Best ISO?

takinmore

this is likely a silly question in todays digital world but I am unclear so here goes.
When I shot film decades ago, I always preferred ISO 25 film - I just liked it and I had better luck making large prints.

Today with my D70s, I have so far stuck with ISO 200 (lowest I can get) based on that old belief that it is better.

Is it?

I know the higher I go with ISO the more noise I get, I understand the mechanics but am wondering, do you experts out there really care about the low end ISO to get the absolute best print or does it even matter anymore? I know enough to go with higher ISO when needed, I am talking about when you have the option to shoot at any ISO (and obtain the desired result with your aperature and/or speed) do you choose the lowest possible because it will be arguably better? Or not?

thanks

D'Buggs

If the option presents, (I) always go with the lowest ISO..... Noise degrades, unless, of course, it (noise) is a corporation of the intended image. Shutter speed and DOF are the ruler; If I can't get the exposure I want, only then do I bump ISO.

That's my opinion, anywho....

GadgetRick

With today's dslrs, you can easily shoot at higher ISOs with little to no noise...as long as you properly expose the image. A lot of people still hold out lower is better--and I'm guessing it is--but I don't believe it's as critical as it may have been with film (I didn't shoot a film slr).

I'd just play with various ISO settings and see what you get from your camera.

JohnBiggs

I have read (but not confirmed) if you go lower than the normal ISO (ISO expansion) that image will degrade too. 100 or 200 is going to be ideal. 400 is hardly noticeable. 800 and above is still very good but it will become more noticeable depending on the camera.

angevin1

takinmore wrote: »

this is likely a silly question in todays digital world but I am unclear so here goes.
When I shot film decades ago, I always preferred ISO 25 film - I just liked it and I had better luck making large prints.

Today with my D70s, I have so far stuck with ISO 200 (lowest I can get) based on that old belief that it is better.

Is it?

I know the higher I go with ISO the more noise I get, I understand the mechanics but am wondering, do you experts out there really care about the low end ISO to get the absolute best print or does it even matter anymore? I know enough to go with higher ISO when needed, I am talking about when you have the option to shoot at any ISO (and obtain the desired result with your aperature and/or speed) do you choose the lowest possible because it will be arguably better? Or not?

thanks

Dynamic range is tied to ISO and contrary to what we might think, it is not (always) found at the lowest ISO...The link is helpful, but not what I was looking for...Ziggy53 Knows this chart to which I speak...I lost it though.....ZIGGY!

http://www.dxomark.com/index.php/eng/DxOMark-Sensor

Edit: Looks like I might have mispoke!! Click this link and Choose yer poison, er camera! : http://www.dxomark.com/index.php/eng/Image-Quality-Database

jfriend

In a digital camera there are several main image quality properties that are related to ISO. Obviously everyone knows about noise. On a given sensor, the higher the ISO, the more noise is visible. That's because the higher the ISO, the less photons strike the sensor and the lower the signal-to-noise ratio is and thus the more visible the noise is.

For that same given sensor, the opposite is true too. The more photons you give it, the lower the visible noise will be. That means if you have a camera like the Nikon D300s with a base ISO of around 200 and you turn it down to ISO 100, you can reduce noise even further.

However, setting a camera to something below it's true base ISO has other compromises. It potentially clips highlights and reduces the dynamic range that you can record. This is because the way ISO 100 works is it overexposed by about one stop, then digitally reduces the resulting image data by one stop to try to make it normal again. This is wonderful for the shadows because they get one more stop of exposure than they would normally (decreasing noise), but it's horrible for the highlights because in a full dynamic range scene, overexposing by one stop will clip a stop of highlights. Once clipped those highlights are typically not fully recoverable with software. Thus, the potential dynamic range that you can capture at this reduced ISO is compromised.

The true base ISO for a camera is the ISO at which the sensor data is not amplified (up or down) in any way. It's just digitized and then recorded as the image. Rumor has it that the D300 has a true base ISO of around 160, not 200 - though the difference between the IQ at those values is fairly small.

Thunder Rabbit

Howdy.

For some very good information on noise, click here.

takinmore

thanks everyone, some helpful data here.

Seems my old instincts are essentially correct, go with the base ISO unless there is a need for a higher one and don't worry too much until it passes 800 (even then, depending on the camera and the needs of the assignment)

cheers!

Andy

The DXO link is a good one. It confirms what many of us know already - in today's top quality cameras, certainly up to ISO 400 makes no perceived difference under most circumstances.



and the other indicators (tonal range, etc) all are very close from 100-400 iso on a Canon 5D II.

A long time ago, Canon told me ISO 200 was their "native" ISO - to Jfriend's point - that ISO at which there's no sensitivity adjustment either way on the sensor. DXO's charts seem to lead me to believe it's around ISO 160, but 200 works Shooting at 200 or 400 ISO also buys you 1 or 2 stops faster shutter speed, most useful in handheld situations.

