Carl Zeiss did a research about the film flatness using 220 and 120 film: http://tinyurl.com/35kmksu http://www.zeiss.de/C12567A8003B58B9/ContentsWWWIntern/134AEE504E89CD50C12569620039712C --- 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