I don't have a VX125 now to compare, but the VX23D is significantly smaller. The VX23D standards are 250mm tall, 190mm wide and 50mm thick, including the knobs, etc. The focusing screen adds around 25mm depth to the rear standard, The whole camera, in ready to shoot configuration, along with a couple of lenses and film holders would easily fit in a 30x25x25 shoulder bag for 35mm SLRs.