[OM] cokin filters

[John Hudson]

Are there any cokin filter users, or others, on the list who can opine as to 
the quality of cokin filters and any resulting image degradation as compared to 
using high quality optical glass filters? Just off the top of my head I have to 
think that cokin's plastic filters result in greater image degredation than 
high quality B+W and Heliopan filters for example and also are more prone to 
scratching than glass filters. 

John Hudson