Blog / Learn & Help / Lenses Some S-35 zooms already cover FF (you just didn’t know this!) Lenses This is an extremely brief article to help to explain a lesser-known but extremely valuable tip. In summary, film zooms designed to cover S-35 sensors, will also cover Full Frame as well IF used with a 1.5x extender and this is built into several zoom lenses already, such as the Canon Cabrio zooms. In English, this means that you can use Full Frame cameras with existing PL zooms without needing external image expanders. Canon Cabrio S-35 zooms all include the built-in 1.5x extender facility, to extend the focal length by 1.5x by means of activating a 1.5x rocker knob and in doing so, cover Full Frame sensors. Sometimes, we need to hear things several times in order to fully appreciate how useful they are and so it is with the 1.5x lens extension function, which I realised recently not only ‘zooms-in’ by a factor of 1.5 but also necessarily increases the image size, enabling images to cover Full Frame sensors. The 3 x Canon Cabrio S-35 zooms below all include the built-in 1.5x extender facility, so that images can be both ‘zoomed-in’ and subsequently, also cover Full Frame simply by using the 1.5x rocker knob. Canon CN7x17 (17-120mm, which converts to 25.5-178.5 with 1.5x extender)Canon CN20x50 (50-1000mm, converts to 75-1500mm with built-in 1.5x extender)Canon CN10x25 (25-250mm, which converts to 37.5-375 with 1.5x extender) When used normally (without the 1.5x extender), S-35 zooms will vignette when used with a FF sensor. When the 1.5x extension is engaged, image focal lengths increases by a factor of 1.5 and will cover FF. You can of course use a PL lens extender to achieve this as well. VMI stock 2x converters which will both double the focal length and ensure that the resulting images cover Full Frame. IBE 2x PL converterMTF 2x PL converter When using lens extenders, sensitivity will reduce The laws of optics necessarily dictate that if you enlarge an image, then the brightness of the image will also reduced, so the camera operator must be made aware that if the 1.5x extender is used, then the maximum iris of the lens reduces by 1.5x as well. Some examples using built-in 1.5x converter: Canon CN7 lens: 17mm/T2.95 in S-35, becomes 25.5mm/T4.4 with 1.5x extender and covers FF.Canon CN10 lens: 25-187mm/T2.95 (to T3.95 at 250 mm) in S-35, becomes 37.5-375mm/T4.4 at 37.5 – 281 mm (to T5.9 at 375 mm) with 1.5x extender and covers FF.Canon CN20 lens: 50-560mm/T5 (to T8.9 at 1000 mm) in S-35, becomes 50-560mm/T7.5 (to T13.35 at 1500 mm) with 1.5x extender and covers FF. Some examples using external 2x PL converter: Angenieux Optimo 15-40/T2.8 in S-35, becomes 30mm-80/T5.6 with 2x extender and covers FF.Angenieux Optimo 45-120/T2.8 in S-35, becomes 90mm-240/T5.6 with 2x extender and covers FF.Angenieux Optimo 24-290/T2.8 in S-35, becomes 580mm-240/T5.6 with 2x extender and covers FF. Note that external 1.5x converters are also available to achieve lesser magnification and stop loss. Barry Bassett, March 2021Images of rocker and lens charts are courtesy of CVP Related articles Macro and Micro Cinematography Cinematography, Lenses We all love to see images of extreme magnification to show a world which we can’t experience with our own eyes but just like all cinematography, this is hard to do well. The choice right lens for the specific shot is key and this article aims to explain the differences between Close Up, Macro and Micro photography/cinematography and in particular, to introduce the cinematographer to a relatively recent new type of lens, which are called Nelsonian Lenses made by Infinity Photo-Optical and which use microscope techniques to create unique images which are not possible using traditional optics. Beginner’s Guide to Depth of Field Cinematography, Lenses This article is written mainly for those who want to know the very simple concepts which allow camera operators to manipulate the Depth of Field in order to make them look more cinematic. An account of a successful Sigma Lens Day held on 13 February 2020 at VMI Lenses VMI held a Sigma lens day on 13 February 2020 in London.