Google| Subject | Re: ISO value names are becoming ridiculous |
| From | Whisky-dave |
| Date | 01/06/2016 18:11 (01/06/2016 09:11) |
| Message-ID | <7377ee44-0525-4ed2-a362-5169e49aa8a5@googlegroups.com> |
| Client | |
| Newsgroups | rec.photo.digital |
| Follows | Sandman |
| Followups | nospam (12m) Peter Irwin (52m) > Whisky-dave Sandman (5h & 30m) > Whisky-dave |
On Wednesday, 6 January 2016 15:11:08 UTC, Sandman wrote:
Sandmanwhich might not be a bitmap image BMP. It'sz got nothing to do with sensor amplification eithert.
In article <f97cb4e5-840a-47c7-ab91-1e7853f6650c@googlegroups.com>, Whisky- dave wrote:SandmanWhisky-daveSandmanSo 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 ?
The base would be what is today called ISO 100, which corresponds to an expected brightness level of the resulting bitmap image.
Why limit it to bitmaps?
Because ISO is film sensitivity and sensor amplification, so it's only a variable for the resulting image.
yes so, my point was that most cameras you normally set to fixed common ISOs 100, 200, 400, but with DIN the was more choices as thre were with film. you said 50 and 100 like you have to use either of those are you forgetting 64 and 80 ? DIN 19 and 20SandmanSo ISO 50 is one step lower than that, naturally.Whisky-dave
not a 'step' but half I'd say.
No, going from ISO 50 to ISO 100 is one full stop. The scale is arithmetic, remember. Each stop is a doubling of the value. ISO 100 is one stop more sensitive than ISO 50, just as ISO 800 is one stop more sensitive than ISO 400.
so why change it, but if you must chose a abetter system not a worse and confusing one by redefining what ISO is.SandmanWhisky-daveWhisky-daveSandman
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.
Which people understand when you talk about ISO 200 or ISO 6400 because those numbers are easier to understand.
I don;t remmeber having problems when I was exposing film at 10 ASA up to 6400 ASA
Which is what I just said...
So in your new world would 15 ISO be a fast or slow 'speed'
but it's not if you just use whats called teh significant bits/number like you have above why is 4 million ISO so complex it's twice as fast as 2 million and half the speed of 8 million ISO or 8M just like we do with semsor sizes and hard disc sizes.Whisky-daveSandman
I doubt I'd have any trouble working out what 12,800
Which is why it's only a problem now when we have ISO values of 3,200,000 and 4,000,000
On my MAc here it came with a 1TB drive well that;s what it's called but it's capacity is only 999.86 GB but it doesntl; realyl matter does it no one says they have an iMac with a 999.86 GB drive.
So why change it then, no one really used APEX because there was no reason to.Whisky-daveSandman
would have meant either. which is why DIN or EV would be better than ISO as sensitivities increase as they do today.
Which incidentally, is what I'm saying. In fact, the old arithmetic ASA standard had a logarithmic equivalent later called APEX which is very similar to what I am proposing, where APEX 5° = ASA 100 and APEX 6° = ASA 200 etc etc.
Only difference is that APEX 0° was equal to ISO 3, which no one used (or uses), so to reset the scale for ISO 100 seems more obvious today.why, it's not realy relivent to most users today.
Not quite as focusign systems and metering sensitivity can be expressed in EV. So you can have a meter which can measure down to EV 0 and it doesn;t mater what lens or shutter speed you elect to get to that level.SandmanWhisky-daveSandmanAnd 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.
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.
EV is for sensitivity really as it was the measure of the light level inside the camera not of the subject brightness.
??? EV stands for exposure value. It's the combination of shutter speed and aperture and that's it.
So any given exposure has an exposure value. Using ISO, you can then amplify the signal by one or more stops to emulate a different EV.That's no use though is it as the EV is fixed that's the point. It represents brightness as seen from the sensor or film plane, that's why it's useful.
So, shoot an image with 1/250 shutter speed at f4. That results in a bitmap with a given brightness. Now, change the ISO to 200 and that result would be amplified to be an equivalent EV as if you had used 1/250 f4 or 1/250 f2.So that doesnt; change the amount of light on the sensor does it, so the lighting level is the same that's why you get the same brighteness.
01/06/2016-
