determined based on the native ISO that your camera has so for my my camera shoot the Sony a7 the native ISO is ISO 100 that’s the lowest possible setting on my camera can go to when I’m adjusting the ISO values for your camera it could be so fifty and that that right there would be considered a native ISO for most cameras it’s usually 100 or 200 but some cameras at least now they do have ISO 50 which is just going to be even that much more in the screen there are technical reviews that have been done to determine whether ISO 100 versus ISO 50 are really making that big of a difference sometimes people are just saying it’s just a manufacturing kind of thing long story short there you have to do the research to really see if I saw 100 ISO 50 is going to be really a big enough difference for for you based on the way that you shoot to really care about for me personally I don’t have that ability to shoot at ISO 50 but if I did it wouldn’t really matter that much but I just shoot at ISO 100 so what happens when you’re actually changing I so like I mentioned before in kind of introduction when you’re changing ISO on your camera say you’re going from 100 to 200 you’re you’re adjusting the light sensitivity of your sensor you’re telling the sensor okay hey the ambient light in this in this environment it’s actually too low and we’re going to need to make you more sensitive so you can actually pick up the ambient light and and that’s what you’re doing when you’re changing ISO and you’re increasing those values you’re actually making the camera more and more and more and more sensitive by an exponential factor actually because the thing you have to kind of know with photography it works in exponents it doesn’t work in just normal sequential numbers in the way that we would like it to work it’s more mathematical so it does actually work in exponents so say you go from ISO 100 to 200 you’re actually doubling your ISO and then if you go from ISO 200 to 400 again that’s a factor of 2 you’re doubling your ISO and then 400 to 800 that’s also at doubling those right there those values that talked about are actually stops the light as well so if you go from say ISO 100 to ISO 800 you’re actually increasing the overall sensitivity by a factor of 8 so you go from 100 200 that’s to 200 400 that’s another 2 so that’s that’s you know that’s another 2 and then so that would get you to 4 and then if you go from 4 to ISO 400 ISO to ISO 800 that’s another 2 on top of that so two times two times two right that gets you to a factor of eight it doesn’t actually work in the way that it you would think it would and just like hey if I go to ISO one or two hundred it’s just like one but now it doesn’t go that way it works and functions a multiple of two the same thing applies if you’re actually going from an ISO of 800 all the way down to ISO 100 you’re actually reducing the sensitivity of your sensor by a factor of an eighth at that point so you’re going to go like times 2 or 1/2 from 800 to 400 and then another half from 400 to 200 and then another half from 4 200 to 100 so that’s actually a factor of 8 so that’s kind of just like a technical we don’t really need no math and stuff like that but just so that you know that’s how ISO is actually being changed most cameras also have if you’re looking to your ISO settings they’re gonna see 3rd stops and the purpose of having a third stop when it comes to changing ISO is that you can actually change the exposure in the light sensitivity more specifically because what used to happen when there wasn’t actually 3rd stops as far as changes in ISO values you wouldn’t actually really get it precise exposure you’d always have to underexpose or overexpose your image by somewhat some fraction of a stop so a lot of camera factures camera manufacturers now I’ve actually also added that the third stop just to make it a little bit easier for us to to get the proper exposure that we want so you’ll also see that you’ll see ISO 100 you maybe see 120 you’ll see 160 180 and then you’ll see 200 those are all just third stops the third stops are going to be increments of 1/3 between the lowest one not necessary just lowest built any the lower ISO setting that you’re on and then the next higher ISO setting so if that’s 400 and 800 then you’d be like 640 720 whatever the other number is those are the factors of 1/3 stops and that’s what they’re doing they’re just giving you more fine-tune controls so what else do we need to talk about so let’s state so if you take a look at ISO right so let’s say for example you’re looking at ISO how do we define a low versus a high ISO in photography is that’s something that’s going to be like a higher numbers like a better value or is the lower a better value simply said the lowest value that you can set your camera to in terms of ISIL is going to be the best for me since it’s 100 100 is going to be the best for my my camera am I set up for you it could be iso 200 it could be I so 400 it could be 50 those would be those would be the best settings whatever is the lowest setting that you set your ISO to is gonna be the best setting for your camera that’s gonna give you optimal image quality that’s going to give you the sharpest images with the least amount of noise and it’s also gonna make your make your camera put your camera in a position where you can actually adjust the aperture and the shutter speed to get the results that you really want as long as you have enough light so when when you’re actually making a change to ISO so let’s say you you wanna you’re you’re in a situation where it’s kind of a little bit lower light and you’re just like man I need a little bit more light if you move the eye soul like then you increase the value you’re