Most plain 2s give a low light exposures as long as 19 minutes at ISO
12, 9.5 min. @ iso 25, 4.5 min. @ iso 50 etc. A 6 hour exposure would
be with a defective camera (auto limiter LED not working) :-0
John
Wayne Harridge wrote:
>
> David wrote:
>
> > It's really based on measured EV rating, I think, rather than time. So
> > you'll get longer exposures with slower film, at least within some
> > limits, and of course, this doesn't take into account reciprocity
> > failure. Here's the specs I have:
> >
> > OM-2 60sec @ ASA100 (approx -5 EV)
> > OM-2n 120sec @ ASA100 (approx -6 EV)
> > OM-2sp 120sec @ ASA100 (approx -6 EV)
> > OM-4 240sec @ ASA100 (approx -7 EV)
> > OM-4Ti 240sec @ ASA100 (approx -7 EV)
>
> I did some tests with my OM-2n and got the following results using a body
> cap (ie. no light):
>
> ISO 100 3 Min 48 Sec
> ISO 1600 3 Min 44 Sec
> ISO 25 3 Min 48 Sec
>
> The thing to keep in mind is that even though it gives you a long exposure
> there is no guarantee of the accuracy. My guess is that with very low light
> levels, leakage currents within the exposure/timing circuit probably have a
> major contribution in determining the actual length of the exposure.
> Perhaps the "spec" is the longest exposure for which the exposure/timing
> circuits are reasonably accurate.
>
> >
> > None of the amature series OMs need apply (they're around around 0EV,
> > maybe 2sec at ASA100).
>
> I got the following results with my OM-10
>
> ISO 100 8 Sec
> ISO 1600 <2 Sec
> ISO 25 26 Sec
>
> Wayne Harridge
> Ivanhoe, Victoria, Australia
> http://www.geocities.com/Paris/Louvre/6152/
>
> < This message was delivered via the Olympus Mailing List >
> < For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
> < Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|