Use the Hasselblad Converter H1,7x to extend the focal length by 1.7. E.G. it will turn a 100mm into a 170mm lens. Keep in mind that also the aperture will be factoriszed. The Converter H 1.7x (3023717) increases the focal length of a lens by a factor of 1.7x. It features the same outstanding optical and mechanical quality as the elements in the Hasselblad H-lens series. All the glass-to-air surfaces have a multi-layer coating to reduce internal reflections and increase the efficiency of the opti- cal system. The aperture reduction is -1.5 stops. The Converter H 1.7x can only be used together with Hasselblad H lenses. Attempts to attach any other type of lens may cause damage. General The Converter H1.7x is compatible with all H lenses except the following: • HCD 4.8/24mm (3023024) • HCD 4/28mm (3023028) • HC3.5/35mm(3023035) • HC 4–5.5 / 35–90mm Zoom (3023590) • HC3.5–4.5/50–110mmZoom(3023511) • PleasealsonotethattheAFfunctionoftheHCMacro120mmandtheHC 300mm is disabled when used in conjunction with this item. The converter can be attached either to the lens first or to the camera body first, whichever is preferred. The converter can also be used in combination with extension tubes, though it should be mounted between the camera body and extension tube or combination of tubes.