The MAXI version of the IMAGING-PAM M-Series employs a very compact and powerful 300 W LED array for homogeneous illumination of up to 10 x 13 cm areas (microtiter plates) with pulse-modulated excitation, actinic light and saturation pulses. IMAG-MAX/LR (red measuring light version, 650 nm, e.g. for cyanobacteria) no additional filter plate needed by measurements with mirror-surface properties.