High Iso or Low Iso?

[poider]

Just curious, as a quick example, I take photos of many subjects, I have no specialty, I lean toward Landscape, Architecture and Sea scapes with occasional forays into astro photography and Night scenes, But Generally I just love to take photos.
For general photography covering most subjects which would be the better option.......?
ISO 200 - 56000
or
ISO 50 - 12600

assuming all else was the same EG sensor size lens aperture etc?

Peter

[John King]

Peter, the general rule is always to use the lowest ISO possible.

This ensures that the greatest number of photons possible are captured by the sensor, maximizing the signal to noise ratio.

[ricktas]

Agree with John.

Always use the lowest ISO possible in any given situation.

[bitsnpieces]

I have a friend who takes the above advice to the extreme

He will always shoot on the lowest ISO possible, or around 100-200 max.

He'd rarely prefer blurry or dark photos, than photos with noise, because noisy photos don't look nice.

So as they say, pick your poison

[arthurking83]

Peter, the general rule is always to use the lowest ISO possible.

....

I don't think that's what Peter was asking!(assumption on my part here tho).

What I think the question was asking is: better to use a higher range or lower range?

(ie. range, not value)

From memory the D7200 native ISO range is 100-25600, so it's best practise to use the native range, rather than the ISO values labelled Lo and Hi.

Reason is, that the Hi and Lo ISO values aren't actual ISO values as such.

as an example. Technically the D7200 can do ISO 50, but it's not an actual ISO 50 value. What happens is that the camera shoots at ISO100, adapts it's internal values to mimic a 'correct exposure' to suit this ISO point, but it actually shoots at ISO, and then does internal processing to the image to alter exposure compensation of the image by 1Ev.

eg. lets say at ISO100(a native ISO value) you need 1/100 and f/2.8. but you set ISO to Lo1(ie. ISO50), the camera then recomputes the internal meter to show that exposure should be 1/200 and f/2.8, but at 1/200 and f/2.8 at ISO100, the image will be underexposed by 1Ev, so it then needs to process the image by +1Ev internally to create a properly exposed image.
This is why the ISO range has numbered values and the extended ranges(ie. Hi and Lo). Numbered values are 'native' which means no internal processing of the image with respect to exposure.

I tested this back when my D300 was new and from what I saw, non native ISO values(on the whole) couldn't recover shadow and highlight details as well(using Nikon software).
I don't remember seeing any ISO noise differences tho, just colour inaccuracy when trying to recover extreme tones if the need was required. In landscapes this can be more often than not. If the exposure is pretty much spot on, I never saw any differences tho.
Initially I used to shoot my D300 at Lo1, until I read an article explaining how the Hi/Lo ISO system works .. and then tested for myself.
Can't remember the exact differences in processing leeway it made, but something like 0.5Ev at the shadow end and 1Ev at the highlight end.
as a rough example,
if I shot at:
ISO200, I could recover -2Ev at the shadow end with little to no ugly recovery colour artifacts in the shadows and at least 1Ev, to 1.5Ev at the highlight end(usually clouds).
Lo1(ISO100 on the D300), shadows got ugly at 2Ev exposure compensation much more easily and I found it hard to want to use more than 1Ev, but 1.5Ev could be 'masked'.
The highlights used to 'posterise' at -1Ev using Lo1, but easily recoverable at -1.5Ev when using ISO100.

Haven't tested on the D800 or D5500, and the D70s only has native ISO settings.

So if you're setting up an Auto ISO range, I'd say stick with native ISOs with the caveat that Hi ISO range can be helpful sometimes too. (that is, avoid the Lo ISO points if the option is available)

I have my D800 set to 100 to Hi2(ISO25600). So ISO setting is ISO100(won't drop below that) and it will go to Hi2 if required.

[ameerat42]

I wasn't sure either. Besides that, I was thrown by the word "better".
So the only way your reply suits his query would be to avoid ISO50,
for the reasons you gave. But then, how does the camera treat values
higher than 100? Ie, is it any less invalid than for 50?

I know these are questions that arise subsequently, and may not be in the
OP's purview (< An arm-waving icon.)

