A method of analysis of nano-objects using wide-field bright field transmission techniques comprising: acquiring a plurality of images of a sample comprising a plurality of nano-objects using bright field illumination via a continuously variable spectral filter; identifying a nano-object within the sample in the plurality of images, wherein: the position of the nano-object within a first image of the plurality of images is in a first position, the position of the nano-object in a second image of the plurality of images is in a second position, in the second image the nano-object is absent from the first position, and the first and second positions are different; quantitatively determining, using a transmitted intensity extracted from the plurality of images, an extinction cross-section of the identified nano-object, wherein: a. the nano-objects are immobilized on a substrate and the method further comprises moving the substrate relative to imaging apparatus to acquire the plurality of images, or b. the nano-objects are in suspension in a carrier fluid and the method comprises restricting the motion of the nano-objects by: i. changing the viscosity of the solution; ii. applying electrophoresis to pull nano-objects towards a surface, measuring the nano-objects and repelling the measured nano-objects from the surface by applying an opposite electric field; or iii. providing a functionalised surface to temporarily secure at least one nano-object. acquiring a plurality of images of a sample comprising a plurality of nano-objects using bright field illumination via a continuously variable spectral filter; identifying a nano-object within the sample in the plurality of images, wherein: the position of the nano-object within a first image of the plurality of images is in a first position, the position of the nano-object in a second image of the plurality of images is in a second position, in the second image the nano-object is absent from the first position, and the first and second positions are different; the position of the nano-object within a first image of the plurality of images is in a first position, the position of the nano-object in a second image of the plurality of images is in a second position, in the second image the nano-object is absent from the first position, and the first and second positions are different; quantitatively determining, using a transmitted intensity extracted from the plurality of images, an extinction cross-section of the identified nano-object, wherein: a. the nano-objects are immobilized on a substrate and the method further comprises moving the substrate relative to imaging apparatus to acquire the plurality of images, or b. the nano-objects are in suspension in a carrier fluid and the method comprises restricting the motion of the nano-objects by: i. changing the viscosity of the solution; ii. applying electrophoresis to pull nano-objects towards a surface, measuring the nano-objects and repelling the measured nano-objects from the surface by applying an opposite electric field; or iii. providing a functionalised surface to temporarily secure at least one nano-object. a. the nano-objects are immobilized on a substrate and the method further comprises moving the substrate relative to imaging apparatus to acquire the plurality of images, or b. the nano-objects are in suspension in a carrier fluid and the method comprises restricting the motion of the nano-objects by: i. changing the viscosity of the solution; ii. applying electrophoresis to pull nano-objects towards a surface, measuring the nano-objects and repelling the measured nano-objects from the surface by applying an opposite electric field; or iii. providing a functionalised surface to temporarily secure at least one nano-object. i. changing the viscosity of the solution; ii. applying electrophoresis to pull nano-objects towards a surface, measuring the nano-objects and repelling the measured nano-objects from the surface by applying an opposite electric field; or iii. providing a functionalised surface to temporarily secure at least one nano-object.