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Why do Oly reccomend against using ISO 100?

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don_van_vliet

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In the manual for the E-PL1 it suggests that ISO-100 should be avoided, unless low noise is a priority. Reading around it has been suggested that this is because the dynamic range may be compromised at ISO-100 as compared to ISO-200. However, when I checked DxOMark it suggested that the dynamic range was slightly higher at ISO-100 than at 200?! This would contradict Oly's advice.

Can anyone shed any light on this?
 
All I've read about this theme up to now is that the original sensor sensitivity is ISO 200. Any other ISO value comes by signal amplification or reduction what will not improve S/N ratio. Maybe measurement from DxO is not 100% representative. Anyway many user say ISO 200 has the best dynamic range in practical use.

Usillas
 
don_van_vliet said:
In the manual for the E-PL1 it suggests that ISO-100 should be avoided, unless low noise is a priority. Reading around it has been suggested that this is because the dynamic range may be compromised at ISO-100 as compared to ISO-200. However, when I checked DxOMark it suggested that the dynamic range was slightly higher at ISO-100 than at 200?! This would contradict Oly's advice.

Can anyone shed any light on this?
Click to expand...
If you have the camera, you just need to go shooting with it at ISO 100 and you'll see in many instances highlights start getting clipped sooner at ISO 100 than they are at ISO 200. That does not mean it cannot be used at ISO 100 and get great results. You just have to be more careful in exposing some scenes and, if clipped areas are a real problem for you, be prepared to shoot RAW so you can get at least some of it back in processing the files later.

With many of the micro-specific lenses being slow zooms, ISO 100 can also lead to slower shutter speeds and less the optimum sharp images in lower light if you are not using some form of support. Stabilization is good to a point, but I do not think it is as good as advertized.
 
don_van_vliet said:
In the manual for the E-PL1 it suggests that ISO-100 should be avoided, unless low noise is a priority. Reading around it has been suggested that this is because the dynamic range may be compromised at ISO-100 as compared to ISO-200. However, when I checked DxOMark it suggested that the dynamic range was slightly higher at ISO-100 than at 200?! This would contradict Oly's advice.

Can anyone shed any light on this?
Click to expand...
--When I saw that, I wasn't sure why.
W.C.

http://www.flickr.com/photos/29320396@N05/show/
 
don_van_vliet said:
However, when I checked DxOMark it suggested that the dynamic range was slightly higher at ISO-100 than at 200?! This would contradict Oly's advice.
Click to expand...
Check again!

Hover your mouse on the spot and you'll see a hint saying the ~10.1EV you think you see at ISO 100 (it's really a measured ISO of ~130 and a manufacturer declared ISO 200), so nothing wrong with that. DXO Mark doesn't measure ISO100 on the Olympus.
But if you check the first graph of all (ISO Sensitivity) it's all pretty clear.
--
Duarte Bruno
 
don_van_vliet said:
In the manual for the E-PL1 it suggests that ISO-100 should be avoided, unless low noise is a priority. Reading around it has been suggested that this is because the dynamic range may be compromised at ISO-100 as compared to ISO-200.
Click to expand...
Not may be, will be. ISO 100 is just an over exposed ISO 200 shot on this camera.
don_van_vliet said:
However, when I checked DxOMark it suggested that the dynamic range was slightly higher at ISO-100 than at 200?! This would contradict Oly's advice.

Can anyone shed any light on this?
Click to expand...
No, you just need to look at the graph more carefully - it is a bit confusing. They don't measure the ISO 100 point for DR or SNR since it isn't a different RAW setting. The last points measured are ISO 200 (mouse over the point to see the ISO setting). Their graph is for measured ISO, which is why you were confused into thinking they had measured ISO 100.

As someone else suggested also look at the ISO sensitivity graph and you can see ISO 100 and ISO 200 have the exact same response.

From a RAW shooting perspective ISO 100 is no different than shooting ISO 200 with +1 eV. From a JPEG perspective of course things could be different...

The basic trade off is your mid-tones and some shadows will have less noise at the ISO 100 setting but you'll have less highlight headroom (just like over exposing at any setting would).
--
Ken W
See plan in profile for equipment list
 
Usillas said:
Maybe this helps:
http://www.dpreview.com/reviews/olympusep1/page20.asp
Click to expand...
This has been the case with every Olympus camera, DSLR or mirrorless, going back 2-3 generations of consumer bodies. No need for anyone to question it. All you have to do is take pictures to see it. If you use ISO 100, you pay a price in less dynamic range. Just because Olympus has not published an official comment about it does not mean it is not so, but I do not think they could have made it any clearer in completely dropping any ISO 100 option in the E-PL2.
 
Iliah Borg said:
Iliah Borg said:
All you have to do is take pictures to see it.
Click to expand...
Taking pictures does not allow to see what dynamic range is. To determine dynamic range one needs at least to process those shots. And here is a surprise. Believe it or not, processing affects dynamic range.
Click to expand...
Then I guess them removing ISO 100 all together in the E-PL2, which uses the same sensor as the previous models, goes a lot further in showing ISO 100 was simply an extension?

Yes, if you take care to not overexpose at all and flatten the tone curve completely you can cover about as much dynamic range as you want with any camera. How much you like the resulting images is another thing.
 
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