Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site peora.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!petsd!peora!jer From: jer@peora.UUCP (J. Eric Roskos) Newsgroups: net.rec.photo Subject: Re: Yashica Mat 124-G Message-ID: <1065@peora.UUCP> Date: Thu, 13-Jun-85 13:19:48 EDT Article-I.D.: peora.1065 Posted: Thu Jun 13 13:19:48 1985 Date-Received: Sat, 15-Jun-85 06:08:24 EDT References: <981@peora.UUCP> <2720038@acf4.UUCP> Organization: Perkin-Elmer SDC, Orlando, Fl. Lines: 59 > In principle, the 6x6 should offer more resolution than 35mm, but at least > for color work, the sharpest films available are only made in 35mm (read > Kodachrome 25). This probably has at least twice the resolution of > Ektachrome 100. The 2 stop speed loss is compensated by the considerably > faster optics of the 35mm format (f1.4 vs. f2.8). Let's have some hard figures here! Every week there are 2 or 3 testamonials from the Kodachrome 25 worshippers, who indignantly inform us heathens who make photographs on strange brown films that there is nothing better. (I even recall one contributor who cited the prophet Simon, who wisely observed that "Kodachrome...brings out the night's bright colors." This would not be too surprising to me, since my data sheet "Reciprocity Data for Kodak Films" indicates that Kodachrome should not be used for nighttime photography.) [While we're on the subject, though... the only film that Kodak DOES recommend for nighttime photography is not available in 35mm.] This makes it hard for me to distinguish Kodachrome 25 from other mysterious objects with "good" properties, such as BMWs. Now, I've seen the comparative photographs published by Kodak that indeed show that the Kodachrome resolution is not that bad. Personally, if I was going to use a color reversal film, I would probably use Kodachrome. But, they have ways of rating these films, some of them even specified by the ANSI. So... does anyone have the data sheets for Kodak color films? (I don't -- Kodak has been "out of stock" on them ever since I first became seriously interested in getting to the bottom of all this several months ago.) If you do have the data sheets, and want to contribute to getting some reasonable comparative facts together, mail to me the following information on the films you have data on: the resolution and the RMS granularity, D-min, the lux-seconds and density at which the characteristic curve becomes linear for each of the three color emulsions, and the approximate lux- seconds value at which the density reaches D-min.* I hope I won't get an unmanageable flood of mail, but I am curious about the properties of these alleged color films. Not just slide films; color negative films, including in particular VPS and VPL. (I wish I could get some comparative data on "color rendition," but alas, I don't know how to do that at present. Any suggestions?) ---------- *I'm referring here to the "toe" length; most negative films don't start to flatten out at the other end within the usable range: only slide films have that problem. PS - my apologies to the many people who have perfectly rational reasons for using Kodachrome 25. I just get annoyed when I see only inexact or irrational ones. -- Full-Name: J. Eric Roskos UUCP: ..!{decvax,ucbvax,ihnp4}!vax135!petsd!peora!jer US Mail: MS 795; Perkin-Elmer SDC; 2486 Sand Lake Road, Orlando, FL 32809-7642 "Gnyx gb gur fhayvtug, pnyyre..."