{"product_id":"svbony-sv109-m48-variable-extension-tube","title":"SVBONY SV109 M48 Variable Extension Tube (24–35 mm)","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9180b_20250807085907_6375_20260814155301_2979.webp?v=1791670117\" alt=\"SVBONY SV109 M48 variable extension tube\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe SVBONY SV109 M48 is a variable-length extension tube with M48×0.75 male and female threads. Its length adjusts from 24 mm to 35 mm, so you can dial in the exact spacing a reducer or field flattener needs instead of stacking fixed spacers. It is anodized aluminium, internally designed to cut stray light, and weighs 28.3 g (1.00 oz).\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you image through an M48 reducer or flattener and want to fine-tune backfocus, or if you need to adjust focus position or image scale in an M48 train.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9180b-1_20250807085907_4252.jpg?v=1791670118\" alt=\"SVBONY SV109 M48 variable extension tube detail\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdjustable 24–35 mm:\u003c\/strong\u003e an 11 mm range of continuous spacing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM48×0.75 male and female threads:\u003c\/strong\u003e fits standard M48 imaging trains.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStray-light control:\u003c\/strong\u003e internal design reduces reflections.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnodized aluminium:\u003c\/strong\u003e 28.3 g.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus tuning\u003c\/strong\u003e behind M48 reducers and field flatteners, where corner star shape depends on the spacing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocus reach and image scale\u003c\/strong\u003e adjustments in camera and eyepiece trains.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9180b-2_20250807085907_6366.jpg?v=1791670117\" alt=\"SVBONY SV109 M48 variable extension tube threads\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreads:\u003c\/strong\u003e M48×0.75 male and female, per SVBONY's key features. (The vendor's secondary feature list also mentions T2 threads; the M48 figure is the one in the product title and key features.)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpacing:\u003c\/strong\u003e add 24–35 mm to your camera's flange distance and any filter drawer to reach your corrector's backfocus. Send us your setup and we will work the figure out with you.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMechanical spacer only:\u003c\/strong\u003e no glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMinimum length 24 mm:\u003c\/strong\u003e for shorter gaps, fixed M48 spacers are the option.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. Thread it into your train, set the length to the spacing you need, and lock it in place.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the adjustment range?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e24 mm to 35 mm.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs there an M42 version?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes, SVBONY makes the SV109 in an M42 (T2) version as a separate product.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 28.3 g anodized aluminium M48×0.75 extension tube that adjusts from 24 to 35 mm for precise backfocus and focus spacing.\u003c\/p\u003e","brand":"SvBony","offers":[{"title":"Default Title","offer_id":67722228039791,"sku":"F9180B","price":25.64,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9180b_20250807085907_6375_20260814155301_2979.webp?v=1791670117","url":"https:\/\/ontariotelescope.com\/products\/svbony-sv109-m48-variable-extension-tube","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}