actually gonna also increase exposure of the of the shot if you take that that shot and they look at it on the back you can begin to increase the exposure but the same time it does more than just increasing exposure and the same thing happens when you when you make changes to aperture and shutter speed as well and we’ll have video as explaining that stuff as well but when you change any setting photography there’s more there’s more impacts to sleep there’s more impacts to than just changing just the setting itself as far as how it changes exposure so when you increase or decrease ISO you’re actually going to also increase the sensitivity of your of your camera sensor with that the more sensitive that it becomes typically it amplifies the amount of noise that’s going to be in a photo that that that amplification comes at usually above ISO 1000 but every single camera is different when it comes to its sensitivity and when it she hits a north-north sholde the biggest advice I can give someone if they were trying to figure that out and they just got a new camera go outside on sunset and and just you know just regardless if you’re shooting on a tripod or not just just shoot a stationary object and like kind of lower light conditions so that’s why I say sunset set your your your ISO 200 set your shutter speeds so you can at least get some what kind of a properly suppose photo and shut your set your your aperture so that you can get just proper exposure and then just adjust your your iso only and leave shutter speed and aperture and then increase it little by little until let’s say go from iso 100 200 400 800 and then 1200 and maybe even 3200 and then bring all those photos up in in post and just whether it be in Camera Raw or just bring them up on a computer and then look at them and look specifically for noise which ever ISIL has the least amount of noise that you that you think is okay and acceptable it would be the highest you should ever set your ISO to that’s the biggest way to figure out like what the maximum ISO should be for your camera for me personally that’s usually about 1200 now if I’m shooting over 1200 then I know I need to do some noise reduction and we’ll have a future video and maybe a blog post explaining how how to actually reduce noise by using post processing software but that’s what I would do personally for your camera it may be different to be higher every camera is different when it comes to their noise threshold so for my mic for my actual cameras it just happens to be 1200 to 1600 is usually where I feel like it’s just too much noise and it doesn’t make any more sense but the thing is when it comes to noise in an image if you’re just using photos and you’re just posting photos online it doesn’t really matter if you have have a lot of noise because for the most part the images like this big it’s being viewed on than just the phone and for the most part that noise is only gonna give you kind of greater detail depending on what your subject matter that you’re shooting is and the only time noise is really issues when he starts to blow up and imaging you start to magnification say you have a print that’s 18 by 24 or 24 by 48 at that point you’ll definitely see the noise billboards if you’re standing in front of the billboard looking at the billboard you’ll absolutely see the noise in magazine prints definitely will see the noise but on just social media and just Facebook or Instagram or whatever Pinterest but the most part you can get away with shooting at higher ISO because no one’s really gonna know it’s Dallas or another photographer that’s looking specifically at details in your photo but typically when it comes to shooting and if you want the best images just set your ISO to the lowest possible value for the situation that you’re shooting in so if you’re shooting outside and you’re just like man I you know I need this certain amount of depth of field I can’t change my aperture and you know I’ve slowed down my sugar as much as I can and I don’t have a tripod so I can’t go below 1/100 of a second like at that point you’re just going to set your aperture to whatever value that you can actually get a properly exposed photo unless you’re gonna do post-processing then at that point you can usually go a stop stop and a half over underexposed and you can still recover that with some marginal detail but at the same point it just depends on the situation that you’re shooting you’re gonna be kind of in situations where you’re gonna have to you know push and pry on the camera settings to like hey I just need to get a photo and sometimes with getting a photo you’ll have to kind of compromise a little bit on getting more noise and that’s kind of one of those situations so otherwise if you’re a situation where you’re shooting your say you’re shooting sports and you can’t adjust your charge speed past a certain point because then you’ll get blurry subjects at that point you’re gonna have to kind of increase the ISO to get the proper exposure especially if you can’t increase your aperture either or decrease your aperture to kind of get more light coming in another situation would be just like hey I need to have a certain aperture you know I’ve reduced my shutter to the the lowest I can get but like do they have to use this aperture like you know I have to shoot at f11 or f-22 because I’m shooting outside at that point that’s why you’re gonna have to increase your ISO those are kind of the situations where you’d have to shoot like increase your ISO but for the most part you don’t really need to if you’re in situation where you can increase the available light either by moving or adding some artificial light or changing the way that you’re shooting or maybe just