Apparatus for imaging a sample, said apparatus comprising: illumination means (101, 102, 103, 104, 105, 106, 107, 108) for illuminating said sample simultaneously in a line focus or an array of foci; and detection means (108, 107, 106b, 111, 112, 113) for detecting photons emitted or scattered from the sample simultaneously in an array of fields of view; wherein an array of sub-observation volumes in the sample, from which photons are emitted or scattered during imaging, is defined by the volumes in space where the line focus or array of foci from the illumination means (101, 102, 103, 104, 105, 106, 107, 108) overlap with the corresponding array of field of views of the detection means (108, 107, 106b,111, 112, 113); wherein the apparatus comprises a cylindrical sample holder (110, 110a) configured to hold the sample at the lateral surface thereof, said cylindrical sample holder (110, 110a) being rotatably arranged such that at least a portion of said sample can be transported through at least one of said sub-observation volumes by rotating the cylindrical sample holder (110, 110a); and wherein the central axes of the line focus or array of foci from the illumination means (101, 102, 103, 104, 105, 106, 107, 108) and the corresponding array of field of views of the detection means (108, 107, 106b, 111, 112, 113) are substantially parallel; characterized in that the apparatus further comprises a coating device arranged in close proximity of an outward facing surface of the cylindrical sample holder for spreading a liquid layer on the outward facing surface of the cylindrical sample holder (110, 110a) during rotation. illumination means (101, 102, 103, 104, 105, 106, 107, 108) for illuminating said sample simultaneously in a line focus or an array of foci; and detection means (108, 107, 106b, 111, 112, 113) for detecting photons emitted or scattered from the sample simultaneously in an array of fields of view; wherein an array of sub-observation volumes in the sample, from which photons are emitted or scattered during imaging, is defined by the volumes in space where the line focus or array of foci from the illumination means (101, 102, 103, 104, 105, 106, 107, 108) overlap with the corresponding array of field of views of the detection means (108, 107, 106b,111, 112, 113); wherein the apparatus comprises a cylindrical sample holder (110, 110a) configured to hold the sample at the lateral surface thereof, said cylindrical sample holder (110, 110a) being rotatably arranged such that at least a portion of said sample can be transported through at least one of said sub-observation volumes by rotating the cylindrical sample holder (110, 110a); and wherein the central axes of the line focus or array of foci from the illumination means (101, 102, 103, 104, 105, 106, 107, 108) and the corresponding array of field of views of the detection means (108, 107, 106b, 111, 112, 113) are substantially parallel; characterized in that the apparatus further comprises a coating device arranged in close proximity of an outward facing surface of the cylindrical sample holder for spreading a liquid layer on the outward facing surface of the cylindrical sample holder (110, 110a) during rotation.