So generally, I’ve always understood that the lowest ISO is best to shoot at. Though with newer cameras, they usually have a higher base ISO and in some cases Dual ISO.
I usually work with the R5C, even for photography. It feels odd to take portraits at 800 ISO because I’ve always been told it should be as low as possible.
So does the Base ISO system, negate the need to shoot at lowest ISO for the clearest and least grainy image?
This is a myth that hammers way too many new shooters.
The correct ISO is the best to shoot at, regardless of what that ISO might be.
Dual ISO is not so much about noise as it is about dynamic range. It’s important, but it’s about maximizing details in your shadows when taking poorly/dimly lit photos.
Base ISO is an arbitrary number. If it’s 200 or 100 it means the same thing: “I have all the light I need, boss!”
It should be as low as possible, but not for the reasons you’re thinking.
In and of itself ISO has no adverse effect on your shot. (Heads are exploding everywhere right now)
ISO does not cause noise. The noise is because you did not have enough light and had to raise the ISO… but the noise was already there because you were not capturing enough light. Raising the ISO just lets you see that noise.
Assuming ISO 100 is the correct ISO for a shot the reason it is better is because your sensor is being completely saturated with light - more than enough light to hide the noise that’s there - and you therefor do not need more ISO.
ISO is the alarm bell that tells you that you are not saturating your sensor with enough light, and so you will have visible noise in your shot. ISO 800 is telling you that you’re missing 3 stops worth of light.
tl;dr – If you do not have enough light you will have noise. It is just that simple. If you have to raise the ISO, do it, because you’re not hurting anything by doing so. A better option when doing portraiture however is to gather enough light that you do not need to do that in the first place. A longer shutter speed, a wider aperture, or add light via flash/reflector (or some combination of these) is what is needed… but if all else fails, raise that ISO without fear - and deal with the noise you’re going to have in post.
My keeper rate is noticeably up after switching from manual ISO to auto ISO and focusing more on shutter speed.
By my count, ISO 800 is a sign that you’re missing 9 stops of light.
https://filmphotographystore.com/products/35mm-color-kodak-super-low-speed-1-roll
This.
Even camera manuals have this fact wrong. Not to mention photo sites and conventional wisdom on the Internet.
Noise comes from light. At least the biggest part of it does. It does not come from the sensor, or amplifying sensor noise, for the most part. As equipment gets better and better, equipment noise has gone way down. Almost all of the noise you see is from light itself and there is nothing than can be done about it.
Seeing more noise at higher ISOs is because light noise is related to the square root of the number of photons. A lower number has a relatively higher square root. Less light has relatively higher noise. In lower light conditions, no matter what you do, you are working with less light, and thus more noise.
The base ISO is the one where the sensor system is designed to have the highest signal to noise ratio at the “correct” exposure.
Pretty much right, though I’ll clarify a bit if I may:
Noise is related to the number of photons. What the square root gives is the standard deviation (due to the Poisson distribution that light particles follow) and “noise” is the signal to noise ratio, SNR, the ratio of the number of photons to the standard deviation. And this is of course funnily also the square root of the number of photons.
I do understand what you mean, but this is IMHO rather confusingly put and especially for beginners impossible to comprehend what you mean.
Simply, more light means larger SNR. The standard deviation of the signal goes up, but the signal itself goes up much more. What an observer sees as “noise” is simply a product of low SNR.
The image sensor has no ISO at all. It can be run at different parameters and typically changing the camera’s ISO setting changes there operational parameters.
The concept of “base ISO” isn’t officially defined (by ISO, the organization) and can interpreted in many ways. If we go by your definition above, then it would be typically the lowest extended ISO setting as the exposures are typically larger than the ones with the lowest “regular ISO” settings. Many people on the other hand seem to consider the lowest “regular ISO” to be the “base ISO”. FWIW, usually the image sensor is driven with the same parameters in both cases.
ISO value itself is really a property of output formats, like JPG.
IMHO the concept of base ISO should be abolished for above reasons. It’s likely more harmful than useful for beginners.
Iso causes noise. Stop spewing the Bs northrup Invents.
Ultra bright outdoors, shoot at 1/4000 f22 iso 26000 it will be noisy. And don’t give me the “1/4000 f22 makes little light hit the sensor, it’s lack of light”
Lack of light makes you use high iso to expose correctly, therefore noise. Of course.
Oh for crying out loud.
Difficulty: He didn’t invent that, he literally parroted it.
OK - I won’t.
Little green men from Mars caused the noise!
OR… it could just be Signal vs Noise and if you do not have enough signal you will have noise… and all the signal you will ever have is gathered before ISO is applied.
Thus it is proved - all the noise is also gathered before ISO is applied.
You realize you just reversed your position, right? Lack of light does indeed force you to use high ISO, and that lets you see the noise that was already there.
Use that same low light scenario. Shoot at iso 100. And you get a perfectly clean black exposure.
See, low light, no noise. So low light doesn’t equal noise.
Boosting iso to get the exposure right when there is a lack of light. Does, as you expose the noise too
I wasn’t going to get involved in this one as well but here we go.
In this scenario, if you kept the ISO at 100 but instead of increasing ISO, you kept the shutter open for longer, you will also get a perfectly exposed image with minimal noise. If noise was inherent to low light scenarios, you would be capturing more of it because your sensor would be exposed to that noise for longer, but that’s not the case.
And yes, you would still get a small amount of noise (and hot pixels), but that’s thermal noise from keeping the photovoltaic sensors exited for a longer period of time.
From an electrical engineering perspective, you’re both right.
ISO in digital sensors is an amplification of the analog signal output by the photovoltaic sensor before it is converted to digital. Amplifiers indiscriminately amplify both noise and your signal of interest. In that sense, he’s right that a high quality sensor with little inherent noise will produce a less noisy image at high ISO than a low quality sensor with a lot of inherent noise. A high ISO (amplification) will serve to amplify noise existing in your signal.
However, amplifiers also have a quality known as “noise figure”, in that all non-ideal amplifiers will add some noise to a signal. So you are also right in that there is some amplifier added noise that is possibly more visible when you increase your ISO, because amplification tends to reduce your maximum theoretical dynamic range through the additive noise, not increase it.
All that being said, this is all semantics and in practice I think the comment you’re replying to is correct, but is a bit loose with some technical concepts that don’t really matter in practice.
So is it better to have iso at auto
If Auto will do it for you - sure. Remember that you’re not hurting anything by shooting at the ISO the shot needs, and on older, variant sensors you don’t hurt yourself in post by shooting at too low of an ISO, which can end up giving you even more noise when you correct those shots in post.
There are times when pushing in a bit of Exposure Compensation is needed, some amount of -Ev to defend against blowing out your highlights or the opposite, dealing with backlit scenes where you need more ISO and +Ev than auto wants to give you.