gessman Loc: Colorado

Bless you, I don't mean to sound abrupt or unkind but this question cannot be answered here - there is neither time nor ability to reach a comprehensive, conclusive answer from 72,000+ people who are not of one mind even if there is only one answer. Why, we even have some people here who are willing to tell you everything they know even though many of them lack the capacity to know anything.

What you're asking is, "is it better to have a bad picture of a good subject, a good picture of a bad subject, or some compromise in between." That's your decision and you have to make it, preferably based on a lot of experience and study which allows you to properly assess a scenario in advance in terms of your capabilities which includes just you, mother nature, and your equipment. What you're going to get here is a repeat of the parable of "The Blind Men and The Elephant" (Google/Wikipedia) but you won't know that because you do not have the vision, capacity, or need to put the pieces you currently have together or you wouldn't be asking the question.

You have to know enough to decide if you want to be a practical person who comes away with the best shot under the circumstances and a willingness to accept it knowing that you've done the best job possible for you, given your knowledge, skill, and your equipment levels, or if you're going to insist on doing it a certain way that causes you to miss a lot of shots that you could otherwise get with a little willingness to compromise being an anal "procedurecrat." It IS your choice. Have the confidence to make it, experiment, and learn from your mistakes which, incidentally, you shouldn't openly display like so many of us do. Obviously, it'd be fantastic if we always got excellent high quality shots of very exciting subject matter, but that's not likely to happen all that much, unarranged, especially if we shoot everything that comes down the pike, still or moving.

My personal philosophy is to get the best shot possible given the circumstances even if it pushes my iso up to as much as 6400 and worry about fixing it later, again, to the extent I can. I'm pretty happy with most of my shots but then, I don't do this to put shoes on the kids, or buy bread, or even beer. Please feel free to check my shots out here by referring to my profile and looking at my last few threads posted if you care to see what about my shots makes me happy. http://www.uglyhedgehog.com/user-topic-list?usernum=1324.

Reinaldokool Loc: San Rafael, CA

In principle the low ISO does produce less noise. Every amplification amplifies noise as well as signal.

However, the latest up to date sensors are amazingly noise-free. At a practical level, I can get essentially noise free performance from my Sony a6300 up to ISO 3200. It is noiseless enough to satisfy even some nit-pickers. It will get to 6400 and even 12,800 without serious issues--except in swatches of clear, night sky.

So hypothetically, shooting low ISO is better, and that was true with older sensors. Not so much with newer ones.

Apaflo Loc: Anchorage, Alaska

bclaff wrote:

First let's be clear, high ISO settings don't introduce noise.
Noise is more apparent when the Signal to Noise Ratio (SNR) goes down ...
...
This reasoning is behind the fact that many photographers (at least that I know) shoot in manual mode at native ISO with ISO Auto turned on.

Two very astute statements that need to be emphasized and should not be ignored. The first is the fact and the second is how to apply it in practice.

Djedi

Very much agreed. Here's an aerial shot done at ISO800 (f5.6, 1/4000), taken with a D7100. The full res closeup is from the lower right. The entire photo would be about 48" wide.
Just an example of how ISO 800 won't always be a problem.

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James Slick Loc: Pittsburgh,PA

gessman Loc: Colorado

I certainly don't want to appear to be disagreeable but the second of the two "astute statements" seems to raise a couple of questions. I saw somewhere back about 2009 that my Canon 5d2's native iso was 160 and I would be well served to shoot at multiples of that, 320, 640, etc... Now comes my Sony a6500 and some person named Michael Zhang at a site called PetaPixel has come along and said the a6500 has a native iso range, "The native ISO range is 100 to 51200." Now, how's a dumb ol' guy from Arkansas s'posed to make any sense out of that and the "astute statements" at the same time. Being a long suffering hobbyist, I mostly just shoot and don't pay a lot of attention to all the technical stuff but somehow I's thinking that "native" iso was a single number, a low number like 100 or 160 and not a range but I may have been thinking about a "base iso." If a "native iso" is 100 and you shoot with auto iso enabled, which would theoretically allow the iso to float up on each shot, how can you be shooting at the native iso? Wouldn't we need to be talking about shooting within the native iso range or is PetaPixel selling us down the river?

bclaff Loc: Sherborn, MA (18mi SW of Boston)

"Native" ISO is a confusing subject. It's generally the highest ISO setting that has the lowest analog gain applied inside the camera.
Often that's the lowest ISO setting excluding "extended" ones, but there are exceptions.

For your Canon EOS 5D Mark II ISO 160 is a good choice but actually ISO 100 could also be considered native.
Canons screwy treatment of intermediate ISOs has always confused this issue.

For the Sony ILCE-6500 it's ISO 100; period.

There is never a range of native ISO settings, but more and more often you will see two rather than one.
Dual conversion gain technology makes the pixel behave in two different ways each with it's own native sensitivity.
For these cameras I would say there are two native ISO settings. (This can be a nuisance to those who use ISO Auto)
An example of such a camera is the Sony ILCA-99M2; one native ISO at 100 and the second at ISO 500.

Djedi

Well, you see gessman, obviously you have not been clued in to the new-age "alternate facts", which exist for the purpose of backing up a certain point of view or marketing requirement.

James Slick Loc: Pittsburgh,PA

By Gum!, In my day, if you wanted​ to know the base ISO of your​ camera you looked at a litte cardboard square in a frame on your camera back! If you needed to change it on the fly, you'd lose a few frames of the current one,but dammit, that was they style in those days...and we liked it!

Djedi

Ha ha ha! Yeah, I can relate.

bclaff Loc: Sherborn, MA (18mi SW of Boston)

Often when a range is cited it's the range of ISO setting for which only analog gain is applied by the camera electronics.
For the ILCE-6500 from DxOMark numbers I judge that as ISO 100 to ISO 6400. (I haven't got A6500 measurements of my own yet.)
Beyond ISO 6400 appears to be digital scaling.

mrpentaxk5ii

look at it this way, if you can't get a fast enough shutter speed for the subject you have 3 options. one: you can increase ISO until you get to the proper shutter speed. Two: you can induce light, not always easy to do. Three: do nothing and go home. for me I rather have a sharp photo with a little noise than a blurry one that is worthless or no photo at all, it's your choice, take your pick.

Apaflo Loc: Anchorage, Alaska

There are four options. The first should be to use a wider aperture.

mrpentaxk5ii

We are not robots, people think differently and to judge people that you have never met is a poor trait. Noise, most people don't want it in a photo but with the cameras that we have today to shoot at ISO 200 or less is silly. Look at the photos posted on U.H.H people shoot from 100 to 1600 ISO depending on light and subject every day, but if you want to stay at 200 or less that is your choice you will miss out on a lot of photo ops. The photo of my friend in his kayak was taken at F-10, ISO 400 120mm with a Pentax Kr. The eagle was taken also with a Pentax Kr at 1/4000 sec ISO 1600 at 400 mm, both photos were taken with a sigma 120 - 400 mm 4.5-5.6. photo was slightly cropped. The camera is an APS-C 12 MP, this is not high end equipment, I have replaced this camera with a Pentax K5ii as my main camera, if I can photograph an eagle from a kayak with this camera at ISO 1600 you should be able to do the same with a Nikon 810.

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mrpentaxk5ii

So right, missed that one