don and david, the film formats are roughly sequential. if multiple formats were introduced in a single year, the larger image size tends to get the higher number. rollfilm formats begin with '1', the exceptions being 620, 616, 220 and 828 (i'm not aware of any others). kodak justified the 620 and 616 formats by claiming they would allow for less bulky cameras, but only really ever made one camera to back that up: the Special 620. the monitors, vigilants, seniors, tourists, etc. were all rather bulky compared to their 120 film competitors, such as the voigtlanders. --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list