At which point, looking around and deciding 1/30 at f8, click, is about as safe.
E. On Mar 19, 2007, at 9:01 PM, Richard Knoppow wrote:
----- Original Message ----- From: "Robert Lilley" <54moggie@xxxxxxxxxxxxx>To: <rollei_list@xxxxxxxxxxxxx> Sent: Monday, March 19, 2007 4:04 PM Subject: [rollei_list] Re: An ebay explanationRichard, et al, I took a reading from the same area with both my Gossen Luna Pro F and Weston Master II. Making sure I didn't move the arrow, I set the Weston to reflect the same speed to f/stop settings the Luna Pro exhibited using the film speed slide. This gave me a Weston speed reading half way between 100 and 125 so I called it 112 which turns out to be 56 percent of the ISO speed of 200. Not far from your 40 percent you stated earlier today. I agree with all who state that technique is important when using such a wide acceptance meter like the Weston. I find myself taking the darkest reading and the lightest I can find in the scene and averaging between the two. I think I read somewhere that AA figured out what became the zone system using a Weston. Of course I can just forgo all this with the Weston and stick to the Luna Pro. The Luna Pro has the Zone System scale set up to work with the arrived at EV - but its fun to use old stuff and make it work out and besides, the Luna Pro F is the size of a house and takes a battery that would start my car* - and I thought a Weston meter was big. One has to admit the Weston meters were built to last. Rob *literary licenseAnd just what is your literary license number?I did the same test a couple of hours ago and got the same result I also used a Luna-Pro as the standard and used a blank print mount forthe reflecting surface. It was a bright overcast, I think we have rain coming. In any case, the speed setting for the Weston for the same exposure as the Luna-Pro was 64 for ISO-100. This is not exact as the speeds on the Weston are different. The Luna-Pro for instance has 1/125th and the Weston 1/130th. I think these are close enough. Again, the old charts show that Weston speeds should be about 80% of ASA speeds, or the next lowest Weston number to the ASA number. However, the old ASA system had a one stop fudge factor which the ISO system does not. Its possible the old conversion charts took this into account. That would explain why using the next-lower-number conversion results in underexposure. Weston may have been correcting for the blunder made by the ASA in adding this fudge factor to the speeds. The curious thing is that the ASA method was adopted from a method developed at Kodak mostly by Loyd A. Jones. Its intention was to find the _lowest_ exposure that would result in good tone rendition on the basis that thinner negatives tend to be finer grained and sharper than dense ones.The ASA, or whoever, blew this out the window by halving the speeds. Thefudge factor was dropped when the ASA adopted a variation of the "new" DIN method about 1958. --- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org- Online, searchable archives are available at //www.freelists.org/archives/rollei_list
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