A spectroscopy method in which a sample is scanned without moving the sample. Light from the sample 16 is collected by a lens 14 and analyzed at a spectrum analyzer 28 before being focused onto a photodetector 32. Light from the focal point of the lens 14 is brought to a tight focus on the photodetector 32 whilst light from in front of or behind the focal point comes to a more diffuse focus. Light from the pixels on the photodetector 32 corresponding to the focal point of the lens 14 is processed, whilst light from pixels outside this region is ignored, thus forming a `virtual slit`. The sample 16 is scanned in a vertical direction by moving the `virtual slit` up and down, by changing the designated rows of pixels from which data is analyzed. The sample is scanned in a horizontal direction by moving a vertical slit 24 in the light path in a horizontal direction.