rtomcala@xxxxxxxxxxx writes:
<< With the release of
the OM2n, they added a small led in the viewfinder that added to the
exposure and limited the long exposures to about 2 minutes. This is
why, although I love my Om2n, I keep my OM2 also. The OM2 may be hard
on the batteries during long exposures, but it gets the shot !
>>
Rand,
Both the OM2 and 2N have led limiters. Their operation actually
causes exposure errors for very long exposures in both cameras but the errors
only start after 2min in the 2N. And the maximum time does not go to a lot
longer than 2min. The 2N exposure cycle only differs from the 2 in that an
analog timer delays the on-set of when the led is switched on and also the
led is brighter causing the limiter to act quickly once switched on. The
brighter LED is also more reproduceable over temperature etc so the limiting
action time has a much tighter tolerance and does not contribute errors below
the 2min timer limit. On the other hand the OM2 led limiter forces the camera
to act as if there is a fixed very low light in the scene over most of the
exposure cycle instead switching in only after 2min. Since exposures are log
light intensity related the OM2 errors introduced only become very
significant when the led level and the scene light level are getting to be
similar in magnitude. The OM2 more gradual limiting action does allow for
significantly longer exposure times but the limiter does eventually add
significant errors although by that time film reciprocity is probably a much
bigger problem.
>> Tim Hughes <<
>> Hi100@xxxxxxx
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