Archived posting to the Leica Users Group, 2006/12/09
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]well - just like adding a tiny pinch of salt to your food. The quantity may be minuscule but it can make all the difference. "add just a pinch more light, then scan" any decent modern camera can easily add that extra 1/3 of light. Eric On 12/9/06, Walt Johnson <walt@waltjohnson.com> wrote: > > Steve > > Might better ask if meters and shutters are accurate enough to make a > difference. Don't know what kind of eye could readily spot 1/3 of a stop? > > Steve Barbour wrote: > > > > > On Dec 8, 2006, at 4:32 PM, Eric Korenman wrote: > > > >> TCN does best at ISO 320. > >> It gets way too thin at ISO 800. > >> just 2 cents from shooting hundreds of rolls of the stuff. > > > > > > > > btw, is the latitude of this film so narrow/sensitive that shooting > > at ISO 320 rather than 400 makes a visible difference? > > > > thanks, Steve > > > > > >> > >> Eric > >> > >> On 12/8/06, Walt Johnson <walt@waltjohnson.com> wrote: > >> > >>> > >>> Steve > >>> > >>> It sounds as if you're going to underexpose by a stop. What > result are > >>> you looking for? > >>> > >>> Walt > >>> > >>> Steve Barbour wrote: > >>> > >>> > Walt and others... have you shot C41bw 400, at 800 with normal > >>> > development? Results? > >>> > > >>> > I see this now as advantageous, have never done it, but I plan to > >>> > try.... > >>> > > >>> > thankjs, Steve > >>> > > >>> > > >>> > On Dec 8, 2006, at 6:41 AM, Walt Johnson wrote: > >>> > > >>> >> I think I'll start shooting all my Tri-X at 666 ISO. BTW > has anyone > >>> >> noticed the change (years ago) from ASA to ISO appears useless? > >>> >> > >>> >> Henning Wulff wrote: > >>> >> > >>> >>>> Doesn't it have something to do with logging rhythms. in .3 > >>> >>>> increments? > >>> >>>> > >>> >>>> Henning Wulff wrote: > >>> >>>> > >>> >>>>> At 10:29 PM +0100 12/6/06, Philippe Orlent wrote: > >>> >>>>> > >>> >>>>>> I was just remembering my ISO scale on the back of my MP: > >>> >>>>>> 50-100-200-400-800- etc. > >>> >>>>>> > >>> >>>>>> But the zones in between are divided in 3 parts. > >>> >>>>>> > >>> >>>>>> So between 50-100: 50/3=16,7 > >>> >>>>>> Between: 100-200: 100/3=33,33, which would put 160 at 100 > >>> and 2/3ds > >>> >>>>>> Two full stops under brings us at > >>> >>>>>> 400 and 2/3ds > >>> >>>>>> Which is 400 + (800-400)x2/3= 666,7 > >>> >>>>>> > >>> >>>>>> I may be wrong, but it looks like Leica logics to me. > >>> >>>>>> :-) > >>> >>>>>> Philippe > >>> >>>>>> > >>> >>>>> > >>> >>>>> ISO is not continuous. It's only defined for the discrete > >>> >>>>> progression (from 100 to 3200) for 100, 125, 160, 200, > 250, 320, > >>> >>>>> 400, 500, 640, 800, 1000, 1250, 1600, 2000, 2500, 3200. > >>> >>>>> > >>> >>>>> No numbers in between, ie, there is not 'ISO 300' or 'ISO 666'. > >>> >>>>> > >>> >>> > >>> >>> ISO combines the old ASA and DIN scales, and makes > the measurement > >>> >>> methods and ratings equivalent. DIN was logarithmic while ASA was > >>> >>> arithmetic, with 400 ASA = 27DIN, 320 ASA = 26 DIN. For > every step > >>> >>> the ASA took an arithmetic step, and DIN took a logarithmic step. > >>> >>> Different measurement methods meant that there wasn't a complete > >>> >>> equivalency, but then they got together and came out with the ISO > >>> >>> method and scaling, which allows for both an arithmetic and > >>> >>> logarithmic scale. So now the old 400 ASA is approximately > >>> ISO 400/27. > >>> >>> > >>> >>> Both systems jump in discrete, defined steps with intermediate > >>> >>> values undefined. > >>> >>> > >>> >> > >>> >> _______________________________________________ > >>> >> Leica Users Group. > >>> >> See http://leica-users.org/mailman/listinfo/lug for more > >>> information > >>> > > >>> > > >>> > > >>> > _______________________________________________ > >>> > Leica Users Group. > >>> > See http://leica-users.org/mailman/listinfo/lug for > more information > >>> > > >>> > >>> _______________________________________________ > >>> Leica Users Group. > >>> See http://leica-users.org/mailman/listinfo/lug for more information > >>> > >> > >> _______________________________________________ > >> Leica Users Group. > >> See http://leica-users.org/mailman/listinfo/lug for more information > > > > > > > > _______________________________________________ > > Leica Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more information > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >