Olympus-OM
[Top] [All Lists]

[OM] Re: Summer shots and two questions

Subject: [OM] Re: Summer shots and two questions
From: Moose <olymoose@xxxxxxxxx>
Date: Thu, 28 Jun 2007 02:38:36 -0700
priit@xxxxxxxxx wrote:
> On Wed, 27 Jun 2007, Lukasz Grabun wrote:
>   
>> Would someone enlighten me what is wrong with my thinking and why did
>> the camera metered the light the way it did?
>>     
>
> I tend to somewhat disagree with what has been said before. Intuitively it 
> seems to me that your thinking was correct and that the center weighted 
> meter should have caused underexposure at +/- 0 with the way you framed 
> #5. Of course this is assuming the ratio of sky and ground is the same in 
> all the bracketed shots.
>   
Lukasz said that these were all metered in Auto Mode because there is 
something wrong with manual on his camera. As you know, these are two 
completely separate metering systems. What may not be obvious is that 
the Auto OTF-TTL metering is full frame average, not center weighted. 
Manual and the in-viewfinder indications for Auto are center weighted, 
but not the actual Auto exposure itself.

Early OM-2 bodies were vertically center weighted, but the curtain 
pattern was changed and remained that way for the 2n. 
http://brashear.phys.appstate.edu/lhawkins/photo/om2-curtains.shtml

Oly was very coy about this, as center-weighted metering was an initial 
feature of the OM-2 and the viewfinder metering remained that way. The 
OM-2n manual says:

"Automatic exposure control: Aperture-preferred automatic exposure 
control electronic shutter type. TTL Direct (off the film) Light 
Measuring System.:

"Manual exposure:, TTL type. Measuring system: Full aperture center 
weighted metering."

I'm not sure it makes much difference with this rather symmetrically lit 
subject, but center weighted metering is not in play here.

Looking at the image in PS, the mean luminosity of the whole image is 
146 and that of an oval roughly proportioned by eye to the proportions 
of the frame and covering maybe 20% of the whole image area has a mean 
of 145. Cropping the image to the central portion also gives about the 
same mean luminosity, so center weighting probably wouldn't be an isue 
an issue here anyway.

Moose

==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz