{"id":33026,"date":"2025-12-24T01:03:42","date_gmt":"2025-12-24T05:03:42","guid":{"rendered":"https:\/\/phsc.ca\/camera\/?p=33026"},"modified":"2025-12-22T03:09:09","modified_gmt":"2025-12-22T07:09:09","slug":"focussing-issue-resolved","status":"publish","type":"post","link":"https:\/\/phsc.ca\/camera\/focussing-issue-resolved\/","title":{"rendered":"focussing issue resolved …"},"content":{"rendered":"
\"\"<\/a>

a somewhat out of focus photo<\/p><\/div>\n

Toronto<\/strong>. Consistent with editor Lansdale’s inspiration to celebrate our 25th anniversary, the folks at the Cascade Panorama Historical Society sent in a juicy article by Milan Zahorcak titled, “What the …?”. Milan describes the problem raised when an old lens was tested and the novel solution.<\/p>\n

Milan’s story begins, “‘Actinism (Greek: a ray). A ray of light whether proceeding from a heavenly or terrestrial\u00a0<\/i>body is found, in general, to possess three properties; viz., the luminous, the calorific and the\u00a0<\/i>actinic. The actinic is that property of the ray which produces important changes in certain sub<\/i>stances submitted to its action, and on the use of which the whole art of photography is found<\/i>ed. When a ray of light is decomposed by refraction through a prism into its constituent colours,\u00a0<\/i>it is found that actinism exists chiefly among the violet, and scarcely at all among the yellow\u00a0<\/i>and red rays. Hence the importance of combining the violet or actinic focus of a photographic\u00a0<\/i>lens with the yellow or luminous focus: for the actinic rays produce the photographic picture,\u00a0<\/i>while, the luminous rays render the image visible upon the focussing screen.’<\/i><\/p>\n

“Follow all that? It’s straight from A Dictionary of Photography<\/i>, by Sutton &\u00a0Dawson, 1867, and it’s been a 140 years since we\u2019ve had to worry what it\u2019s all about.\u00a0For the moment listen to this tale as CPHS members Cy Eid and Milan Zahorcak try\u00a0to make a photograph using an early American wet-plate camera fitted with a late\u00a01850s portrait lens.<\/p>\n

“The intrepid duo set up their gear in a kitchen with the scene lit by bright but diffused daylight. The subject is a tabletop setting of ancient photographic equipment at a\u00a0carefully measured distance of 10 feet from the film plane.<\/p>\n

“The image is carefully composed and focused with utmost care using an 8x magnifier. The plate holder is inserted, the slide removed for a timed exposure of four seconds, the slide returned and holder removed.<\/p>\n

“Within minutes, the film \u2013 in this case ordinary \u201cpolycontrast\u201d darkroom paper for test\u00a0purposes, was developed and \u2013 what the heck! <\/b>\u2013 found to be grossly out of focus. You can\u00a0imagine the puzzled looks and head scratching that followed. The camera was checked, the\u00a0ground glass re-examined but the focus was perfect \u2013 not just close but perfect.<\/b>” …<\/p>\n

Members read the rest of the article, including the solution to the focussing issue in the issue 26-1 pdf file on the free members only DVD\/thumb drive. Join using the notes above and at right. Email membership queries to member@phsc.ca<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Toronto. Consistent with editor Lansdale’s inspiration to celebrate our 25th anniversary, the folks at the Cascade Panorama Historical Society sent in a juicy article by Milan Zahorcak titled, “What the …?”. Milan describes the problem raised when an old lens … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1944],"tags":[398,401,692],"class_list":["post-33026","post","type-post","status-publish","format-standard","hentry","category-history","tag-camera","tag-lens","tag-process"],"_links":{"self":[{"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/posts\/33026","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/comments?post=33026"}],"version-history":[{"count":2,"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/posts\/33026\/revisions"}],"predecessor-version":[{"id":33030,"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/posts\/33026\/revisions\/33030"}],"wp:attachment":[{"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/media?parent=33026"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/categories?post=33026"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/phsc.ca\/camera\/wp-json\/wp\/v2\/tags?post=33026"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}