D90 and ISO 100

[gogu]

<p>Hi all!<br />I have a question regarding the Lo 1.0 setting on my D90.<br />If I want to use my camera permanently at ISO 100 (Lo 1.0), do I lose something in IQ?<br />I mean, is this setting going to produce more noise for instance, CA or other kind of image quality degradation/deterioration of my pictures, than when I use the camera set at its standard lower ISO which is ISO 200?</p>

<p>Thanks!</p>

[Peter_in_PA]

<p>ISO 200 is the base setting. You gain nothing by going lower except longer shutter speeds. From everything I've seen, DSLRs behave best at the base ISO settings. Leave it at 200.</p>

[joe_a2]

<p>Good Morning Gogu.... Lo 1.0 is going to be WORSE than the base ISO setting on any camera. The dynamic range of the sensor gets smaller, i.e. the range of light-to-dark that the sensor can capture is reduced.</p>

<p>If you want to shoot at "ISO 100", put a 1-stop Neutral Density filter on the lens and shoot at ISO 200. If you need "ISO 50", put a 2-stop ND filter on your lens and shoot at ISO 200. Simple!</p>

[richard_driscoll]

<p>I agree with Peter and Joe. The main effect of running below base ISO is to reduce dynamic range. The explanation is roughly as follows.<br /> <br /> With a picture correctly exposed at base ISO the brightest parts of the scene will take the sensor to about saturation (the point at which an increase in brightest produces no more output). When you increase the ISO, some amplification is inserted between the sensor and the A to D converter. This is fine except that the dark parts of the picture tend to disappear into the noise.<br /> <br /> However when you decrease the ISO below the base the signal is reduced, probably prior to the A to D converter, though it could be after it. The bright parts of the picture can now exceed the level at which the sensor saturates implying a loss of dynamic range.<br /> <br /> Some people claim that a low base ISO is an advantage but in general this is not so. It just means more susceptability to camera shake, less DOF etc. and as Joe points out you can get the same effect with an ND filter!</p>

[Sanford]

<p>My D80 has a base ISO of 100 but I always use ISO 200 as a base just to stay consistent with my D50 and D300 which start at ISO 200. I shoot a lot of manual exposure and don't want to have to remember which camera I'm using. I think the D80 looks just as good or better at ISO 200 that it does at it's base ISO.</p>

[munim]

D90 ISO 100 is actually ISO 200. And most DSLRs have the actual ISO below the selected ISO.

 

Go to:

http://www.dxomark.com/index.php/eng/Image-Quality-Database/Nikon/D90

Then click on the "ISO sensitivity" tab.

 

I'm not sure if setting the ISO to Lo.1 will be worse than base 200, but I agree with Joe: use an ND filter to go lower than

base ISO.

[rossb]

<p>ISO 100 is pretty much history now with the major DSLR brands. The Mamiya 645 with digital back offers ISO 50. A landscape shooters dream.</p>

[richard_driscoll]

<p>Raden,<br>

Your observation seems to be true mainly for the Nikon cameras with 12 MP DX sensor (D300, D90 and D5000). The D40 , D80 and D3 ISOs all seem to be pretty nearly correct and their sensors are all different<br>

The D90 seems to have the same measured ISO at 100 and 200!!! I wonder how ISO 12232 defines sensitivity?</p>

 

[ramon_v__california_]

<p>gogu, you must be a film/slide guy. with digital sensors it is not how we used to do it in the film/slide days. the use of filters, as mentioned above, has also served me well and answered my desire for lower iso.</p>

[rossb]

<p>I do like the web site that Raden has shown us. Not only ISO sensitivity but also Dynamic range. I have seen no charts on dynamic range and am suprised in the significant reduction in dynamic range as you increase ISO. Pretty neat. That chart is marked as a keeper. Thanks Raden.</p>

[bsd230]

<p>I love the DXOMark website. It really gives you an idea of image quality of every camera on the market.<br>

As far as ISO 100, as others have said you would be better off shooting at ISO 200. You can nothing by shooting at ISO 100 in terms of image quality. It doesn't seem like it would be that way, but with Nikon they work best at ISO 200. I am used to shooting at ISO 100 as well, but with the image quality possible at ISO 200 I don't mind the switch. My current camera is the first that I actually leave in auto ISO mode most of the time and it works great.</p>

[gogu]

<p>Thank you all for your answers!<br>

So ISO is going to stay at 200, nothing to gain shooting at Lo 1.0!<br>

@ Raden: thank's a lot for the link, that site is invaluable!<br>

@ Ramon V: yup, I'm a film guy, the D90 is my first DSLSR (see my profile;-)).</p>

[richard_driscoll]

<p>It turns out that the ISO sensitivity measurement that DXO use is related to the saturation sensitivity. As I pointed out above that is unchanged by a shift from ISO 200 to ISO 100 and that is why the measurements for ISO 100 and ISO 200 are the same. It essentially confirms that the dynamic range will be reduced if you expose at a level appropriate for ISO 100.</p>

<p> </p>

[munim]

You're all welcome anytime! ;)

 

@gogu: I'm like you too. D90 is my first DSLR.