[arthurking83]

....
So the only way your reply suits his query would be to avoid ISO50,
for the reasons you gave. But then, how does the camera treat values
higher than 100? Ie, is it any less invalid than for 50?

...

I just re read what I wrote, and it could be argued that I said "avoid ISO50"(or in a technical sense on the camera ISO Lo1) and it meant avoid at all costs.

I didn't mean it to come across in that way. That is, you don't need to 'avoid' ISO Lo1 at all costs, just be aware of what happens, and in an Auto ISO sense, it is best avoided.
The problem is that you never know how the entire tonal response in the image will come out, so there is always a possibility that some PP may be needed.
PPing an already processed image is a bit like double jeopardy (in a manner of speaking).

But there can be situations where ISO Lo1 may be a necessity, so it's use isn't without any merit.

Situations where ISO Lo1 may be needed are when you're maxing out shutter speed and have no other means to get an appropriate exposure, or that you want/need a particularly slower shutter speed for some reason.

One condition I never thought I'd ever experience photographically is max(ie fastest) shutter speed. On the D300(and D7200) that means 1/8000s.
Most camera makers give that option, even tho there is a very small possibility that most photographers will ever shoot at that shutter speed.

Yet I found myself once at 1/8000s and the image still over exposed by +2Ev .. couldn't recover the blown white highlights. So by that PP process, I needed more than 1/32000s shutter speed!
D300 was set to ISO Lo1(ISO 100) for those photos too. In my situation above, I wanted fastest possible apertrure(wide open), which at the time was f/1.2. Couldn't get it, so had to settle for f/1.4.

In the end, I got a 3 stop ND filter for that one time in 10 years where I need more than 1/32000 shutter speed 'ever again'.

So there may situations where Lo1 ISO could be used effectively.

ps. it's important to differentiate (at least on a Nikon camera) that ISO 50 or ISO100 or whatever is not the same as ISO Lo1(or Hi1 or Hi2).

it's a camera based thing. eg. D800 native ISO is ISO100 - (whatever) and ISO Lo is equivalent to ISO50. D810 has an ISO64 native, so ISO Lo1 = ISO32 in that camera.
So the important of distinguishing between numbered values and the extended Hi/Lo ISO values is important to note .. on a Nikon camera. Not sure how it all works on non Nikon cameras tho.

[ameerat42]

I see. "Extended" values are those to be aware of. Ta.

[John King]

Peter, the general rule is always to use the lowest ISO possible.

This ensures that the greatest number of photons possible are captured by the sensor, maximizing the signal to noise ratio.

As correctly qualified by Arthur, this advice must be applied with some caution to extended ISO ranges when they are present on your camera. Even within the same manufacturer's product line, extended ISO behaviour can be very different, one to the other.

For some examples from the Olympus stable ...

My E-30's base ISO is 200. When set to ISO 100 (extended ISO range), it gives far less noise (it's a bit of a noise machine ... ), but about 0.5 stop or so less dynamic range. It's a 2008 camera. Intermediate ISO steps are basically unusable due to how the ADC works in this camera.

OTOH, my E-M1 MkII also has a base ISO of 200, and the extended (low) ISO is 64. At this setting, the image is less noisy, and delivers about 1/3rd to 1/2 stop more DR. 2016 camera. Intermediate ISO steps work exactly as one would expect.

my E-M1 MkI also has a base ISO of 200, and the extended (low) ISO is 100. At this setting, the image is less noisy, and delivers about the same DR as at base ISO. 2013 camera. Ditto about intermediate ISO steps compared with my MkII.

There are lots of technical reasons for these differences, but way beyond the scope of the question, and the interest of most people.

So this advice must be used with caution, and must take into account your specific camera/s and how it behaves.

My advice given originally only applies to the standard ISO range for one's camera.

[swifty]

I'm just going to take it as that the OP is asking which is a more useful range of ISO for general photography (inclusive of the genres the OP has listed).
And that would be 50-12600 IMO. Beyond that, it really is a specialised range that few photographers will commonly shoot at.
And as has been pointed out above, these appear to be the extended ISO ranges (which carry further shooting implications) so in most cases, try to work and compare within the 'normal' ranges.
However, if you find yourself using eg. ISO 3200 to 12800 frequently the 200-51200 camera may be a better choice even if you don't shoot above ISO 12800.
It is all about how the camera is optimized and what your shooting habits are. Do you have a DAM software where you can pull up some statistics on what your most common shooting ISO ranges are?
Sorry I know you asked a simple question, but the answer rarely is unfortunately.

