On my 23C, I can adjust the spacing of the condensers for different formats (35mm - 6x9). If I'm doing 35mm with a 50mm lens, I can and often do just leave it on the 6x9 setting. The light distribution is even across the whole field, just not as bright as if it were on the 35mm setting. So, printing times are longer, but I don't have a problem with long printing times at all. Often, the opposite.