A Simple Explanation of ISO for Digital Photography and Video

In this video I give a basic explanation of ISO in digital photography and video. I explain why a higher ISO results in more noise.

[@EdgarHernandez-xj5mx]

Why are there no comments here? This video is amazing! I had no idea! Well I had some idea but all I knew is that it was pumping more electricity into the sensor. Now I know more or less exactly what’s going on!

[@DylanBennett]

This video (and others) had thousands of comments. But then last year, KZbin went nuclear on a huge number of creators and "helpfully" (🙄) wiped out every comment on every single video on a ton of channels. Then they locked and disable comments channel-wide for an entire year, until just a few weeks ago. Go figure. Anyway, thanks for the kind words. I'm glad the video helped. 😊

[@postnavodi]

I don't comment usually, but it took me a while, like 10-15 videos to click on in order to find something like this. I am a very beginner, but knowing myself, I can't just go over "Bigger ISO for darker photos, but don't overuse it" without asking why and what is that, because shutter speed and aperture are pretty easy to understand. Thank you, it's a fantastic video and very well explained.

[@robertbutwell]

Great explanation. Don't forget, noise is also result of heat generated by the sensor itself. Each pixel reports heat (IR) behind the RGB filters as light. This becomes significant in deep-sky astrophotography.

[@ashbankswav]

Love your videos. Your soothing voice, the little sketches to visualize what you're explaining, and the simplicity of how you teach. Very easy and encouraging. For someone such as myself that has watched HUNDREDS of videos and still left a bit confused, would be dope if you updated us with some 2020 tutorials. Until then all the best!

[@SlaySagar]

These 3 videos are the best I've ever watched to understand the key concepts in photography! Absolutely amazing! Thank you Dylan!

[@ldr8276]

Just watched the three videos in your learning series- SO helpful. This is why I love youtube. Thanks Dylan!

[@samihuseinmorgado8513]

I have to say that this is possibly the best and easy to understand explanation of ISO and noise in sensors for digital cameras. Thanks a lot

[@pumiehoan]

Your videos are amazing! I haven't looking everywhere for someone can explain to me what happen inside a camera & you appeared & become the only one I can understand 🥹🥹 I hope you'll release another video about shutter speed🎉. Thank you for making great content!!

[@davidbickford365]

I am more knowledgeable about camera basics because of your 3 videos. Very Well Done!! Thank you.

[@MichaelCurzi]

Incredible videos in the photography series, thank you! I will watch every one you produce

[@bullfighter6951]

Fantastic explanations. Please keep it up and provide more!

[@nandhukr331]

Amazing class sir. Thank you so much 👏 from kerala India 🇮🇳 ♥️ . Expecting more classes from you

[@tomhalina4284]

Thank you for answering my question 11 years before I asked it.

[@byronjohnson8346]

EXELLENCE EXPLANATION, THE DETAILS REQUIRED FOR ME TO LEARN WITH A HIGHER LEVEL OF UNDERSTANDING. ✌️

[@sakshigghodekar576]

Your explanation is too good and concept clearance is best

[@phalansheeshev]

Not all heroes wear caps ❤, loved your explanation

[@MayankkumarMishra]

You should make more explanatory videos like this! It was a gem! Also the other videos about aperture size and depth of field were phenomenal!🔥🔥

[@jpsteiner2]

Best explanation of ISO ever!!

[@sanket6860]

Now I understand how it actually works! Great explanation 👍🏻

[@tobiaskaspar]

Outstanding Dylan. Great job!!! Thanks for this video.

[@thomascantrell8530]

Great work! More vids for beginners, like how to get my macros in focus! Thanks

[@jeroenbeukers2711]

Phenomenal Dylan! Thank you for the education, best I've ever seen on this subject! 5 star!!! :0

[@KarinaModelChannel]

I'll wait another 11 years for more videos

[@goldog2816]

Great video , I understand how to use ISO when shooting but I never knew the reason or what was really happening,, I just remember when I learned on film back in the early 70's I preferred low speed film because it was less grainy and color saturation was better problem was you had to have a really steady hand to get really sharp photos,, digital has really been an amazing advancement now we can do things so much easier and better........

