Quality Planoconcave lenses Planoconcave lenses have one inward curved face and one flat face. Planoconcave lens bend parallel input rays so that they diverge away from one another on the output side of the lens. They have a negative focal length.  Planoconvex lenses are mainly used for image reduction or to spread light. Planoconcave lenses are also known as a tube-length correction lens in microscopy and as a Barlow lens in astronomy. These Planoconcave lenses are stocked uncoated or with a multilayer AR coating for 450-900nm except SF11 which are SLAR.
Knight Optical > Lenses > Concave lenses - Quality Grade Uncoated This is the section containing Uncoated. AR coated 450-900nm This is the section containing AR coated 450-900nm. Only UK and EU customers are charged VAT at 17.5%, customers outside the EU and EU customers based outside the UK who have a valid EU VAT number will not be charged VAT Bulk Discounts! Where (B) appears next to a price below, bulk prices are available, click the (B) button to view! Knight Optical > Lenses > Concave lenses - Quality Grade
Specification   Material: BK7 (or B270), SF11 for lower spherical aberrations (See spherical aberration calculation section) Material Data: (see materials section)  Diameter: +0.0 / -0.10mm  Centration Accuracy: < 0.1mm (F.L 40mm) < 2.5mrad (F.L > 40mm)  Focal Length (@587nm): ± 0.2% (<10mm) ± 2.0% (10-1000mm)  Centre Thickness: ± 0.15mm  Surface Quality: <40-20 scratch/dig (see quality section)
Specific requirements We can manufacture Planoconcave Lenses to any size or focal length at short notice, so if your requirements are not listed please contact us by telephone/ fax or email: stockrequirement@knightoptical.co.uk Coating Planoconcave lenses with suffix “AV2” are coated on both faces with (multilayer antireflective coating <0.5%@450-900nm, except SF11 which have a SLAR (see coatings section). Options available   · Mounting (all items)   · Special AR coating   · Stock lenses can be edged to smaller diameters See also Negative Doublets: Achromatic Doublets