Albert Yang wrote:
Is the OM-2n better? Should I be bidding on an OM-2n instead of an
OM-1n? Thank you all for the links you've sent me, today is my first
day on the list, and I feel very welcome.
What exactly is TTL OTF? I see that the OM-2n has it, but I'm not
quite sure what "it" is... Also, I see the selection for exposure
having a "manual" and an "auto". What exactly does that mean? What
does the "auto" do??
I'm just wondering because if the prices on ebay are close, should I
go after the OM-2n then?
=======================================================================
Albert, you are indeed welcome.
To me, the OM-2(n) is the better camera but there are many who prefer
the OM-1(n) because of its mechanical shutter and, in some cases,
because it was the first OM camera.
TTL just means that the light is metered 'through the lens' - most SLR
cameras use a photocell or two that monitor the light from the focusing
screen under the pentaprism. Cameras that use this method are 'blind'
once the shutter is released and expose (in AE mode) based on the
reading taken just before the exposure started. If the light changes
during the exposure, the camera cannot do anything about it. The
OM-1(n) and the OM-2(n) both use CdS cells at the focusing screen to
give the meter reading. The reading can be off if stray light enters
the viewfinder.
OTF means 'off the film' - in OM-2(n) cameras, an additional pair of
photocells in the floor of the mirror box looks back at the shutter
curtain, which is patterned with black and white square dots to be
similar in reflectance to the surface of a typical unexposed film. When
the shutter is released in 'auto' mode, the OTF measurement begins. For
short exposures, the measurement is taken only from the shutter
curtain. For longer exposures, some measurement is taken from the
surface of the film whilst the shutter is open.
The camera is not 'blind' during exposure and can adjust the shutter
speed if the light changes during the exposure. Only fast-reacting
photocells can be used effectively for OTF, which explains the use of
silicon blue cells in the OM-2(n). With the OM-2(n) in auto mode, only
the SBC cells are used to control the exposure, even though the CdS
cells are responsible for the meter reading.
Light measurement in OM-2(n) and higher models is superbly accurate.
Auto mode, in my opinion, is the 'native' mode of the OM-2(n). One of
its special characteristics is a very long maximum exposure of 2+
minutes, enabled by the OTF technique (auto mode only); another is TTL
flash control, using an Olympus dedicated flash unit, which directly
controls the duration of the flash based on the camera's OTF reading.
Hope this helps,
Regards
=====
Ray
"The trouble with resisting temptation is
you never know when you'll get another chance!"
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