A laser detector apparatus (1) is provided, where a pixel array (3) is arranged behind a lens arrangement (4) such that distant objects (9) (in general, those at infinity) are out of focus at the pixel array. The image from the pixel array is evaluated by a computer processor (6) to detect such out of focus images which will be of a known size and shape (generally circular spots of known width). This can enable distant laser threats to be readily distinguished from nearby bright objects (10), whilst also protecting the pixel array from powerful laser sources (because the laser energy is not focussed to a point, on the pixel array it is less likely to damage the pixel array). It can also enable the wavelength of the laser to be accurately determined from the ratio of colours in the image of the laser spot, because it will typically not be a saturated image. The apparatus and method are particularly suitable for identifying and distinguishing laser sources across a wide range of brightnesses, and is also suitable for detecting and distinguishing multiple laser sources.