ISO Settings

Zanotti · April 13, 2008

I have learned to adjust my ISO settings to get me the speed I want when shooting. Mostly sports, but sometimes inside as well.

Coming from film, I tend to use the film equivalents - ISO 100-200-400-800-1600-3200. I shoot a Canon 30D, so there are lots of choices between those, I just stick to those because I first learned photography using film.

Is there any reason to stick with the "classics"? What does using ISO320 actually mean?

Thanks,

Z

ian408 · April 13, 2008

ISO means essentially the same thing for fllm and digital. In the digital
instance, it refers to signal gain and the other, film's sensitivity to light.

The beauty of digital allows you to adjust the sensor's gain as needed.

ziggy53 · April 13, 2008

Zanotti wrote:

...

Is there any reason to stick with the "classics"? What does using ISO320 actually mean?

Thanks,

Z

There is a growing body of evidence which seems to indicate that the "between" ISO settings of many cameras are not calibrated and are simply "adjusted" from the primary ISO settings.

Worse, it would appear that the middle ISO "adjustments" of many cameras may compromise the overall tonality especially when an exposure bias (EC) is also applied.

I haven't seen anything "I" consider absolutely conclusive, but for me, I use full ISO settings of 100, 200, 400, 800, 1600 (and 3200), except on the 1D MKII where I often use ISO 1250. I use the "Exposure Compensation" (EC) with those full ISO settings to fine tune the exposure.

NeilL · April 13, 2008

ziggy53 wrote:

... I use the "Exposure Compensation" (EC) with those full ISO settings to fine tune the exposure.

Please, do go on!! This is just getting interesting. I know some people who, for example, with the 40D, prefer to use ISO 200 with +3 EC instead of ISO 100, and readjust in PP. Is this the kind of thing you do?

Neil

ziggy53 · April 13, 2008

OK, I had to search for this but the following is the best documented information I could find and it regards the Canon 1Ds MKIII and fractional ISO:

http://www.northlight-images.co.uk/article_pages/cameras/canon_1ds3_noise.html

While this article describes the effects of fractional ISO and noise, there are lesser studies which show a similar correlation with tonal purity.

It would appear that some cameras apply a less accurate mathematical algorithm to fractional ISO than to the calibrated full ISO settings.

ziggy53 · April 13, 2008

NeilL wrote:

Please, do go on!! This is just getting interesting. I know some people who, for example, with the 40D, prefer to use ISO 200 with +3 EC instead of ISO 100, and readjust in PP. Is this the kind of thing you do?

Neil

On the Canon 40D, ISO 100, 200, 400 all have similar dynamic range, with only a slight loss in detail and slight increase in noise as ISO increases. There is no practical reason to employ strong EC instead of full ISO steps.

The issue/problem is the fractional ISO settings.

ziggy53 · April 13, 2008

ziggy53 wrote:

On the Canon 40D, ISO 100, 200, 400 all have similar dynamic range, with only a slight loss in detail and slight increase in noise as ISO increases. There is no practical reason to employ strong EC instead of full ISO steps.
...

I just re-read my words and they are confusing.

I use EC to adjust for highlight and shadow when the normal exposure read by the camera is incorrect for the intended tonality of the scene.

I use full ISO settings to allow a full range of tones at a particular exposure setting.

NeilL · April 13, 2008

ziggy53 wrote:

OK, I had to search for this but the following is the best documented information I could find and it regards the Canon 1Ds MKIII and fractional ISO:

http://www.northlight-images.co.uk/article_pages/cameras/canon_1ds3_noise.html

While this article describes the effects of fracional ISO and noise, there are lesser studies which show a similar correlation with tonal purity.

It would appear that some cameras apply a less accurate mathematical algorithm to fractional ISO than to the calibrated full ISO settings.

Good read, thanks!

The theory is certainly engrossing, but the practice is what ultimately matters and part of that is how much of a difference can be seen in images. Because of the theory, though, I have turned off fractional ISO and so now have to experiment with EC adjustments.

What routine do you apply, ziggy? Is it +2 or +3 EC and correct in PP?