[@axolotl5327]

Great explanation

[@MotiveCap]

Wicked video, I'm learning so much from these.

[@HarishPillay]

Thanks for this video. Very well stated and explained.

[@parshurammagaji]

Great explanation on ISO! thank you so much.

[@wantxapas]

That was such and amazing explanation. Thank you very much.

[@anirban1949]

Hey man, why not you make more mind-blowing tutorials on photography and videography like these...plz.... we all will wait for your uploads. Lots of love from India💜💜💜 and also You are a genius. Thank u 🎉 .Hope u doing well these days😊

[@hectorhdz8426]

I saw your three videos explaining DoF, F/stop, and ISO. You mentioned in one of these videos you were going to do another video explaining the shutter speed, did you do it? If so, please share the link. Thanks

[@tusharkaore]

Awesome videos... Please add more to the photography playlist 🙌

[@takefivevideos]

Certainly does help Dylan. Thanks.

[@Twobarpsi]

Excellent!!

[@rre9518]

Good job!!!!

[@Sams911]

so why is higher ISO film more grainy? Can't be magnetic fields there, right?

[@mattparkin7224]

The halide crystals are larger

[@mycarolinaskies]

Film is made of an emulsion that dries to crystaline structure of uniform crystal size. The larger the crystal the more sensitive to light, but fewer crystals form in the same confined area.

[@jvw3443]

This is a great way of making something daunting perfectly understandable, thanks!! Tiny little side note... It's not I-S-O, but just ISO. It's not an acronym :)

[@krystianstepien1043]

Well, it is an acronym. It stands for International Organization for Standardization, which made norms for film sensitivity named after organization

[@axolotl5327]

@@krystianstepien1043 It actually comes from isos, the Greek word that means equal.

[@krystianstepien1043]

@@axolotl5327 That is true, but not in this context. Check it!

[@axolotl5327]

@@krystianstepien1043 I checked but didn't find anything wrong. Can you elaborate?

[@krystianstepien1043]

@@axolotl5327 Sure. Iso-, as an prefix means equal, but it has to be attached to the other word, such as isotope. Standalone, it has no meaning. Acronym ISO, on the other hand, stands for International Organization for Standardization and is used for all the standardized measures, such as film sensitivity.

[@philo-phineasfrederikzen2999]

Dankon pro alŝutis de fotaj filmetoj! Ili estas tre interesaj!

[@ignaciomorales1681]

New subscriber. Thanks!

[@waynem4226]

this is great

[@oatdawg234]

Hey Dylan thank you for all your great work. The question I have is what software are you using for you chalkboard video? thanks

[@tedk2814]

great!! thanks

[@fedesartorio]

Really good video! So iso basically works like gain in audio, but I’m amazed by the performance of modern cameras. Are there any specific camera companies really researching ways to make sensors with extremely low noise floors, and ways to amplify the signal efficiently? Or is that a general goal of all sensor makers?

[@LisaNordlicht]

Wow, thank you so much, dude!

[@alphonseraj9434]

Hi... I think gain and iso are slightly different in the sense gain is base iso for a camera.. could be 800 iso or 1200 iso ..unlike ISO which is an increase without taking into consideration the base iso..of that sensor for a perticular camera like Sony A7 s or fs7 they have base iso which is fixed gain... And works best at that iso ..

[@abdulfattahazooz]

what about the base iso

[@CyrilleBoucanogh]

There's difference between digital ISO in photo cameras and GAIN in video cameras. ISO highlights/boosts the shadow area. Gain simply boosts the brightness. Gain doesn't effect the color curves. ISO always does, making colors brighter.

[@BrokTheLoneWolf]

This seems like the visual equivalent of compression in the audio world

[@samuelshasa]

it basically is

[@sakshigghodekar576]

Thanks you a lot

[@ishukalia1099]

Thanks

[@krapotkin71]

NO it does not refer to the sensitivity of the sensor.. sensors are NOT able to vary the sensitivity. ISO is GAIN added AFTER exposure.. just like turning up the volume on a radio... likewise ISO doesn't generate noise it amplifies the noice that is present from the start... light is analogue.. so is the sensor in your "digital" camera.. the signal turns digital after the AD converter and then goes to the image processor.. the ISO (also not an acronym but short for ISOS and means equal) is added between the analogue and digital steps..

