Expandable ISO

jryans10

jryans10

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Hi all,

So I now use a Nikon D300 and it goes down to 200 ISO when I would've thought it would've gone down to 100. However, it does have a LO 1 setting which I believe is 100 ISO.

Now, is there anything wrong with using LO 1? Also why would they have done this as a LO setting rather than just 100?

Talking about ISO, if the D300 can go up to let's say 6,400 if I'm not mistaken, why don't they just put "6400" instead of "HI 1"?

A bit confused ^^.

Thanks all.
John.
 
Last edited:
jryans10 said:
Hi all,

So I now use a Nikon D300 and it goes down to 200 ISO when I would've thought it would've gone down to 100. However, it does have a LO 1 setting which I believe is 100 ISO.

Now, is there anything wrong with using LO 1? Also why would they have done this as a LO setting rather than just 100?

Talking about ISO, if the D300 can go up to let's say 6,400 if I'm not mistaken, why don't they just put "6400" instead of "HI 1"?

A bit confused ^^.

Thanks all.
John.
Click to expand...

As far as I know it's because the H1 etc is not a real ISO rating but is achieved by under exposing the shot and then pulling it up in the in-camera processing.

.
 
The iso range is a compromise between dynamic range and noise. Using the hi and lo settings has quite a dramatic effect on the dynamic range that the sensor can record.
 
petersmart said:
As far as I know it's because the H1 etc is not a real ISO rating but is achieved by under exposing the shot and then pulling it up in the in-camera processing.

.
Click to expand...

That makes sense... but... err.. simplistically; CCD is a bit of silicon; that for want of better description, counts photons, and delivers proportional number of electrons, which camera counts to decide how bright a pixie should be.

SO.... the ISO setting on the camera, is in essence, the 'exchange rate'... how-many photon's you need to catch to get whatever pixel brightness value....

Electrically, the ISO setting is setting the out-put amplification from the CCD, and the camera is shifting its sample thresholds for pixel brightness values, within CCD out-put range.....

So, if the marked ISO settings are electrically CCD amplified sensitivities; pre-sampling, and Hi- or Lo settings are merely sampling threshold-shifts... what's the practical difference?
 
At a guess, the manufacturers aren't happy enough with the quality from the Hi and Lo extended ranges so mark them as Hi and Lo rather than the (probably a bit approximate) ISO sensitivities. The extended settings might not even reach ISO standards (but that's pure conjecture on my part!)
 
Bristolian said:
The iso range is a compromise between dynamic range and noise. Using the hi and lo settings has quite a dramatic effect on the dynamic range that the sensor can record.
Click to expand...

Thanks everyone for your help.
So am I right in saying that even when it's really bright, I should use ISO 200 and not LO 1?

Thanks!
John.
 
jryans10 said:
Thanks everyone for your help.
So am I right in saying that even when it's really bright, I should use ISO 200 and not LO 1?

Thanks!
John.
Click to expand...

Exposure Triangle.....

Shutter-Speed vs Aperture vs ISO

What's most important?
- Freezing or blurring movement / Avoiding camera shake?
- Controlling Depth of focus?
- Possible Noise?

Its all circumstance dependent. One stop of IS is the same as one f-stop of aperture or Shutter Speed.

So if it's really bright; you can either go up an F-Number on aperture or halve the shutter speed and get the same exposure at ISO200 as you would ISO100;

Only be an issue if you wanted wide aperture for shallow Depth of Focus, and didn't have a higher shutter speed to go up to; or if you wanted to use longer shutter speed to blur motion, and were already stopped down to highest f-number.....

Of course, better to have too much light than too little! Can always stick a Neutral Density filter in front to dim it down... tends to be rather easier than trying to light up a Stadium with a flash-gun!

But, setting is there; no reason why you shouldn't use it, if appropriate, unlikely that mere mortals will be able to tell much difference between pseudo ISO setting and a real one!
 
Using the Hi and Lo settings applies exposure adjustment post the analogue/digital conversion, effectively the same as pushing or pulling exposure in post processing.

Basically the effect is a loss of dynamic range. With the Lo setting you'll lose one stop of highlights headroom, and with Hi there will no improvement in shadow detail.
 
HoppyUK said:
Using the Hi and Lo settings applies exposure adjustment post the analogue/digital conversion, effectively the same as pushing or pulling exposure in post processing.

Basically the effect is a loss of dynamic range. With the Lo setting you'll lose one stop of highlights headroom, and with Hi there will no improvement in shadow detail.
Click to expand...

Do Nikon & Canon do it the same way Richard ?
 
Nod said:
The extended settings might not even reach ISO standards (but that's pure conjecture on my part!)
Click to expand...

This could be one of the reasons, I know you're right about it on the 6D anyway
 
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