Hindsight

The "best" ISO, as was mentioned, is simply that which provides the best dynamic range at any given exposure. A well exposed shot with some noise is generally preferable to an under exposed shot. It's always better to have too much than too little in terms of material to work with in post. And besides -NR software now days is a wondrous thing.

JohnBiggs

Andy wrote: »

The DXO link is a good one. It confirms what many of us know already - in today's top quality cameras, certainly up to ISO 400 makes no perceived difference under most circumstances.



and the other indicators (tonal range, etc) all are very close from 100-400 iso on a Canon 5D II.

A long time ago, Canon told me ISO 200 was their "native" ISO - to Jfriend's point - that ISO at which there's no sensitivity adjustment either way on the sensor. DXO's charts seem to lead me to believe it's around ISO 160, but 200 works Shooting at 200 or 400 ISO also buys you 1 or 2 stops faster shutter speed, most useful in handheld situations.

Two things. The Orange Dots represent the cameras ISO 'stops' so the mark at about 160 is ISO 200 on the camera. If you hover the Dots on the DXO website it will show this. The first dot at about ISO 73 is ISO 100 on the camera wheel. You don't really get fall off until ISO 800 which is what was stated before.

Second, Always shoot at the full stops for ISO. If you need a 1/3 stop use aperture or shutter. The cameras are optimized for these full stops, and it has been shown in the past that 1/3 stops on ISO can perform worse.

jfriend

JohnBiggs wrote: »

Second, Always shoot at the full stops for ISO. If you need a 1/3 stop use aperture or shutter. The cameras are optimized for these full stops, and it has been shown in the past that 1/3 stops on ISO can perform worse.

If I recall, the idea to only use full stops is something that has been shown with Canon, not Nikon. I don't know if this is still true on Canon's latest cameras or not. This is most relevant with auto ISO which uses partial stops of ISO all the time.

JohnBiggs

jfriend wrote: »

If I recall, the idea to only use full stops is something that has been shown with Canon, not Nikon. I don't know if this is still true on Canon's latest cameras or not. This is most relevant with auto ISO which uses partial stops of ISO all the time.

It's easy enough to avoid with any camera if no one is 100% sure.

jfriend

JohnBiggs wrote: »

It's easy enough to avoid with any camera if no one is 100% sure.

It is not possible to avoid the intermediate steps when using auto-ISO (because you don't control the ISO setting) which is really, really useful for marginal light sports shooting.

JohnBiggs

jfriend wrote: »

It is not possible to avoid the intermediate steps when using auto-ISO (because you don't control the ISO setting) which is really, really useful for marginal light sports shooting.

I'm not quite sold on the need for auto ISO. But yes, I'm sure all kinds of problems can crop up when letting the camera decide anything automatically.

Shutter speed
Aperture
White Balance
Focus Points
Exposure
Flash power

All can produce less than desirable effects.

jfriend

JohnBiggs wrote: »

I'm not quite sold on the need for auto ISO.

Ahh, you must not shoot sports in variable moderate or low light. When you are at full aperture, need a fast shutter speed (e.g. 1/1000), the lighting is low to moderate and variable (either varies across the field or clouds/sun movement are making it vary with time), then auto ISO gives you the lowest possible ISO that works with your selected aperture and required shutter speed. It's awesome for sports in these conditions.

You don't have time to adjust the ISO for every shot (or even during a sequence as the lighting changes). So, without auto ISO, you are forced to crank in some reserve ISO so that the light meter has room to work on both sides (if it gets lighter or darker). In that case you end up shooting a higher ISO than is required.

Auto ISO prevents that. I put the camera in Aperture priority. I turn on auto ISO. I set up auto ISO to have a minimum shutter speed of 1/1000 and the camera automatically adjusts the ISO to just get me my minimum shutter speed and a proper exposure. I get the shoot at the lowest possible ISO to give me the shutter speed and aperture I want. It's quite sweet. I wouldn't use it for a landscape or portrait where I have time to manually think about and select the optimal settings for a particular shot, but in cases where you don't have that opportunity, it works great.

GadgetRick

Auto ISO is great...when implemented properly. The problem with Canon (at least on the 50D) is it's implemented horribly (unless I'm missing something). You can't set thresholds for the various settings so you truly are at the mercy of the camera.

But, when it's working properly, it's very cool because it can select an intermediate ISO (like 725) rather than going to 800. You can't manually select that setting but the camera can do it for you. Very cool....

jfriend

GadgetRick wrote: »

Auto ISO is great...when implemented properly. The problem with Canon (at least on the 50D) is it's implemented horribly (unless I'm missing something). You can't set thresholds for the various settings so you truly are at the mercy of the camera.

But, when it's working properly, it's very cool because it can select an intermediate ISO (like 725) rather than going to 800. You can't manually select that setting but the camera can do it for you. Very cool....

I don't know Canon cameras, but Nikon has a nice implementation of auto ISO. You set base ISO, max ISO and min shutter speed.

GadgetRick

jfriend wrote: »

I don't Canon cameras, but Nikon has a nice implementation of auto ISO. You set base ISO, max ISO and min shutter speed.

