Geez, David! Isn't there some other e-mail system that you can use other than Excite? Look at all the trash that comes along with your e-mail!
Len --- ----- Original Message ----- From: "David Weiss" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, January 26, 2002 10:43 AM Subject: Re: Start-up B/W kit > Mike Johnston said:<br /> <br /> <br /> <br /> It certainly agrees with > my anecdotal evidence. I once brought home from the store five brand-new > lenses--an El-Nikkor 50/2.8, a Schneider Apo-Componon-S 45mm, a > Componon-S 50/2.8, a Rodagon 50/2.8, and an Apo-Rodagon-N 50/2.8--and > tested them all directly against each other. The Apo-Rodagon-N was the > clear winner, and the Schneider 45mm was so decentered that it was > obvious it was flawed even without careful testing. It was the second > sample I'd used of that lens and both samples were, in Ctein's terms, > "real dogs." <br /> <br /> <br /> <br /> Mike,<br /> <br /> <br /> <br /> > Can you tell me how you could tell the Schneider was decentered? Are you > saying the lens elements were not aligned and not that the lens was not > aligned with the rest of the enlarger? <br /> <br /> <br /> <br /> Any > other tips on how to check an englarging lens?<br /> <br /> <br /> <br /> > thanks<br /> <br /> <br /> <br /> dave (the lurker)<br /> <br /> <br /> > <br /> <br /> <br /> <br /> <br /> Schneider has since replaced that lens > altogether. <br /> <br /> <br /> <br /> I'm a real fan of the > Apo-Rodagon-N's, although the 105mm I tested was not <br /> <br /> any > particular standout. I only sold my Apo-Rodagon-N 50/2.8 when I replaced > <br /> <br /> it with the Carl Zeiss S-Orthoplanar 60/4, a lens which was > about eight <br /> <br /> times more expensive when it was new. <br /> > <br /> <br /> <br /> <br /> <br /> > The other thing is that some lenses > perform better, and are designed for <br /> <br /> > optimum performance, > at certain magnifications or distance from the <br /> <br /> > baseboard. > So you might want to compare the lenses with that in mind. <br /> <br /> > > You might find one works best for smaller prints and the other for <br > /> <br /> > larger prints. <br /> <br /> <br /> <br /> The big problem > here is that most darkroom workers--certainly beginners--are <br /> <br > /> not capable of employing enlarging technique good enough to see the > <br /> <br /> differences. Hell, most darkroom workers stop their > enlarging lenses way <br /> <br /> down, well past the optimum f-stop, so > the grain is mush anyway. I'm sure <br /> <br /> you've done this, Shel, > but for the benefit of others: if you take a very <br /> <br /> good > grain focuser like the Omega/Peak #1 and simply look at the film grain > <br /> <br /> as you stop the enlarging lens down, there's usually a very > obvious optimum <br /> <br /> f-stop--starting at wide open in the center > of the projected image the grain <br /> <br /> might go from indisctinct > to crisp to very crisp to less crisp to mushy to <br /> <br /> very mushy > as you stop down. <br /> <br /> <br /> <br /> Diffraction is a MUCH > bigger problem in the enlarging system than in camera <br /> <br /> > lenses. The only reason to buy "apo" enlarging lenses is that they are > <br /> <br /> diffraction-limited half a stop or a full stop wider open. > Any lens that <br /> <br /> allows you to print wider open will be > better--Ctein and Arthur Kramer, the <br /> <br /> lens guru from _Modern > Photography_ who started all this lens-testing <br /> <br /> business way > back when, used to have a running argument about which was <br /> <br /> > better--Arthur's Apo-El-Nikkor 105mm, which was diffraction limited wide > <br /> <br /> open at f/5.6, or Ctein's garden-variety but tested and > hand-picked <br /> <br /> Rodagons, which were diffraction-llimited at > f/4.5. Arthur actually won that <br /> <br /> argument when Ctein finally > got to test an Apo-El . But Ctein had a good <br /> <br /> point. <br /> > <br /> <br /> <br /> My S-Orthoplanar is diffraction limited wide open. > It beats the <br /> <br /> Apo-Rodagon-N by half a stop. Awesome lens. > <br /> <br /> <br /> <br /> - -- Mike <br /> <br /> <br /> <br /> "Ain't > photography grand. The more you know the less you know." (Shel <br /> <br > /> Belinkoff) <br /> <br /> <br /> <br /> * * * <br /> <br /> Find out > about Mike Johnston's unique photography newsletter, "The 37th <br /> <br > /> Frame," at http://www.37thframe.com<br /> <br /> <br /> <br /> > > -------------------------------------------------------------- ---------- > > <br /> > > <br /> <br /> > > -------------------------------------------------------------- ---------- > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
