The Measurement of light sources of feeble intensity reguires special detectors. Two new photomultipliers suitable for such measurements are described. The 9870, ‘bulls-eye’, photomultiplier has a quasi-spherical cathode with nearly 2 π collection efficiency. The cathode shape provides isochronous collection over the pbotocathode area. This tube is used for large volume Cerenkov detectors. The 9863 is a fast, linear focused photomultipliers with a cathode of small effective area, and is used where the light can be suitably focused. The tube has a large dynamic counting range and has general application in photon counting. The low afterpulse performance when used with fast, digital correlators is discussed. Copyright © 1978 by The Institute of Electrical and Electronics Engineers, Inc.