LO1 ISO setting

[joe_cormier]

<p>My Nikon 300s has a LO1 ISO setting. I have never used it opting for the ISO 200. My question is what is the negative effects if any using this setting? I know Cannon has a standard ISO 100 setting. Is the Nikon LO1 comparable to the Cannon ISO 100?<br>

As always, thanks in advance. Joe</p>

[ShunCheung]

<p>Theoritically, if you go to a "low" setting below the base ISO, which is ISO 200 on the D300, D300S, D3, and D700, you may lose some details in the highlights, i.e. the bright areas. Therefore, typically I don't such such ISO settings. However, in the few times I have actually used that, I don't really see much difference from the base ISO.</p>

<p>More recent Nikon DSLRs such as the D7000, D800, etc. have a base ISO of 100 instead of 200.</p>

[daverhaas]

<p>The Low 1 is equal to an ISO 100 - but as Shun points out you may lose some detail. Exposure wise - 100 ISO is 100 ISO so if everything is equal and you are in Low 1 and a Canon is at 100 ISO - then both would give the same meter reading. There may be a difference in image quality because of the base ISOs - but that would be it. </p>

<p>Officially it is a "trick mode" like the High ISOs, but it works. </p>

<p>Personally I'd prefer that they kill the trick ISOs and just go with a straight range of 100 - 12800 or 25600... </p>

<p>Dave</p>

 

[eric_arnold]

<p>i never use it.</p>

[kari_oinonen]

<p>According to: <a href="http://home.comcast.net/%7ENikonD70/Charts/PDR.htm#D3S,D4" rel="nofollow" target="_blank">http://home.comcast.net/~NikonD70/Charts/PDR.htm#D3S,D4</a><br>

(Choose your camera model in the right side, several can be selected.)<br>

The dynamic range does not increase when you go to ISO 100 from the base 200. But the dynamic range does not drop either. <br>

With this info, in some cases, I am going to use Lo -values with my D700.</p>

[Andrew Garrard]

<p>I believe the D300s sensor has an analogue amplification stage which can produce outputs corresponding to ISO 200 to ISO 3200. Using the expanded (LO and HI) range, the camera deliberately over- or under-exposes (respectively), but tags a RAW file to indicate that the result should be "pulled" or "pushed" (or it performs the same operations internally to the camera for JPEGs) respectively.<br />

<br />

Therefore the "LO" settings should contain more shadow detail but less highlight detail than ISO 200: LO-1 contains the same information as an ISO 200 image shot with +1 exposure compensation, then pulled in post, so highlights will have clipped but the shadows are being recovered in more detail.<br />

<br />

The "HI" settings should contain more highlight detail but less shadow detail than ISO 3200 - HI-1 is equivalent to shooting at ISO 3200 but -1 exposure compensation, then correcting by a stop in post-processing, so there's extra highlight detail from the underexposed image but missing shadow information.<br />

<br />

With the proviso that the LO settings are more prone to highlight clipping than base ISO, and that the HI settings will have even more shadow noise than the highest "normal" ISO setting, there's nothing wrong with them. If you need ISO 100 or ISO 6400, it's not like there's another way to do it.<br />

<br />

If the RAW file actually contained numerically scaled values clipped to a "normal" range, data would be thrown away in the LO and HI settings, reducing dynamic range. However, I believe RAW formats tend to contain the sensor data as recorded and include a numerical scale factor that the RAW processor uses, so there shouldn't actually be an absolute loss of information outside the default range.<br />

<br />

Incidentally, I believe (from some magazine tests) that the D7000 <i>always</i> uses the same sensor analogue amplification and shifts everything digitally. Effectively, everything but base ISO is "HI" for that camera - but it's a testament to how much dynamic range the sensor captures. I assume Nikon chose to label the ISO settings as with their other cameras for consistency.<br />

<br />

I hope that helps explain what's going on.</p>

[kari_oinonen]

<p>Andrew, thank you for the added info I was hoping to get somewhere sometime.</p>

[Andrew Garrard]

<p>Glad to help - and I hope I've correctly interpreted why the dynamic range is showing up the same for LO and for base ISO!</p>