Neil

NeilL · April 13, 2008

We seem to be out of phase a bit, ziggy, hehe!

The idea I'm trialing, is to use the sensor adjustment for full ISOs plus + EC to produce a net lower ISO as a way to circumvent the camera's software produced fractional ISOs which result in more noise etc.

Have I got the bull by the right body part?

Neil

ziggy53 · April 13, 2008

NeilL wrote:

...

The idea I'm trialing, is to use the sensor adjustment for full ISOs plus + EC to produce a net lower ISO as a way to circumvent the camera's software produced fractional ISOs which result in more noise etc.

Have I got the bull by the right body part?

Neil

The approach I use is to set the exposure using full ISO stops as appropriate, fine tune the exposure using fractional f-stops and/or shutter speeds, and then adjust the middle tones using EC adjustment if necessary. It is generally preferable to shoot with the highlights to the right in the histogram, but sometimes the highlights need to be protected as well.

If a scene has very wide dynamic range, I try to capture as much tonality as possible in the primary exposure, bracket if possible or if needed, and then adjust in post-processing using any number of techniques including Levels, Curves, Shadow/Highlight compensation, multiple layers and masks, HDR techniques, etc., etc. ...

georges · April 13, 2008

not following...
Ziggy - I'm not following on the use of the use of exposure comp...

I know that you know it's not a magic fourth variable. Changing exposure comp will adjust ISO, aperture or shutter speed.

On my Pentax, for example, EC will change aperture or ISO if the camera is in shutter priority. The specifics of which it changes depend on the selected program line and if auto ISO is enabled.

So I'm a little confused about what you're trying to say when you were comparing the use of EC vs. changing the ISO.

Not arguing with you, I just don't understand what you're saying.

Thanks, gs

ziggy53 · April 13, 2008

georges wrote:

Ziggy - I'm not following on the use of the use of exposure comp...

I know that you know it's not a magic fourth variable. Changing exposure comp will adjust ISO, aperture or shutter speed.

On my Pentax, for example, EC will change aperture or ISO if the camera is in shutter priority. The specifics of which it changes depend on the selected program line and if auto ISO is enabled.

So I'm a little confused about what you're trying to say when you were comparing the use of EC vs. changing the ISO.

Not arguing with you, I just don't understand what you're saying.

Thanks, gs

You are correct.

EC is basically a "shift", one direction or the other, of exposure values. The type of shift depends on the shooting mode of the particular camera.

EC does not do anything that you could not do yourself using the full manual controls of the camera. It does automate, to an extent, the exposure corrections required to properly represent a scene tonally when the automated exposure system of a camera is not likely to be accurate.

The classic example is of a snow scene where the subject of the scene is rather diminutive to the scene, but vital to the story of the scene. The camera meter will probably mis-read the scene's exposure in most metering modes, so an EC intervention is required.

Harryb · April 14, 2008

Zanotti wrote:

I have learned to adjust my ISO settings to get me the speed I want when shooting. Mostly sports, but sometimes inside as well.

Coming from film, I tend to use the film equivalents - ISO 100-200-400-800-1600-3200. I shoot a Canon 30D, so there are lots of choices between those, I just stick to those because I first learned photography using film.

Is there any reason to stick with the "classics"? What does using ISO320 actually mean?

Thanks,

Z

From Thom Hogan - "I know a lot of photographers who just set their cameras on what they think is the highest acceptable ISO (or set Automatic ISO to that value). Simply put, you're leaving pixel quality on the ground when you do that. The base ISO value for any camera is where it gets the most dynamic range, least noise, and highest image quality, period. The closer you are to that, the better your pixels will be. Don't bump up the ISO unless you absolutely need to. That's not to say that you can't bump ISO, but make sure that you have to. "

Photoskipper · April 14, 2008

I am old school boy, stick to ISO 100 if possible. Constantly under-exposure -1/3 step as I was taught to get the greatest detail with such setting during the film era.
After using the 5D, due to the good noise control of high ISO, I have tendency to put the ISO upto 640 when the light is too dim. But just feel the ISO 400 is the upper limit for most of situation. So far the ISO 1200 in the 5D is still acceptable.
For 300D, the photo above ISO400 has too much noise.

