[pure-silver] Re: Metering 135 vs 120

I use a Minolta IVF I believe and it has an adjustment buried in the back so a 
tech could make the adjustments IIRC.

Mine can be either a reflective or incident light meter, but to be a reflective 
meter it requires an additional attachment.  Unless you are using the extra 
attachment that makes it a spot meter, then its a incident meter and that 
introduces a number of issues.

Let me suggest a couple of tests.  Richard please chime in here if you see some 
things that would help.

First is if you can do it on a bright sunny day it would be best.  Why?  With 
that bright sunny day you have the sunny 16 rule to keep you close.  If you 
have a big difference between the meters, on a bright sunny day the most likely 
one to be reading properly is the one closest to the sunny 16.  Without that 
all you have is two different meter readings.

Second compare the readings with the in external meter and the reading of the 
in camera with the camera pointed at a gray card with the full frame covered by 
the card.  If the meters readings are close, it likely isn't the meters unless 
there is a drastic difference between what they read and the sunny 16.  If you 
find a problem, Id probably just take them both to the shop.  At that point the 
tech can tell you not only that they are off and by how much.  If they can't 
correct the problem with an in camera adjustment, you can compensate for the 
difference yourself.  

I ran into this a few years ago and found another way to foul up. I had been 
doing a lot of 35 mm with in camera metering, then moved to one that had an 
external meter.  I stuck a filter on the lens and forgot to compensate for the 
filter factor.  Then it took me a while to figure out why I had thin negatives. 
 Very very unlikely in your particular situation, but something to check if 
others happen to run into this type of thing somewhere down the line.

One other possibility is that the problem isn't in the metering, but in the 
shutter.  A slow shutter is more common, in that time and use tends to make 
springs less effective and junk ect and all sorts of things that happen via 
normal use can slow the shutter down, particularly at slow shutter speeds.  I 
have heard of a shutter getting hung up at a higher speed than the dial would 
show.  It would let you move the dial to 1/125th of a second, but the mechanics 
were stuck on 1/250th.  If the shutter is electronic it would be highly 
unlikely.  I guess it might still drag, but the electronics eliminate a lot of 
mechanical things that can go wrong.

My old 4x5 shutter is about a stop slow at slower speeds.  As the speed 
increase the drag drops off so there really isn't much of an effect the way I 
play with the camera.  To fix it would cost way more than the camera is worth.  
I just adapt.

Now if you find that all that checks out, then Id use what ever processing you 
need to get what you are looking for in a negative.

--- On Tue, 8/26/08, Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:

> From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
> Subject: [pure-silver] Re: Metering 135 vs 120
> To: pure-silver@xxxxxxxxxxxxx
> Date: Tuesday, August 26, 2008, 5:34 PM
> ----- Original Message ----- 
> From: <eroustom@xxxxxxxxxxx>
> To: <pure-silver@xxxxxxxxxxxxx>
> Sent: Tuesday, August 26, 2008 3:14 PM
> Subject: [pure-silver] Metering 135 vs 120
> 
> 
> > > There is for me.  I'm assuming it's a
> difference in 
> > > metering.  My 35s
> >> have built in meters while I use a Minolta IVF for
> the 
> >> mf.  The
> >> exposures seem to be very different so I always
> have to 
> >> add
> >> developing time for my 120 film.  I shoot TMax
> (finishing 
> >> off some
> >> old film) and TriX.
> >
> > That's an interesting problem. Why not chase down
> the 
> > metering issue, and leave a variable out of
> processing?
> >
> > Your minolta is an ambient light meter (I think), and
> your 
> > camera's TTL meter is an incident meter?
> >
> > I've noticed some situations that have given me
> readings 
> > two stops off from each other when using my handheld
> meter 
> > against the TTL in my Canon bodies. But I assume
> it's how 
> > I'm using the meter(s), so I work to find the same
> 
> > reading, or try to reason out why that's
> happening. 
> > Sometimes the lens (I use a 24, a 35, a 50, or 100)
> brings 
> > in less or more light to the TTL meter at the back -
> or so 
> > it seems - or they average differently, whereas the 
> > handheld meter has no lens in front of it.
> >
> > But an exposure value for Zone V, or 18% gray, for a a
> 
> > given ISO should be the same from meter to meter, no?
> >
> > Can anyone more experienced chime in on this?
> >
> > Elias
> >
> >
>     Some meters seem to be calibrated for 12% mid gray. In 
> general, however, a reflected light meter should read the 
> same from an evenly illuminated 18% gray card that fills
> its 
> field of view as an incident light meter reading the 
> illumination. There are some variations on this, for 
> instance, my ancient Weston Master II does not agree with 
> either my Luna Pro or with a Sekonic Studio Deluxe (Norwood
> 
> pattern) meter. This is with the correct equivalent Weston 
> speed set. I've come to the conclusion that either
> Weston 
> included a fudge factor in its speeds or that the
> calculator 
> is set up for some other reflectance for the pointer value 
> than 18%. In any case, I get the identical readings when
> the 
> Weston speed is set for about half of the speed translated 
> from ISO speeds. I have a second Weston meter of a
> different 
> type which shares this characteristic. My old GE meter 
> agrees with the two more modern meters. To be clear, the 
> Luna Pro and Sekonic agree exactly for both incident and 
> reflected light.
> 
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx 
> 
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