On Friday, September 28, 2001 at 9:15, C.H.Ling <olympus@xxxxxxxxxxxxxxx>
wrote on "Re: [OM] [OT] Sensia II vs. Provia.," saying..
> After thinking again, I think both 8 stops and 10 stops are wrong.
> 1000:1 should be equal to around 5 stops only. Since contrast ratio is
> linear ratio and EV or stop value is energy, which follows square law.
No, each stop is a doubling & 2**10 is 1024, so 10 stops for 1024:1
> As you can see the contrast range that slide can capture is around 7
> stops. In general practice the normal black point is -2.5EV from grey
> and white point is +2.5EV from grey. That means the white to black
> different is 5EV that is most likely people using to test film (and
> lens) resolution, as normally their target is black strip on white
> paper.
>
> Also, 1000:1 is equal to D-range 3.0. which is definitely not enough
> for slides. If 1000:1 is equal to 10 stops, we will have no problem on
> using such scanner for our critical works.
>
> Again, LCD monitors has common contrast ratio of 1:350-500, which
> still need improvement, obviously they think it is not enough to
> compare with CRT. At the mean time you can see the Gas Plasma display
> has 1:3000 contrast ratio which is using in Hi-end TV display. Do you
> need a display to handle over 10 stops contrast different? No, I think
> they are just close to the slide's quality and D-range of around 3.5
> (between 5-6 stops).
Density is log10 of comparative opacity, so 3.0 = 1000:1 and
4.0=10,000:1 and D 3.5 = 3,162:1
--------------- Abacurial Information Management Consultants
Tom A. Trottier, President ICQ:57647974 http://abacurial.com
415-400 Slater St. Ottawa ON Canada K1R 7S7
+1 613 291-1168 fax:594-5412 N45.417 W75.705
(after 2001 Oct 20) 758 Albert St, Ottawa ON Canada K1R 7V8
+1 613 860-6633 fax:231-6115 N45.412 W75.714
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." -- Benjamin Franklin
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|