Hi! As I was reading about some lenses like the Hexanon 135mm the author kept mentioning that the built in hoods were a bit shallow and that adding and extra hood accessory helps to increase contrast etc. Have you guys done that? I was thinking on getting some for my 200, 300 and 135mm lenses that only have the built in ones. Not even sure how that works...I guess like adding a rubber hood to the metal hood for example. Thanks!