[pure-silver] Re: Metering 135 vs 120

My thinking's good as a drunks too. I didn't think of the meter thing, but I did think of the air in the tires. Guess that's cause I wasn't in the truck! 


On Aug 27, 2008, at 2:37 PM, Mark Blackwell wrote:
Janet you didn't think of it because it was simple and often the simple things are the easiest to overlook.
Reminds me of an old story my dad told me when we crossed a low bridge years and years ago. He was stuck behind this truck that was just a little bit too tall to fit under the bridge. It was less than an inch too high, but an inch was as good as a mile.
Thing is there was no where for the truck to turn around. It was stuck and even if it could turn around the alternate route would have added many many hours to the trip. People caught in the jam up started coming up with ideas to get the truck down just that little bit. It took a drunk that happened to be passing by to come up with the answer. My dad was laughing when the guy staggered up to the truck, looked up at the bridge, swung around to look at the side of the truck hanging on to the front fender to keep from falling, then said "Let some air out of the tires and it will go right through."
They did, and it worked. The trucker gave the drunk another half pint of booze and everyone was happy. Just a few miles down the road, a stop at a gas station and the air was put back in the tires. It was so simple it was easy to overlook. In photography I have found the best solutions are really often the simple ones, but they are often hard to catch.
Now I guess that makes me the drunk in this case, but its too bad you can't mail booze. Oh well. Let us know if you find some major differences. You have my curiosity up now. 


--- On Wed, 8/27/08, Janet Cull <jcull@xxxxxxxxxxxxx> wrote:


From: Janet Cull <jcull@xxxxxxxxxxxxx>
Subject: [pure-silver] Re: Metering 135 vs 120
To: pure-silver@xxxxxxxxxxxxx
Date: Wednesday, August 27, 2008, 12:45 PM
Mark,  Thanks for taking the time to answer.  I will try the
two
meters, testing one against the other.  I don't know
why I didn't
think of that.  I did have the shutter tested on both my
Zeiss lenses
and they're fine.  Thanks again.

Janet


On Aug 26, 2008, at 10:48 PM, Mark Blackwell wrote:


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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