{"product_id":"pinhole-lens-board-compatible-with-all-helicoid-lens-cones-not-mamiya-press-holga","title":"Pinhole Lens Board - Compatible with all helicoid lens cones (not Mamiya Press\/Holga)","description":"\u003cp\u003eThis is a replacement threaded lens board, in either standard (M65) or large (M77) helicoid mount. The pinhole lens board contains a professionally laser drilled high quality brass pinhole plate with a standard 49mm filter thread and push on lens cap.\u003c\/p\u003e\n\u003cp\u003eThe pinhole can be configured in either 0.2mm or 0.4mm diameter, which is combined with the lens cone to calculate the effective aperture (F number) for metering. \u003c\/p\u003e\n\u003cp\u003eFor example, if the lens cone you are using is for a 90mm lens, you would divide the focal length by the pinhole diameter to obtain the F number;\u003c\/p\u003e\n\u003cp\u003e90 \/ 0.2 = 450\u003c\/p\u003e\n\u003cp\u003e90 \/ 0.4 = 225 \u003c\/p\u003e\n\u003cp\u003eYou would then use this F number with your film ISO to meter the scene. As the pinhole is mounted to a focusing helicoid, you can also extend the cone by up to 14mm to adjust the equivalent focal length (re-calculating your F number too).\u003c\/p\u003e\n\u003cp\u003eThe push on lens cap is used a traditional simple shutter. Alternatively, cover the pinhole with your hand before removing the lens cap and use your hand as a shutter.\u003c\/p\u003e","brand":"Chroma Camera","offers":[{"title":"0.2 \/ M65 (65mm thread)","offer_id":65080211800441,"sku":null,"price":46.0,"currency_code":"USD","in_stock":true},{"title":"0.2 \/ M77 (77mm thread)","offer_id":65080211833209,"sku":null,"price":46.0,"currency_code":"USD","in_stock":true},{"title":"0.4 \/ M65 (65mm thread)","offer_id":65080211865977,"sku":null,"price":46.0,"currency_code":"USD","in_stock":true},{"title":"0.4 \/ M77 (77mm thread)","offer_id":65080211898745,"sku":null,"price":46.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0668\/4747\/3939\/files\/DSC05840-Photoroom.jpg?v=1793629277","url":"https:\/\/chroma.camera\/en-us\/products\/pinhole-lens-board-compatible-with-all-helicoid-lens-cones-not-mamiya-press-holga","provider":"Chroma Camera","version":"1.0","type":"link"}