| Author | Message | ||
     Glenn Tinkerer Username: Glenn Post Number: 87 Registered: 07-2006 Rating: N/A |
Like Rick I do not know this lens, however I have worked on a number of Sigma lenses and think I understand their design philosophy. For all mount types the basic optical cell/focus barrel is the same, as is the aperture linkage. The individual mounts are just 'hung' on the back of this complete unit. This mount unit contains all the required linkage to transfer the aperture operation, from camera to lens and any 'registration' corrections required. There may be very simple additions - an actuating lever - added to the main unit, but nothing drastic. Commonality is the only way that lens manufactures can keep their costs down. I know the inclusion of molded plastic parts is also quoted, but a vast parts inventory is a recipe for disaster in the third party lens business. This is especially so if you are producing lenses which have excellent optical performance, something that Sigma has always striven for. |