Remember this is a constant f/3.5 aperture design. Thus the aperture blades adjust during zooming to make the aperture f/3.5. At the wide end, the aperture opening is circular, at 86 mm, the blades will show.
i don't think mine does that...
it's a bit polygonal at every FL wide open
it is not obvious but it is there. I tried rotating the rotation plate before and after I rebuilt the iris assembly and it's still the same. this is the 2nd time that I encountered this. the first one was on the 5.5cm f/3.5 which was easily fixed by drilling and tapping to make a new hole for the aperture post. this one is a bit difficult since the blades are actually extending
it is not obvious because the rear elements actually hide the extra bit, but you can still see it if you peek carefully. maybe it does not affect the actual f/stop?
HAW_7387 by
mrBabaero, on Flickr
this lens is actually a pretty good walk around lens in that it gives you some flexibility. If i was using a 50 something prime just like everyday, this shot would have ended looking a lot different, 86mm gave me the ability to isolate the subject a bit as well as give me some distance so that he is not aware of what i am doing
PS: this is the dirtiest lens that i have cleaned so far. looks like you can bake a bread with it!