[poider]

Thank you all, I find I always use a relatively low ISO and have never willingly put it up past 3200.
I really like the idea of micro four thirds cameras and one day may get an Olympus OMD EM1 Mark 2, but am uncertain about the base ISO of 200 .

[swifty]

To give you an idea, my D700 also has a base iso of 200.
The main problem I’ve encountered is that using f1.4 lenses, I have on occasions hit my 1/8000 shutter speed limit. Not a big deal as I just stop down but I believe on the EM1.2, there might be an e-shutter that does higher than 1/8000. What limitations this mode has I’ve not researched.
When you can afford to maximise exposure, the lower real iso settings also allow the sensor to receive more light before the sensor saturates which for certain genres is a big plus. This generally applies to controlled environments like studio/still life photography or landscape (especially high DR scenes) and often on a tripod.

[John King]

E-M1 MkII has minimum mechanical SS of 1/8,000th. Electronic shutter is 1/32,000th. Sensor readout speed is 1/60th second.

[arthurking83]

I wouldn't use 50 ISO on the D7200(for the reasons already given).
And while it's best not to go into the ISO51K, area, sometimes you'd be better off in doing so if the need arises, rather than shoot at ISO25K limit risk the shot being under exposed and losing more detail.
With high ISO, always best to expose a bit brighter than normal without clipping important highlights. If colour is lost(almost certainly will!) ... at least you can do a monochrome PP and have something of the image if it's an important moment.

In fact, IIRC, the D7200 has an ISO102K setting available, but is only a monochrome setting too.
Oops! had to fact check: ISO51K and ISO102K settings are both monochrome only!

So change my comment to use the ISO range between 100-25600 for general duties.

.... there might be an e-shutter that does higher than 1/8000. What limitations this mode has I’ve not researched.
....

if it's anything like the D70/s, then probably of no real value. Could be different tho, as the D70 were CCD sensors, and CMOS are operationally different.
One of the handy aspects of the D70 cameras was that it could do flash sync at 1/500s, where even the top end models were limited to 1/250s(as they all still are).
But there was a catch. D70s shutter was for all intents an e-shutter. It's mechanical shutter was one of the cheapest devices Nikon could conjure up, and in reality limited to about 1/90s(apparently), the rest of the D70's shutter range was 'electronically controlled'.
(ie. up to 1/80s was all mechanical, beyond 1/100s it was partially mechanical(ie. open) and then gaited electronically giving up to 1/8000s.. quite high for a pretty low end camera!)
The idea seemed to be a great marketing tool for Nikon, but it had drawbacks. CCD are natively able to shut down the capture feed to the pixels all at the same time(hence why CCDs are no good for video).
So Nikon used that CCD 'limitation' to good effect(in terms of marketing), but in terms of high tech .. not as great as you'd think.
D70s was hopeless at shooting at super bright light sources(eg. the sun), due to this electronic shutter system.
The shutter had to be limited to below 1/80s to get an image that wasn't affected by 'sensor flare' or what's usually called 'sensor bloom' It looks like lens flare, but it's the sensor that produces it. Can't be controlled. Landscapes with the sun in the frame were usually affected by the issue.

I think I still have one image with this 'sensor bloom' issue, that I haven't zapped, but I remember a major cull of such useless images years ago.

One of the things I've wanted in a camera for a while now has been a well thought out e-shutter system, but more specifically electronic front curtain(ie. D850 is in my long term future for mainly that feature).
But I'm always weary of such features used to produce some silly marketing advantage such as ridiculous shutter speeds, just for the sake of higher numbers, and little in the way of technical competence.


.. anyhow .... what were we talking about? ..... AH!! ..... ISO range .... 100-25600

[John King]

Arthur, the fully electronic shutter in my E-M1 MkII allows it to shoot 60 fps in raw, among other things. The fact that it allows SSs of 1/32,000th is a by product of its existence.

Many other mFTs cameras also have electronic shutters.

