metering & 18% grey

[tony]

greets all.
been getting a little more "serious" with my camera
and was hoping someone could clear up a question i have
re: metering.

NikonN65 in manual mode .. typical 75/25 centerweighted meter.

taking a picture of a BLACK chair.
(for arguments sake)...

'measurements':

a reading from the inside of my palm (dont have a grey card)
the camera/meter reads: 1/30 @ f/4.5

a reading from the back of the chair
(black fills the frame): 1.5seconds @ f/4.5

thats about 5 stops different!

why are these so far apart? where is my
mistake? which is the correct exposure?

curve ball: in AperaturePriority
the black chair reads 1/20 @ f/4.5
... why the one stop difference?

cant figure out what MatrixMetering is reading
because it INSISTS on using the flash.

any ideas?
thanks in advance.
-tony

[John O.]

>
> thats about 5 stops different!
>
> why are these so far apart? where is my
> mistake? which is the correct exposure?

You've made no mistake. If the light falling on your gray card (palm) is
the same as the light falling on the chair, then that is the correct
exposure. If you meter something solid black, or solid white for that
matter, your meter will try and make it 18% grey. That's its job.
Relax... all is well.

>
> curve ball: in AperaturePriority
> the black chair reads 1/20 @ f/4.5
> .. why the one stop difference?

Probably using a different metering pattern. And don't meter the black.

>
> cant figure out what MatrixMetering is reading
> because it INSISTS on using the flash.

If you are in an auto mode, the camera will want to use flash when the
shutter speed falls below about 1/60. Just meter the gray card.

>
> any ideas?
> thanks in advance.
> -tony
>
>
>

--
John O.
There is no slack in light attack.

[Not in my trousers]

"tony" <antoniogatta@hotmail.com> wrote in message
news:lv7Qa.23056$it4.583542@news1.tin.it...

> greets all.
> been getting a little more "serious" with my camera
> and was hoping someone could clear up a question i have
> re: metering.
>
> NikonN65 in manual mode .. typical 75/25 centerweighted meter.
>
> taking a picture of a BLACK chair.
> (for arguments sake)...
>
> 'measurements':
>
> a reading from the inside of my palm (dont have a grey card)
> the camera/meter reads: 1/30 @ f/4.5
>
> a reading from the back of the chair
> (black fills the frame): 1.5seconds @ f/4.5
>
> thats about 5 stops different!
>
> why are these so far apart? where is my
> mistake? which is the correct exposure?
>
> curve ball: in AperaturePriority
> the black chair reads 1/20 @ f/4.5
> .. why the one stop difference?
>
> cant figure out what MatrixMetering is reading
> because it INSISTS on using the flash.
>
> any ideas?
> thanks in advance.
> -tony
>

This is EXACTLY what we would expect ...
Take a look at this [url]http://www.normankoren.com/zonesystem.html[/url] I hope it
will explain it for you :-)

[Rudy Garcia]

In article <lv7Qa.23056$it4.583542@news1.tin.it>,
"tony" <antoniogatta@hotmail.com> wrote:

> greets all.
> been getting a little more "serious" with my camera
> and was hoping someone could clear up a question i have
> re: metering.
>
> NikonN65 in manual mode .. typical 75/25 centerweighted meter.
>
> taking a picture of a BLACK chair.
> (for arguments sake)...
>
> 'measurements':
>
> a reading from the inside of my palm (dont have a grey card)
> the camera/meter reads: 1/30 @ f/4.5
>
> a reading from the back of the chair
> (black fills the frame): 1.5seconds @ f/4.5
>
> thats about 5 stops different!
>
> why are these so far apart? where is my
> mistake? which is the correct exposure?
>
> curve ball: in AperaturePriority
> the black chair reads 1/20 @ f/4.5
> .. why the one stop difference?
>
> cant figure out what MatrixMetering is reading
> because it INSISTS on using the flash.
>
> any ideas?
> thanks in advance.
> -tony
>
>

Assuming all the readings are taken with the same incident light:

Your palm (if clean :-) should read 1 stop over mid-tone. Therefore the
more correct exposure based on your palm should be 1 stop more than the
meter, or 1/15 @ f/4.5 . This is the reading you would have obtained
with a grey card if you had one at the time.

Why the black chair reads what it does? I don't know. I would have
expected someting more like 2 or 3 stops from 1/15 @ f/4.5 .

--
Rudy Garcia

[Paul Brecht]

Here's some info about this:

[url]http://www.bythom.com/graycards.htm[/url]

Paul
/////////////////

"Norman Worth" <nworth@earthlink.net> wrote in message
news:4kkQa.99468$Io.8549956@newsread2.prod.itd.ear thlink.net...

> Meters are typically calibrated to give correct exposure at 12 percent
> reflectance. An 18 percent gray card (Zone V, for those who use the zone
> system) will give the right exposure with a little margin when metered.
> Your hand (Zone VI) will be about one stop brighter - 1 stop less

exposure.

> The black chair (Zone I or II, depending on the circumstances) will ask

for

> three or four stops more exposure. The meter is indicating the exposure
> assuming 12 percent reflectance. Your hand is reflecting more than 12
> percent, the chair less.
>
> The Nikon cameras have truly marvelous exposure meters. For general

picture

> taking, they are almost foolproof. They even compensate for most uneven
> lighting situations. But they can be fooled by truly unusual subjects,

such

> as very light or dark scenes that you want to show as truly light or dark.
> In these cases, you can use the exposure compensation feature on the

camera

> and bracketing to get the right exposure.
>
> "tony" <antoniogatta@hotmail.com> wrote in message
> news:lv7Qa.23056$it4.583542@news1.tin.it...

> > greets all.
> > been getting a little more "serious" with my camera
> > and was hoping someone could clear up a question i have
> > re: metering.
> >
> > NikonN65 in manual mode .. typical 75/25 centerweighted meter.
> >
> > taking a picture of a BLACK chair.
> > (for arguments sake)...
> >
> > 'measurements':
> >
> > a reading from the inside of my palm (dont have a grey card)
> > the camera/meter reads: 1/30 @ f/4.5
> >
> > a reading from the back of the chair
> > (black fills the frame): 1.5seconds @ f/4.5
> >
> > thats about 5 stops different!
> >
> > why are these so far apart? where is my
> > mistake? which is the correct exposure?
> >
> > curve ball: in AperaturePriority
> > the black chair reads 1/20 @ f/4.5
> > .. why the one stop difference?
> >
> > cant figure out what MatrixMetering is reading
> > because it INSISTS on using the flash.
> >
> > any ideas?
> > thanks in advance.
> > -tony
> >
> >
> >

>
>

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