[@Andratos95]

I would like to point out something though. There's a great misunderstanding that people think about when talking about ISO. You seem to be implying a high ISO introduces noise. That's false. An high ISO amplifies both signal and noise, so the SNR (signal to noise ratio) is the same. You gave an example of a situation where a sensor doesn't receive much light (the second graph you drew), and by raising the ISO it looks like that's what's increasing the noise. Well, that's not true! The noise is already there to begin with, increasing the ISO is not actually changing that. Noise is strictly dependant on how much light actually hits the sensor. In ISO-variant cameras actually, given an underexposed shot, a higher ISO will actually produce a less noisy image than a lower ISO with increased exposure in post processing!!! In ISO-invariant cameras, the noise will not differ with ISO, but it will still be convenient to keep the ISO low to avoid clipping highlights due to overexposure. That's the main reason to keep ISO low, to avoid overexposure and decrease in dynamic range. It's not about noise (but yes, it's a great misunderstanding of ISO). To understand this better, here's a link of someone who explains this better than I do: photo.stackexchange.com/a/35141/77187

[@mycarolinaskies]

Noise comes from mulitple sources, internal and external. External is shot noise. In this video he is dealing with noise created IN CAMERA. There are two agregious sources in camera, READ noise and HEAT. READ noise is caused in the conversion from analog to digital and signal boost(ISO/GAIN) in the ADC conversion. This is what is better dealt with in modern CMOS allowing them to achieve higher ISOs and with some invariance. HEAT noise is derived from on-board devices heating up over time including overall sensor, power cores and batteries. And unless cooling is implemented this noise persists and can effect images over a series.

[@scsamjamx2498]

Untrue noise always exists in light sensors. In low light you have low signal leading to a relative bad signal to noise ratio (snr). Same sensor more light gives a higher signal with the same noise gives a better snr. Adjust the gain on the low light low signal case can increase the signal so it is the same as the more light case but you still have the bad snr because the noise level also was increased. The noise will appear in the image. This increase in signal due to iso only will lead to more noise.

[@davemannn]

If this were explained in simpler way...apes might be able to understand...and we all know how that turns out... Thanks!

[@richardbutler8532]

Unfortunately, this only really explains read noise. In a lot of instances, your bigger problem is photon shot noise (the fact that the light you captured is itself noisy). Focusing solely on read noise risks embedding the idea that it's the camera's electronics that make high ISO images noisy, which is only partly true.

[@mycarolinaskies]

Signal source noise can be scaled down by increasing exposure time. In astrophotography we get better signal to noise ratio by exposing for longer periods of time in dark skies or in light polluted skies by iterative short exposures stacked to weed out source noise(we would call skyglow). Iterative stacking images can then be processed based on normalized adjustments and subtractions of flats and darks. A dark being a lens covered to show interior noise and a flat to take a white background to eliminate optical and broad source variations in light.

[@richardbutler8532]

@@mycarolinaskies I agree. Astro is an interesting edge-case but even there you're acknowledging the need to increase exposure to boost SNR. This video is very pretty but doesn't ever point out that capturing less light increases noisiness/decreases SNR (and would do even if your camera added no noise of its own). Since this vidoe isn't solely about astrophotography, its omission of the impact of photon shot noise ends up being misleading.

[@jeffmangione2024]

sorry mr bennett but 85% red plus 50% green plus 75% blue equals 210%. there's a mix up between measurements. if you see 100% as pure white you have to have 33,3333 % of each color.

[@mattparkin7224]

The percentages are percentages of each channel's full potential exposure, not the percentage of the final image

[@mycarolinaskies]

He didn't go into this, but a Bayer mask interprets 4 pixels into a single color pixel interpreted off-sensor. Typically this mask is RGGB. CMOS are highly sensitive to Red and Near IR light so that channel is typically higher. Read off of the signal of each of those 4 pixels is combined to develop the color produced and overall signal.