rescheduling and shooting it in a different location and environment that’s possible that would always be better than changing the ISO because once you get over a certain point you’re just gonna get noise unless that noise is something you’re okay with but if it’s not then that’s gonna be one of the compromises you’ll have to make outside of that when it comes to I guess other considerations with with ISO is that it doesn’t doesn’t ISO directly it’s not gonna change change or impact your sharpness it’s only gonna cause just noise after a certain point that will reduce sharpness just because the noise will be too apparent but for the most part it doesn’t directly influence your sharpness so I guess biggest other takeaways that can I can kind of leave us as parting advice for someone that is kind of just jumping into ISO and they’re not really they’re not really sure what are some of the best practices hey if you’re if you’re not shooting on a tripod definitely consider shooting on a tripod if not you’re probably gonna have to increase your ISO if you’re shooting indoors and low light or you’re shooting outdoors a low-light and again you’re gonna have to you’re gonna fight that that battle just like hey I have to increase it just to get a proper shot when you’re shooting action best to shoot on a tripod – if not you’re gonna also increase your ISO if you’re shooting night and you’re shooting star trails and you need to create depth of field and it’s still gonna be dark you’re probably gonna need to either tripod or gonna increase your ISO if you want a really great depth of field and you can’t go change your shutter speed definitely gonna agree sir ISO definitely should not tripod if possible and as some partying kind of pieces and tips and tricks and pieces of advice what are some of the best like ISO values to shoot if you’re shooting indoors for the most part shoot just below whatever your camera’s maximum ISO is I ideally state between 400 and 800 ISO just so that you have enough light that you’re you’re making a camera more sensitive at the same time you can you don’t have necessarily noisy images most cameras up until 1000 to 1200 they’re still gonna be pretty noise for you it’s not until you get after 1600 for the most part they’re gonna be noisy so you have a little bit of room there that kind of wiggle with as far as if you’re if you want some of the best ISIL for shooting outdoors for the most part if it’s bright sunny day hundred 200 maybe if you need a little bit more like coming in outside of that if it’s low light at night I mean you’re gonna have to shoot between four to eight hundred maybe 1200 you’re gonna get to that max if if you can’t necessarily shoot on a tripod or have a more shallow depth of field and the last final thing let’s talk about what you should look for when it comes to ISIL when you’re purchasing your camera every single camera is different when it comes to ISO and noise sensitivity and light sensitivity so the biggest thing is that if you’re gonna be shooting a lot of low-light conditions look for a camera that has a really large weight range when it comes to ISO some cameras have ISO ranges that start from iso 125 thousand to two hundred thousand to five hundred thousand and that range is going to also determine when at which point they actually begin to get noisy for my camera since it only goes to 25 600 I believe is the highest it gets a noisy pretty low e only gets it gets noisy at a thousand 1200 1620 gets noisy but if a camera goes to all the way to an ISO 500,000 it’s not going to get noisy until ten thousand which means you can shoot in a really dark environment or low-light environment and you can still get pretty sharp images way better as far as north performance and I will get on my and if that’s important to you man absolutely check out a camera that has a greater range when it comes to ISO sensitivity that’s something you could check out when you’re looking at cameras on B and H or dxo mark if you want more specific specific test point stuff like that or you know you’re just on Sony or Canon or Nikon website and you’re looking at cameras that’d be the best place to find that in the specifications breakdown but it depends where you guys are shooting long story short I mean just try to keep the ISO as low as possible but just know for the most part it doesn’t matter until you get to a certain point and they’ll negatively affect your photos just in terms of noise and reduce kind of clarity because the noise is gonna take over it’s not gonna mess with means that the image will be not as sharp but it’ll be distracting after a certain point so that may be perceived as a lack of sharpness but doesn’t really affect that but if that’s important to you guys then by all means definitely look into a camera that has that that larger range so you can you can get the most out of your ISO ranges alright guys that wraps up today videos that were absolute today’s videos guys so you know I got a microphone just out of randomness just to drop the mic on you guys as far as subscribing buttons below you guys already know what to do the like button also down there you might as well just kind of slide that mic that mouse over just tap that to you real quick more information can be found on our website up here and if you want more detailed blog posts as you know if you don’t like the way of talking doesn’t like that whatever that may be you can read it here more of a reader you can find that right up here until next time guys
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Devaun Lennox

I'm a fashion, beauty, and commercial photographer turned impromptu photojournalist. Based in Las Vegas, my images are graphic, bold, and full-on contrast.