I have some questions on this lens which arrived with this morning's post, which I'm hoping the cognoscenti on this forum can answer.
First, what I do know is, by looking at the Dallmeyer catalogue that the lens is a wide angle landscape no.4, which covers up to 12x10 inches, and has a focal length of 12 inches (approx 300mm);
Its serial number is 46546, which seems to date it to 1899/90.
The rotating stops have values of 30, 50, 75, 100 & 150. I have found a table which seems to provide the equivalent f/stop for these values;
Is this table correct? The Dallmeyer catalogue seems to suggest f/15 for the largest f/stop - ie a difference of about half a stop from the table.
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