\n
There are two classes of shutters: focal and aperture. Focal shutters
\nare located near the plane of the film and light the entire frame of film. Aperture shutters are located near or\u00a0inside the lens. Such a shutter blocks the light, being closet to the\u00a0lens than the film. This shutter can have be smaller, comparable to the size\u00a0of the lens glass. That is why such a shutter can be much cheaper than
\na focal shutter.<\/p>\n
\u00a0<\/span><\/p>\n The most commonly used aperture shutter option is the\u00a0central shutter. It blocks the light with the help of 3 or 5 movable\u00a0leaves, which, moving during operation, first open and then close the\u00a0round hole. Central shutters were invented more than a century ago. This\u00a0is one of the first types of shutters used on early cameras.<\/span><\/p>\n \u00a0<\/span><\/p>\n Such a shutter has one big minus \u2013 the insufficient value of\u00a0the fastest shutter speed. Opening and closing of the leaves (they have\u00a0inertia) takes time. The leaves start moving from the closed position,\u00a0then brake to a complete stop in the open position, and then start\u00a0moving in the opposite direction.<\/span><\/p>\n \u00a0<\/span><\/p>\n It seems to be a simple process, but\u00a0the fastest shutter speed of such a shutter is 1\/250. This value of\u00a0the fastest shutter speed was normal for photographic materials of 100 years ago. Today’s photographic materials have higher light\u00a0sensitivity, and today we need a shutter with a faster shutter speed.\u00a0Also, the central shutter has to be installed inside or directly\u00a0behind the lens. Only in this case the exposure across the frame will\u00a0be even. If we move the central shutter to the film plane, the frame \u00a0<\/span><\/p>\n But we are making a camera for a wide range of lenses! And we don’t know exactly where the rear lens of a particular lens will be. So, the aperture shutter is not suitable for our camera. In general, it is impossible to apply it. There is only one option left\u00a0<\/span>for our universal camera – a focal plane shutter placed directly in\u00a0front of the film.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":" There are two classes of shutters: focal and aperture. Focal shutters are located near the plane of the film and light the entire frame of film. Aperture shutters are located near or\u00a0inside the lens. Such a shutter blocks the light, being closet to the\u00a0lens than the film. This shutter can have be smaller, comparable to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":17,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-198","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=\/wp\/v2\/pages\/198","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=198"}],"version-history":[{"count":2,"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=\/wp\/v2\/pages\/198\/revisions"}],"predecessor-version":[{"id":312,"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=\/wp\/v2\/pages\/198\/revisions\/312"}],"wp:attachment":[{"href":"https:\/\/x35project.com\/WP\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=198"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nwill be exposed unevenly: the centre of the frame will be exposed more\u00a0than the edges.<\/span><\/p>\n