Sandman
In article <f0f8cc67-6eee-4d36-a899-6fc3c40bcfe1@googlegroups.com>, Whisky-dave wrote:

So with the D5, it can boost its ISO to ISO 3,280,000, and suddenly how ISO is named is becoming just stupid. We should use EV steps instead:

Whisky-dave
SO why start at -1 ?

Sandman
The base would be what is today called ISO 100, which corresponds to an expected brightness level of the resulting bitmap image.

So ISO 50 is one step lower than that, naturally.

That would put more normal values to these numbers. The Hi5 setting of the D5 sounds unbelievably high, which of course it also is, but it's "only" twice as "sensitive" as ISO 12,800, but the way ISO is named makes it look stupid as fuck.

Whisky-dave
are you sure about that as it makes NO sense or is it nonsense. Doubling the ISO effectively doubles or makes it twice as sensitive to light meaing you only need half the exposure.

Sandman
Which people understand when you talk about ISO 200 or ISO 6400 because those numbers are easier to understand.

While few understand it's "only" five exposure stops between those values and they may seem like a larger difference than what they really are, the entire system falls apart when you compare ISO 102,400 with ISO 3,276,800, which is also a five stop difference.

And, when talking about ISO, you'd just say "it was shot at ISO 3" instead of ISO 800.

Whisky-dave
Might be better to not use the same term ISO.

Sandman
I considered that, but this is by now so entrenched that it's hard to change too much. SB+5 might work, SB for signal boost. :)

And the new D5 would have a max ISO value of "ISO EV+10" which can be pushed in-camera to "ISO EV+15", which would still be equally impressive.

Whisky-dave
EV values already have a meaning best not to change them.

Sandman
Yes, and ISO can be part of the EV. So when changing the EV by using the ISO setting, it would be "ISO EV+4" for instance. Meaning that with "ISO EV 0", ISO is no part of changing the EV.