Yes, I recently switched from Nikon to Canon and went to use Auto ISO and, well, you can't set these things...at least I've not found any way to do so. It's a shame as I like Auto ISO for many things (I shoot a lot of sports).

JohnBiggs

jfriend wrote: »

Ahh, you must not shoot sports in variable moderate or low light. When you are at full aperture, need a fast shutter speed (e.g. 1/1000), the lighting is low to moderate and variable (either varies across the field or clouds/sun movement are making it vary with time), then auto ISO gives you the lowest possible ISO that works with your selected aperture and required shutter speed.

Nope, Sports are not a common thing for me to shoot so I don't know. When I shot sports in low light (gym) two weeks ago, I set max aperture and picked an ISO that put the shutter speed in the ballpark. Auto ISO sounds interesting for this too. And no, the gym didn't have consistent lighting as subjects closest to me were lit by indoor lights and subjects farther were lit by the open bay doors.

This worked for me, and I'm able to apply the same NR across all the images.

Vich

Great point Andy. Up to ISO 400 doesn't make a whole huge difference. Some; but not a lot.

In film days; ISO 200 was nearly interchangeable with 100 to the lay person's eye, but like the OP said; discerning eyes (say, a fashion magazine cover shooter) wouldn't be caught dead with ISO 200 (or maybe even 35mm no matter the ISO). I'm guessing anyway.

You're an amazing shooter. Would you use ISO 400 on some awesome landscape or would you get out the tripod just so you can take it down to 100?

Agreed on Low-Expansion decreasing IQ. It takes pixel peeping to tell but it's there.

Question on SNR (Signal to Noise ratio) and other categories of this tool:

1. These charts don't show the dark areas verses well exposed ones. I have found that more an issue in the later crop of DSLRs. My 7D is way cleaner at ISO 3200 but I see some noise in the underexposed areas even at ISO 400.

2. STN (Signal to noise ratio). One would think that less signal boost is needed on a better designed/sized individual pixel. Ergo the FF advantage. Does this chart take that into account?

In other words; at ISO 1600 a nice big 5D pixel (biggest in the Canon line-up) might just not require so much electronic boost (signal) as a 7D (much more compressed pixels).

Is this thinking right? Is there less "signal" per sq-cm when bigger pixels (ie: more collection lens coverage) are used? One would think so since each pixel's light is simply reduced to a digital footprint of numbers so, more pixels = more signal.

Andy wrote: »

The DXO link is a good one. It confirms what many of us know already - in today's top quality cameras, certainly up to ISO 400 makes no perceived difference under most circumstances.



and the other indicators (tonal range, etc) all are very close from 100-400 iso on a Canon 5D II.

A long time ago, Canon told me ISO 200 was their "native" ISO - to Jfriend's point - that ISO at which there's no sensitivity adjustment either way on the sensor. DXO's charts seem to lead me to believe it's around ISO 160, but 200 works Shooting at 200 or 400 ISO also buys you 1 or 2 stops faster shutter speed, most useful in handheld situations.

chrisjohnson

takinmore wrote: »

this is likely a silly question in todays digital world but I am unclear so here goes.
When I shot film decades ago, I always preferred ISO 25 film - I just liked it and I had better luck making large prints.

Today with my D70s, I have so far stuck with ISO 200 (lowest I can get) based on that old belief that it is better.

Is it?

I know the higher I go with ISO the more noise I get, I understand the mechanics but am wondering, do you experts out there really care about the low end ISO to get the absolute best print or does it even matter anymore? I know enough to go with higher ISO when needed, I am talking about when you have the option to shoot at any ISO (and obtain the desired result with your aperature and/or speed) do you choose the lowest possible because it will be arguably better? Or not?

thanks

Great question - I too learned my photography using film and was pondering this.

My subjective experience using a 40D is that 100-200 ISO is best and this seems confirmed.

From the DXO data is seems that there is relatively little to be gained by upgrading the camera as long as I can take 90% of my pictures at 200 ISO or less.

Thanks to all the experts for your opinions.

The 48th Ronin

I think it’s all relative. When I shot weddings years ago with film I carried two 35mm cameras, one loaded with iso100 and the other with 400. I also had with me a Mamiya with two backs one with iso100 and the other with 400. I’d shoot iso100 if I could but if I needed a faster shutter speed or a little more dept of field then I went to the 400.

These days I shoot a lot of low light photography. Take for example this picture http://www.briancareyphotography.com/The-Great-Outdoors/Night-Lights/12161517_WDaKh#867443359_6vnVV I had to increase the iso on my 5D2 until I got the shutter speed I needed to still the boats. Had to go to iso2000 and got it with a 0.5 sec ss. Been down this road before and don’t want to be making the same mistakes of being anal about the lowest iso available. I used to be like that but thankfully I’ve changed.

In my opinion the best iso is the (lowest) one that gets you the shot!

All the Best
Brian Carey
http://briancareyphotography.com/

pathfinder

Yup!!