Icebear · April 14, 2008

You people crack me up. All this talk about the "film era" and all. Heck I remember Kodachrome 25, 50, 64, etc. We thought Ektachrome 160 was fast as hell. They came out with this "faster" B&W film called Plus-X which was cool, but Tri-X, fuggedaboudit - too grainy.

The other day at my grandson's b'day party, I was shooting my D300 at ISO3200 (just for giggles) and damn if I didn't get some decent images.

That being said, if I can shoot at ISO 200, I try to.

Zanotti · April 14, 2008

Photoskipper wrote:

I am old school boy, stick to ISO 100 if possible. Constantly under-exposure -1/3 step as I was taught to get the greatest detail with such setting during the film era.
After using the 5D, due to the good noise control of high ISO, I have tendency to put the ISO upto 640 when the light is too dim. But just feel the ISO 400 is the upper limit for most of situation. So far the ISO 1200 in the 5D is still acceptable.
For 300D, the photo above ISO400 has too much noise.

Then you have never shot HS football under the (dim) lights. ISO 3200 is the bare minimum if you want any keepers. Even then, its barely enough!

Z

Photoskipper · April 15, 2008

Just for the purpose of discussion. I wonder how useful of "fast lens" nowadays.
It is great to have the F2, F1.8 and even F1.4 lens but there is a big price gap to consider.
If we can use ISO1600, which is 4 steps faster. If I use a F4 with ISO 1600, will it be equivalant to ?? F1.4.
Or if I buy a 70-200 F4 with IS and use the ISO 800, I can gain 3 steps by IS and 3 steps from ISO, what is the point of paying extra 1K for the F2.8 lens.

Understand that there are many other considerations but just want to make people think a little bit.

NateWagner · April 15, 2008

Just for the purpose of discussion. I wonder how useful of "fast lens" nowadays.
It is great to have the F2, F1.8 and even F1.4 lens but there is a big price gap to consider.
If we can use ISO1600, which is 4 steps faster. If I use a F4 with ISO 1600, will it be equivalant to ?? F1.4.
Or if I buy a 70-200 F4 with IS and use the ISO 800, I can gain 3 steps by IS and 3 steps from ISO, what is the point of paying extra 1K for the F2.8 lens.

well, except for the fact that the person with the 2.8 will also be able to shoot high ISO thus adding those extra stops making theirs seem even faster as well.

With this in mind it seems that while shooting high ISO has it's advantages the advantages hold for each lens.

ziggy53 · April 15, 2008

Photoskipper wrote:

Just for the purpose of discussion. I wonder how useful of "fast lens" nowadays.
It is great to have the F2, F1.8 and even F1.4 lens but there is a big price gap to consider.
If we can use ISO1600, which is 4 steps faster. If I use a F4 with ISO 1600, will it be equivalant to ?? F1.4.
Or if I buy a 70-200 F4 with IS and use the ISO 800, I can gain 3 steps by IS and 3 steps from ISO, what is the point of paying extra 1K for the F2.8 lens.

Understand that there are many other considerations but just want to make people think a little bit.

Fast lenses and fast apertures are just as valuable as ever. IS will not eliminate the moving subject blur caused by a "slow" aperture resulting in a slow shutter speed. The combination of competent/usable high ISO, large aperture and resulting fast shutter speed will always have great value.

Factor in the extra aesthetics of bokeh and background/foreground control to isolate the subject, and you can see why large aperture is, and always will be, a coveted feature of advanced photography.

IS really only affects the use and need of a tripod, which will always be a more stable platform than IS except where the platform for the tripod itself is in motion.

claudermilk · April 15, 2008

Photoskipper wrote:

Just for the purpose of discussion. I wonder how useful of "fast lens" nowadays.
It is great to have the F2, F1.8 and even F1.4 lens but there is a big price gap to consider.
If we can use ISO1600, which is 4 steps faster. If I use a F4 with ISO 1600, will it be equivalant to ?? F1.4.
Or if I buy a 70-200 F4 with IS and use the ISO 800, I can gain 3 steps by IS and 3 steps from ISO, what is the point of paying extra 1K for the F2.8 lens.

