Re: PHOTO-3D digest 1602

[P3D <dlevy@xxxxxxxxxx>]

>Date: Fri, 11 Oct 1996 11:15:36 -0400
>From: P3D  <GCCampos@xxxxxxx>
>To: photo-3d@xxxxxxxxxxxxxxx
>Subject: Light Meters/Zone V
>Message-ID: <961011111536_1111619921@xxxxxxxxxxxxxxxxxxxx>
>
>[This message may have contained graphics created by a Magic Cap device on
>America Online.]
>
>I use to think that If I took the time to point my inherited General Electric
>light meter at something and then set my camera to whatever it said, my
>pictures would turn out.  Not so (save for the wonderful latitude of print
>film).  
>First of all, as with many older light meters, the ASA setting on the meter
>is not the same as the ASA that film is rated at today.   For old GE meters,
> ASA 100 film corresponds to ASA 125  on the meter,  and 400 film is 500 on
>the meter.  Secondly,  If I point the meter at an object and set my camera to
>whatever it tells me to, that object will end up having a little darker shade
>of gray than a plastic film case cap (Whether the original object was very
>dark or very light).  
>In other words, all the light meter can tell me is, "set your camera to this
>setting if you want the object you're pointing me at to look medium gray, the
>same as an %18 gray card, zone five."  
>So now I know, that if I point my light meter at a bright snow wall and want
>it to look bright white, about zone 8.5,  in my picture, I have to adjust my
>camera by 3.5 stops (from f/16 to f/5, or from 1/500 of a second to 1/50)
>from what the meter says.  Likewise, if I point my meter closely at a dark
>brown tree trunk, and want it to look the same, I'd have to adjust my camera
>about two stops the other way.
>
>Please forgive me if this is wasted space, but I would have saved lots of
>film had I understood this years ago.
>
>Please correct me if I've made errors. 
>
>Grant Campos
>
>PS. For an excellent interactive online ZONE system lessons check out 
>http://www.cicada.com/pub/photo/zs/
>
>Actually, this is not quite accurate. All GE selenium meters with the
prefix PR before the model # were in ASA which is the current ISO standard.
GE meters, though built like a tank are more likely to go out of calibration
than Weston meters. Simply zero adjusting the needle does not calibrate it.
Also, selenium meters wear out in a similar manner that a electron tube does
where battery meters tend to go out like semiconductors. By adjusting the
ASA as described, you may be compensating for the dying selenium cell.
Quality light metric can renew Weston meters. I don't know about GE meters.
The GE I had worked well and had stayed calibrated since I acquired it new.
About a year ago I gave it to a friend who used a Minolta something or
other. Last time I checked, he was using the GE for almost all work.


The discussion re: the measuring of 18% gray for everything is correct. It
is a starting point. If you use the meter as a averaging reflective meter,
there is an assumption that the overall tone is 18% gray. This works in move
than many instances to give an acceptable neg. If you have the incident
attachment, you could use it as such, but should end up with the same
reading. (that's correct. take a reflective reading off an 18% gray card and
an incident reading and they should be the same) Here's the play. Many times
there is need to adjust this reading because of the contrast range of the
film being used AND the subject. The GE, because of its construction can be
set to use the zone system. Rather than go into it, I'd suggest that you
pick up one of many books written about it. The power of the meter is in its
use in allowing the photographer to place the tones. This coupled with
processing will allow expansion or contraction of the contrast range with
the critical tone being placed where it was envisioned.

To those who use the sunny16 rule, this appears complex. While the sunny16
rule is a good guide to obtain the ev of what you want to photograph, the
meter w/ or w/o the use of the zone system allows more control. But this
requires understanding and practice and may not be necessary for all
shooters based upon the their objectives and preferences. 
>
Brian Levy, J.D.
Toronto, Ont.
dlevy@xxxxxxxxxx


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End of PHOTO-3D Digest 1604
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