Chuck, Piere, John:
Thanks for your input. When I say that I can't read the needle, it means
my challenge is that I cannot tell whether I can use auto (ie, less than
3.5 mins at the chosen aperture) or not. I really need to get a handle
on whether I can or I need to go with "B" plus timer.
The workaround for the digital guys (and gals) was (depending on
camera), jack the iso and aperture until they could get a reading. Then,
calculate backwards (mentally) based on desired iso and aperture. That's
something that I figured I would have to do with a meter. I've found two
used meters available locally - a 358 and a Gossen Luna Pro F. One is
backlit, the other will memorize the reading (read with
torch/flashlight).
I don't have a problem doing the back calculation - as long as I know
that starting point. And, yes, there's reciprocity failure to take into
consideration. The latitude of Portra helps in that regard. Again,
without a light reading, I can't calculate RF either (as far as I can
tell).
I'm glad John chimed in, because I'd wondered what the auto system would
do when it reached its max timing - close the shutter.
I'll look up the Kodak books, though I doubt I'd have them for the next
class.
Martin
-----Original Message-----
From: Chuck Norcutt [mailto:chucknorcutt@xxxxxxxxxxxxxxxx]
Sent: Monday, May 16, 2011 9:21 AM
To: Olympus Camera Discussion
Subject: Re: [OM] Long exposures with an OM2N - advice needed
I'm with Piers. Forget the meter. I just checked the specs on my
Sekonic L-358 and the much more expensive L-558 and see that they both
claim to be able to read to EV -2. That's the extreme end of their
measuring range and is roughly the illumination provided by the full
moon when high in the sky. Ignoring reciprocity failure that might give
you an exposure of 10 minutes at f/11 (or thereabouts) at ISO 100. But
then you'd also have to compensate for reciprocity which varies by film
and exposure time.
Get the Kodak books as Piers suggests because they figured out all of
this stuff 50 years ago or even much more. It's also a lot cheaper
except that you'll need a little flashlight to read the book in the
dark. Do as astronomers do and use a red light. Doesn't interfere very
much with your night vision.
Chuck Norcutt
On 5/16/2011 8:59 AM, Piers Hemy wrote:
> If it's too dark to see the exposure meter needle, Martin, I would
> suggest that it is too dark to use an exposure meter - even a backlit
digital meter!
>
> Firstly, the meter is going to want to render things as 18% grey -
> which you probably don't want; Secondly, at exposures of several
> minutes, you are going to be "hit" by reciprocity failure; Thirdly,
> with exposures of 8 minutes, 2 minutes either way is going to be
> within tolerances of any meter in practical use.
>
> I don't think you need a meter at all!
>
> Try to track down a copy of Kodak's Adventures in Existing-Light
> Photography (Publication AC-44), or a Kodak Master Photoguide - they
> have ready reckoners for such applications. I see both on Amazon,
> starting from USD0.04. Must therefore be worth at least twice my two
pennyworth!
>
> Piers
>
> -----Original Message-----
> From: Martin Walters [mailto:mwalters@xxxxxxxxxx]
> Sent: 16 May 2011 01:12
> To: Olympus Camera Discussion
> Subject: [OM] Long exposures with an OM2N - advice needed
>
> I'm taking a short course in long exposures. From the first lesson,
> it's clear that the teacher's objective really is LONG exposures -
> 8-10 mins range, it seems.
>
> The three courses are being done at night. While we'll be in an urban
> setting, I will have to provoke exposures beyond the 0M's auto
> metering limits (3 mins or so, I gather). Trouble, as I quickly found
> out, is that I find it pretty much impossible to see the metering
> needle (compounded by old eyes).
>
> Any suggestions for a work around? And, no, I don't have an OM4T
> handy, as mine is with John H for a CLA. As a last resort, I suppose
> that I could get an appropriate digital meter with a backlit screen.
> At least I'd be able to get a reading and see it!
>
> Martin
>
> --
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