One benefit that's often not appreciated is that they are utterly silent. No mirror slap and no shutter sound. Great for not spooking nervous wildlife (and humans ... ).

IOW , not a gimmick.

[Tannin]

Much useful information about many things in this thread. Well done all. I think we are all clear on the benefits of knowing your camera's base ISO, and clear that going below the base is quite pointless so far as improving dynamic range and noise is concerned. (But worth doing if, for example, you want to shoot a brightly lit scene at f/1.4 and have maxed out your shutter speed.) Various posters have provided details of the base ISO for various Nikon models, and John has done likewise for Olympus cameras.

So just to add my little bit - as I understand it, all Canon digital SLRs have a base ISO of 100. I'm pretty sure that there are no exceptions. Some Canon bodies provide a 50 ISO "fake" setting useful for Swifty's f/1.4 requirement, some don't.

Canon mirrorless would be the same, no doubt.I'm not sure what base ISO Canon P&S cameras use. The ones I am familiar with are also 100, but some of the ones with bought-in third-party sensors may be different.

[swifty]

if it's anything like the D70/s....:

As you've correctly stated, CCDs and CMOS operate very differently and I don't think you can infer anything from the D70/s.
Modern CMOS are closing in on not needing a physical shutter at all. One issue as John pointed out is the read speed which is 1/60 on an already speedy EM1.2 but will still subject you to the rolling shutter effect. The best of breed currently is in the A9, which I think Jim Kasson measured it to be around 1/160 which is approaching the mechanical shutter.
There are rumours the upcoming Nikon mirrorless may be e-shutter only. The holy grail of course would be global shutters but to be honest, if the read speed matches or exceeds mechanical shutters, it's good enough as long as there are no other penalties.

- - - Updated - - -

So just to add my little bit - as I understand it, all Canon digital SLRs have a base ISO of 100. I'm pretty sure that there are no exceptions. Some Canon bodies provide a 50 ISO "fake" setting useful for Swifty's f/1.4 requirement, some don't.

Unfortunately the fake or 'Lo' (Nikon speak) ISO settings doesn't help in the sunny situations because they are actually just ISO 100 (or whatever the base is) but the meter will let you meter as if it is ISO 50. So you don't actually gain any highlight room as the same exposure that might blow the highlights on the ISO 100 setting will do the same on the fake ISO 50 setting.
What it does however, is 'fool' the user into giving the sensor more exposure which in effect makes you expose more to the right (of the histogram) which results in better signal as long as you don't blow the highlights.
So no highlight headroom or DR gained, but usually some noise improvement by virtue that you will likely use an exposure setting that increases the SNR to the sensor.

[John King]

Swifty, the modern Olympus cameras shift the tone curve and slightly alter its shape for the extended low ISO setting. I suspect this helps IQ a bit. My E-M1 MkII has superior extended high ISO compared with my E-M1 MkI, by about one stop. Pretty significant in practice. Both are really RAW only above about ISO 8,000.

The old Olympus cameras (e.g. my E-30) played around with both analog gain (before the ADC) for full stop ISO settings, and digital gain (after the ADC) for the intermediate ISO settings. Fortunately the latter could be disabled in settings. That toying with digital gain was counterproductive! ISO 800 was far less noisy than ISO 500!!

[poider]

My E-M1 MkII has superior extended high ISO compared with my E-M1 MkI, by about one stop. Pretty significant in practice. Both are really RAW only above about ISO 8,000.

So, John I assume you are pretty happy with the E-M1 MkII, Would you (in your opinion) buy a 4 thirds sensor instead of a full frame, or does your Olympus back up a full frame? I am always reading that full frame is the only way to really get good photos but I am really drawn to the lightness and smaller size of the whole 4/3 system and also like the idea that many other 4/3 lenses can fit the Olympus.
I like to take my camera and as many of the accessories with me on vacation and presently half of my Nikon gear stays home.
I seems that with the Olympus System I can have the equivalent lenses and Accessories and take all of it with me.
Peter

[swifty]

Hi John, that’s good to hear. At least it helps a bit in the visual appearance of the highlight roll off but RAW headroom stays the same.
Have a look at photonstophotos’ PDR graph where it flattens in the extended low range.