OM-2n Meter Low-Light Reading

<p>The meter of the OM-2n was guaranteed as being able to produce consistently accurate readings in low-light conditions up to -6.5EV in the auto mode (i.e., an exposure of 120sec.), which far exceeded the capabilities of all other SLRs of its age. But, is anyone aware of any report about the practical limit for low-light readings, even without a guarantee for consistent results? </p>

 

<p>An OM-2 or OM-4 will expose for way longer than two minutes - remember it's real time metering - so the camera doesn't "know" what the exposure is required when it opens the shutter. Shutter opens - mirror box-mounted metering cell measures light reflecting off film surface until the meter determines that the requisite amount of light has been captured, then it signals the shutter to close. I've seen OM-2s expose on moonless nights for ~15 min on auto - pretty heavy on the batteries, though. I don't know why there's a quoted "guaranteed" exposure up to 2 minutes - it's possible that reciprocity failure renders the exposure a little suspect at extremely low light levels - I don't know if a meter could compensate for this.</p>

<p>Go for an OM-2 over a 2n... here is the verdict from the OM FAQ<br>

http://brashear.phys.appstate.edu/lhawkins/photo/olympus.faq.html#ques_B8</p>

 

<h3>B8) What are the differences between an OM-2 and an OM-2N?</h3>

<p>In addition to the new features of the OM-1N, the OM-2N has <br /> an exposure compensation warning flag, full-frame averaging<br /> at all shutter speeds, and 120 second exposure limit on<br /> auto. The OM-2 limit was stated as 60 seconds in the manual, <br /> although at least one person reports that this is not a hard <br /> limit --- his OM-2 shutter will stay open as long as required.<br /> If someone who actually has an OM-2 could confirm this, it would<br /> be appreciated.</p>

<p>Plain OM-2 low light auto exposure will go as long as 19 minutes when set to asa 12. The higher the asa setting, the shorter the auto exposure. This is due to the "off limiter", an LED at the base of one of the SBC cells. The LED glows to close the shutter prematurely if the shutter is fired accidentally with the lens cap on. The 2N book says auto exposure is good to 2 minutes (at all asa settings) but will (in most cases) expose to about 3.5 minutes. John</p>

<p>Thank you all. The way I understand the manual is, Olympus guaranteed that up to an exposure time of 120 sec. all photos taken under the same light conditions would always and consistently produce the same results. I assume that this implies with longer exposure times, there could be variations. I don't this this refers to the reciprocity problem, but rather to how the meter reads under very low light conditions. That is, beyond 120 sec. readings start getting approximated.</p>

<p>You also have to figure in film reciprocity failure. That is, the more exposure a film gets, the less sensitive it becomes. John</p>