Understand that there are many other considerations but just want to make people think a little bit.

Very useful indeed. Just having the built-in ISO adjustment doesn't change the need for fast glass. You had ISO3200 film and needed fast glass, how does setting an electronic sensor to an equivalent sensitivity make any difference? Trust me, fast glass is as necessary as ever (don't believe me? Look at my site--half of it wouldn't exist if not for fast glass + ISO 3200). Like ziggy said, IS does not stop subject motion--I know we've pointed this out to you before; it's a sometimes useful tool, but is certainly not the magic bullet some people think it is.

Another thought, the film-era practice of underexposing is not really applicable to digital. All that's doing is adding 1/3 stop of noise you wouldn't otherwise have had. Expose for the highlights, not the shadows in digital.

Robinivich · April 15, 2008

For myself, when light allows I'll keep it at ISO 100, but I consider 100-400 to be the "no serious consequences" range on my XT and 40D, and based on the shutter speeds I need I often shoot at 400

This isn't to say that I don't use 1600 or even 3200, just a week or so ago I shot a night time lit field soccer game at f2.8 and ISO 3200 and still had to deal with some motion blur at 1/400s (grrr). These are not 100%-crop-friendly situations, but if it makes the difference between picture or no, then that's what has to happen.

As concerns the partial stops, on my XT I didn't have the choice, I do now on the 40D, but with this as well as F-stops I always find myself using whole stops (my brain doesn't allow 1/3-stop adjustments

). My understanding is that ISO 320 et al. is just the camera exposure correcting ISO 400 or 200, and I can manage that myself later. Not to mention that for the difference between 1/100 and 1/125 of a second, I'll stick with whole stops and actual sensitivites, thank you very much

thebigsky · April 15, 2008

This is a really interesting thread, I've always had a natural aversion to the 'inbetween' ISO's but could never explain why.

Since having a Canon 5D I've always been happy to shoot up to ISO 800 providing a I get the exposure correct, and sometimes quite like the grain introduced at this level and higher.

However I wasn't aware that the dynamic range was affected. Is it true therefore that even with my well exposed images at ISO 800 there is considerably less dynamic range in the image than if I'd shot it as ISO 100?

Charlie

ziggy53 · April 15, 2008

thebigsky wrote:

... Is it true therefore that even with my well exposed images at ISO 800 there is considerably less dynamic range in the image than if I'd shot it as ISO 100?

Charlie

There is reduced dynamic range at ISO 800 versus ISO 100. I would not characterize it as "considerably less". Depending on the subject it may not be visible except in subjects and scenes which require a very wide dynamic range.

The Canon 5D already has one of the widest dynamic ranges of any camera on the planet, partly due to the relatively low pixel density and partly due to the imager design, low noise and high quality amplifiers and a very competent image processor.

ISO 800 on the Canon 5D is still pretty respectable in terms of both random noise and dynamic range. It is a measurable deviation from ISO 100, but still extremely usable.

thebigsky · April 15, 2008

Thanks Ziggy, great information as always

Charlie

KED · April 15, 2008

ziggy53 wrote:

OK, I had to search for this but the following is the best documented information I could find and it regards the Canon 1Ds MKIII and fractional ISO:

http://www.northlight-images.co.uk/article_pages/cameras/canon_1ds3_noise.html

While this article describes the effects of fractional ISO and noise, there are lesser studies which show a similar correlation with tonal purity.

It would appear that some cameras apply a less accurate mathematical algorithm to fractional ISO than to the calibrated full ISO settings.

This has been bugging me all day. While the results of the referenced test seem to speak for themselves, if it's true that the fractional ISOs produce inferior results, why on earth would manufacturers -- I know Canon and presume Nikon -- install 'tweeners as default settings?

ziggy53 · April 15, 2008

KED wrote:

This has been bugging me all day. While the results of the referenced test seem to speak for themselves, if it's true that the fractional ISOs produce inferior results, why on earth would manufacturers -- I know Canon and presume Nikon -- install 'tweeners as default settings?

