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Why use ISO 100?
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Why do people use ISO 100? I thaught that ISO 200 was the setting for the least noise with noise increasing as you move up the scale. I am a Nikon user. Is a manafacturer thing? I have just looked a few of the landscape pics and a few of the more profesional looking ones seem to be taken at ISO 100. I know that I read somewhere that ISO 200 is the best setting and there is a reduction in quality when you go up or down from this setting.
Usually the lowest setting is the best, and on most cameras now it is
100, I think the norm used to be 200 if I am not mistaken. I would imagine
that there would be very little difference between 100 and 200 anyway.With canon the pro bodies are 50 iso as far as i know. nikons eq is 200. At that the quality is great.
but you have to lower settings to use if you like. but i never felt the need.
Sean.
ISO adjusts the sensitivity of the chip. By increasing the ISO setting, you ‘boost’ the signal from the chip, but you also ‘boost’ any noise that’s present. So, the higher the ISO setting, the more noise in your image. Personally, I hate noise, so I usually shoot at ISO 100 (the lowest my camera will go), but that often means that I have to shoot with slower shutter speeds, or wide apertures to get enough light to work with my low sensitivity ISO 100 setup.
With film, the size of the grain was / is used to determine the sensitivity to light. The larger the grain, the higher the sensitivity & also the higher the ISO / ASA rating. It works in a similiar fashion in digital. The higher the ISO rating, the grainier or noisier the results become, but different chips tend to handle noise differently. Larger sensors (as in full frame cameras) can handle noise / grain more & therefore can give better results in a same light situation than a camera with a smaller cropped sensor. The number of megapixels also affect the quality of the shots.
I believe the best iso to noise setting is manufacturer specific my D80 seemed to be less noisey at 200 and seemed slightly worse at 100 and 200 on the d700 seems to be optimal but going lower will yield a a very small small improvement.
The key thing is to use your best sensitivity to noise setting to get the best result those mountains are not about to go anywhere so motion blur is not an issue :)
The lower the ISO the more detail captured. Whether you’d notice the difference or not is debatable and depends on the size
of print etc….There is no best ISO, it depends on the situation and why you’re using it, ie high iso in low light gig photography can result
in really nice ‘grainy’ b+w images which might suit the event, but you may want iso 100 or lower for a portrait to ensure all the
detail is captured…The native iso of a camera is the best, in terms of colour accuracy, detail captured and minimal noise. Usually this is the lowest iso setting on a camera, but not always. The exception is when a manufacturer uses an sensor with a native iso of something like iso 200, but offers an iso 100 setting, for example. In this case, the iso 100 setting is not real, but rather using software/ shenanigans to simulate an iso 100 setting, much like when a camera goes to say iso 1600, but also offers a ‘high’ setting that is supposed to be the equivalent of iso 3200, for example.
Hope this helps. Low iso is better for the above reasons, but I wouldn’t let that stop you using the higher iso settings without hesitation. Often it’s a compromise on whether to opt for a higher iso to get a higher shutter speed, or stay at a low iso and risk having visible camera shake in your image as you may be forced to user slower shutter speed settings.
In the days of film, lower iso film usually meant better resolution, as grain was usually less. In later years, this was not always a given, with advances in film technology usually resulting in newer films having less grain and better resolution, even in comparison to lower iso films.
Thanks for that Damian, I just did a quick test on my 7D, and can see that the amount of noise can sometimes be reduced by moving UP to a native ISO from a lower ISO that isn’t. I guess every camera will behave differently then.
Hi Andy,
Not too sure about current camera models these days, as this was more of a trick by camera manufacturers when iso 200 was commonly the lowest iso setting on digital sensors. Most sensors now seem to start at iso 100, and reviews from sites like dpreview are a great source for quickly letting you know what the optimum qualities that can be expected from a sensor.
Forgot to mention also that slightly higher dynamic range is also a function of lower iso on digital, but for the exact benefits, you would likely need to check out the comprehensive tests carried out by some of the online sites
Damien’s post above summarises it well.
Every sensor has a native or base ISO. At this setting no amplification of the signal takes place (i.e. the gain on the sensor is not adjusted). Signal amplification induces noise and/or lowers the dynamic range. Additionally at native ISO, no software manipulation of the exposure would be applied in camera (some cameras have allow fake ISO values at both ends that don’t amplify electronically but actually under/over expose and then adjust in camera).
Unfortunately and surprisingly, camera manufacturers don’t make it obvious what the native ISO actually is and tend to round to 100 or 200 (Canon is 100, Nikon is 200). Testing of quite a few sensors has shown that the optimal performance is often closer to ISO 160 and if you set that value (or multiples of same 320, 640 etc) you might get the most noise-free results.
I use a Leica M9 and interestingly, the default ISO setting in that camera at 160 and the user interface kind of encourages you to use multiples of this number. The other manufacturers seem to use 100s (for user-friendliness perhaps?) but it is possible that these values not be hitting the sweet-spot of the sensor. A lot has been written about this subject online if you google.
The biggest difference between ISO 100 and 200 is not to reduce noise level using ISO 100 but to reduce shutter speed (twice reduce sensor sensitivity). This is very useful photographing on a sunny day or using studio equipment. Visually it is difficult to notice noise difference between iso 100 and 200 but the amount of light coming to camera sensor is very noticeable.
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