I guess I need a little education here. I always assumed that with respect
to a lens snappy meant that the action of the diaphragm in stopping down and
opening back up was very quick, with no hesitation. My first Vivitar Series
1 28-90 after years of faithful service seemed to stop down as quickly as
ever but would open back up when it felt like it (which would always be
several to many seconds later). At the time I was told that this was called
a sticky diaphragm. That particular lens now gathers dust in my bag.
Fast forward now. I acquired one of the > 1,000,000 serial number f1.4's in
an eBay auction. It stops down quickly (at least subjectively) but in
opening back up, the diaphragm blades seem to glide back into open position.
This takes some noticeable time (but well less than a second). I came
across a 50mm f1.2 Zuiko (graded E) on KEH's site late last week, ordered
it, and received it yesterday. Same diaphragm action as with the f1.4.
In checking for a sticky diaphragm, I've always used the DOF preview button.
My older Zuiko lenses stop down and open back up very abruptly. The action
is audible. I hear nothing when I push and release the DOF button on the
other two lenses. Opening back up takes several times as long as the
stopping down action. I don't see any oil within the lens. Has lens
technology moved forward and this is the way modern lenses should act?
I would appreciate any comments about what is going on with those lenses as
well as a more rigorous definition of "snappy." If there is a problem with
the lenses, is it something to be concerned about? It's way too late to do
anything about the eBay lens but I do have 60 days to return the f1.2 to KEH
for repair or credit.
Thanks much.
Mike
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