There have been other, less formal, tests that seem to verify the problem with fracional ISO exists in many entry level cameras as well.

Marketing is the reason most manufacturers do anything.

gtc · April 15, 2008

Iso
my rule of thumb is (on my 20D )

ISO100 for bright sunshine/flash and macro, and anything else shot from a tripod

ISO 200 for handheld cloudy /overcast/shade and for fast moving subjects,like bats and birds etc.

ISO400 for reasonably bright indoor light and faster moving outdoors subjects(cars and planes) or when substantial stopping down is required for hand held shots requiring lots of DOF.

ISO 800/1600/3200 for anything else where I can't get a fast enough shutter speed.I also like ISO 800 for its Velvia like colour rendering.

I don't like ISO 3200 much however have found that I can live with it in B&W.If you want the shot then you will use it...

sparkyphotog · April 16, 2008

Auto ISO?
I recently "discovered" the auto ISO setting on my DSLRs (a Nikon D70 and D80). I was getting sick of switching ISOs all the time. Hey, anything I can do to make shooting easier, I'll take it. I can focus on what I'm shooting and not on the **** camera. So, I can set Auto ISO to kick in when the shutter speed falls below a specified value. I use VR lenses most of the time, shooting hand-held in available light, so I chose 1/30. I set my cameras to their lowest ISOs, and aperture priority mode, and off I go. I find myself getting more and better captures because I'm not thinking about camera settings, but about what I'm shooting. Love it!

That said, I don't use this set up all the time. But it has become my "default" for everyday shooting.

KED · April 17, 2008

ziggy53 wrote:

Marketing is the reason most manufacturers do anything.

At the high end, it would be poor marketing to install 'tweener ISOs if they perform poorly -- nobody bought his or her 1DMkIII because it could shoot at 640 ISO. So as marketers of a "brand" they must think that 'tweener ISOs are beneficial, not detrimental.

(BTW I did have a pretty satisfying first-time experience with ISO 3200 under the lights, still used NoiseWare though).

Photoskipper · April 17, 2008

claudermilk wrote:

Very useful indeed. Just having the built-in ISO adjustment doesn't change the need for fast glass. You had ISO3200 film and needed fast glass, how does setting an electronic sensor to an equivalent sensitivity make any difference? Trust me, fast glass is as necessary as ever (don't believe me? Look at my site--half of it wouldn't exist if not for fast glass + ISO 3200). Like ziggy said, IS does not stop subject motion--I know we've pointed this out to you before; it's a sometimes useful tool, but is certainly not the magic bullet some people think it is.

Another thought, the film-era practice of underexposing is not really applicable to digital. All that's doing is adding 1/3 stop of noise you wouldn't otherwise have had. Expose for the highlights, not the shadows in digital.

I totally agree with it. Digital is different from film. The major difference is that I can sit down in front of my PC to do the post-processing comfortablly, change the ISO in split second to meet the demand.

There are many more advantage of fast lens, freezing the moving object, reduce the DOF, improve the detail and contrast. I love the fast lens as well. But considering the price to pay, it is not for everybody. I would like to promote the digital photography as an affortable hobby for the general public. Sharing some alternative idea to help our fellow photographers to save some money and yet enjoy the hobby.

The new technologies - fast lens, extreme fast ISO, new processor and software allow us to push the limit much further.

May be one day in future, we don't need to care about the ISO. Anyway the sensor captures the digital signal as original then we can do whatever necessary in the computer.

ziggy53 · April 17, 2008

KED wrote:

At the high end, it would be poor marketing to install 'tweener ISOs if they perform poorly -- nobody bought his or her 1DMkIII because it could shoot at 640 ISO. So as marketers of a "brand" they must think that 'tweener ISOs are beneficial, not detrimental.

(BTW I did have a pretty satisfying first-time experience with ISO 3200 under the lights, still used NoiseWare though).

The fractional ISOs are not terrible. Most people will never see the reduction in quality. Few will measure the reduction in quality.

If I had a "need" to use fractional ISOs I would be concerned. Not a biggee IMO.

ISO Settings

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