File :-(, x, )
Anonymous
>> Anonymous
lol
>> Anonymous
Anyone care to explain why Nikon has renamed ISO 100 to 'Lo 1' and ISO 6400 to 'Hi'?
>> Anonymous
I like the sound of this wireless stuff though.
>> Anonymous
Canon > Nikon

The eternal law of science and all that is good.
>> Anonymous
>>72673
ISO 200 is the optimal light gathering point on the D300 (to maximize signal to noise ratio). In fact the "LO 1" mode on the D300 is actually emulated using a modified ISO 200 signal from the sensor.

Likewise, ISO 6400 is not a real sensor sensitivity on the D300, it's also emulated. (Hence why they call it "ISO 6400 with boost")

This is probably why the naming is Lo 1 and Hi 1 - they're not real ISO values, but faked.
>> nokin !ozOtJW9BFA
>>72682
Why do you feel the need to do this? this is a question about the nikon camera firmware. not a canon vs nikon debate.
>> Anonymous
>>72754
>ISO 200 is the optimal light gathering point on the D300 (to maximize signal to noise ratio).

Could you explain thus more?

And could you also explain what, if any, negatives there are to the "faking?"
>> Anonymous
>>72778
Sure.

First of all, see Wikipedia excerpt from article "Film speed" - "Film speed is found by referencing the Hurter–Driffield curve, or D–logE curve, for the film. This is a plot of optical density vs. log of exposure (lux-s). There are typically five regions in the curve: the base + fog, the toe, the linear region, the shoulder, and the overexposed region. Following the curve to the point where density exceeds the base + fog by 0.1, find the corresponding exposure. Dividing 0.8 by that exposure yields the linear ISO speed rating."

In layman's terms, this is a fancy guideline for figuring out at which exposure a very small difference in light (0.1) can be measured.

Nikon's guideline is to set the default ISO (sensitivity) to the one that gives the best measurement in terms of signal to noise. For the D300, Nikon's experiments probably showed that the best signal-to-noise ratio happened at ISO 200 sensitivity. They set this as default and rename ISO 100 to "LO 1" to reduce the confusion from people who do not understand how it works and assume that ISO 100 will always give them the smoothest possible picture from the camera.

Unfortunately it also turns away people who assume that it's inability to do ISO 100 is a flaw. It's a tough thing to explain this kind of stuff to most consumers, it's like trying to explain how Intel's new 2.8 Ghz processor is better than their older generation 3.0 Ghz processor.

Then there's other people who think it's awesome because you're getting the best possible performance out of the camera at higher ISOs. Also a fallacy.

So keep in mind, it's neither a flaw nor a feature yet. We'll only know for sure after we see good samples from the D300.

As far as Lo 1 and Hi 1: They get these by modifying the signal AFTER exposure. The disadvantage is that a Lo 1 (ISO 100) picture is not going to be any smoother than an ISO 200 picture on the D300 (it may even be slightly degraded in comparison).
>> Anonymous
But why would a higher ISO have less noise? That was my question.
>> ac !!VPzQAxYPAMA
>>72875
Disclaimer: This theory is pulled out of my ass.

Noise is more likely to appear in longer exposures, because noise is a semirandom occurrance and is effected by things like temperature. More time means a hotter sensor and more time for random noise to creep in. That's why cameras have to do long-ass dark-frame-subtraction noise reduction on long exposure shots, even at low ISO.

So it might be that ISO100 and ISO200 have naturally equal noise characteristics but the fact that ISO100 doubles your time needed to get the same exposure time, it ends up being noisier.
>> Anonymous
>>72875
Sure. Higher sensitivities can lead to higher noise.

But that's not what they're measuring. They're measuring the signal-to-noise RATIO, and apparently that ratio is higher for ISO 200 than it is for ISO 100 on the D300.
>> des
The ISO equivalent in software is just changing the gain on sensor.

Think of it like an old diesel genny
She's got an idle speed that she likes to sit at, it's the point where she provides the most electricity the quietist.
You need moar? So you rev her up and she gets all pissed off and hon'ry. You got the extra juice you wanted but it's making more noise.
You need less? Resistors all burnt out and you're worried about surges? So you take her under her favourite idle and she starts a-chugging. You've got less juice but it's just a tad rougher going.

...and that, my friends, is the only time you'll ever see an imaging sensor->generator analogy.
>> Anonymous
>>72875
Higher ISO is correlated with higher noise. But it's not a cause-effect relationship. There are many factors that contribute to noise, and ideally, we'd all have cameras that can take low noise pictures at very high ISO. Check out the Canon EOS 1-Ds Mark III. Expensive as hell but it takes pictures at 6400 ISO that are unbelievably smooth.
>> ac !!VPzQAxYPAMA
>>72907
Your rustic patois in this post was exquisite.
>> Anonymous
txt
>> Anonymous
>>72917
what
>> des
>>72910
had to look that up, damn city folk ;P