Preparing for the next travel adventure i found that my copy of this lens had serious issues opening up the aperture blades, they would stick and only move very slowly,,,
Since it's such a nice performer in Infrared I investigated the cause, after total disassembly I could see that the grease had seeped into almost all moving parts of the internals except the aperture blades themselves. The slow movement was cause by the aperture blade actuation disc was filled with stick grease residue - The blades and aperture blade area had somehow not been contaminated.Not too bad except for the time,,,
