I've been checking out the metering on my earlier-style model (the one with the prism meter).

The red/green indicators seem to jump with a slight shift in a scene.
Unless I need to try newer batteries, I'm wondering if it's not metering closer to the center (or some other spot) of the frame.


I will probably be using my Gossen meter and Hassie finder anyway, but I'd like to see how the built-in meter and prism work out too.

The newer, meter-in-camera models are said to have improved metering - any comments?

lattie_smart wrote:

> I've been checking out the metering on my earlier-style
> model (the one with the prism meter).
>
> The red/green indicators seem to jump with a slight shift
> in a scene. Unless I need to try newer batteries, I'm
> wondering if it's not metering closer to the center (or
> some other spot) of the frame.
>
>
> I will probably be using my Gossen meter and Hassie
> finder anyway, but I'd like to see how the built-in meter
> and prism work out too.
>
> The newer, meter-in-camera models are said to have
> improved metering - any comments?

Let's backup. In all models of the TL120-1 I have ever seen,
the meter is in the camera body. The only difference between
the models is where and how the light to be metered is gathered.

See my notes on this at:
http://stereo.thurstons.us/updates.htm

The early versions of the camera had a photo cell in the
prism which was electrically connected to the body at the
front edge of the ground glass. There may be two or three
contacts (depending on the model), but they are _electrical_
contacts.

The later version of the camera has the photo cell in the
body of the camera and there is an _optical_ connection
between the prism and the body. There is a bundle of
fiber-optics in the prism sampling the light and
transferring that sample to the photocell on the body. I
don't know how the fibers are arranged on the prism. It is
_possible_ that the fibers are distributed to provide a
"center weighted" metering, but I really doubt it.

In all cases, the in-camera meter is fully, totally,
absolutely, 100%, entirely dependent on the prism finder.
The meter in the TL120 WILL NOT WORK without the finder.
Anyone who suggests otherwise (as may be seen in some sales
literature) is mistaken.

Further, it must be the correct style prism for the camera.
This means that I can not swap the 90-degree and 45-degree
prisms from my two cameras and expect the meter to work. My
90-degree prism has electrical connections. My 45-degree
prism has an optical connection.

All that said, I use the built-in meter for hand-held shots
with my TL120-1. If I'm going to the trouble of setting up a
tripod, I'm also going to the trouble to use my hand-held
light meter.

--
John Thurston
Juneau Alaska
http://stereo.thurstons.us

OK, I'm right there with you on the tripod and hand meter scenario!

I guess I misunderstood the reviewed differences between the two meter systems - with the -cell only- being in my (older) prism system.

Maybe because of the simple LED system, the red-to-green shifting is like my old K-1000 analog meter needle bouncing up and down just a bit - while still in an optimal, middle range. But, at least in this TL-120's prismfinder, the green signal has a very small tolerance for the slightest shift or re-framing of outdoor and indoor scenes. It's like it's not taking in the whole frame's EV, just some small, sensitive portion of it. Or it only shows correct exposure when you're within 1/10th of an EV? ;-)

I'm just wondering if anyone else notices this skittishness on either models' metering?

The check works OK on the batteries, but if this all goes away after I change them, I will have my answer (and egg on my face!)

--- In MF3D-group@yahoogroups.com, John Thurston wrote:
>
> lattie_smart wrote:
> > I've been checking out the metering on my earlier-style
> > model (the one with the prism meter).
> >
> > The red/green indicators seem to jump with a slight shift
> > in a scene. Unless I need to try newer batteries, I'm
> > wondering if it's not metering closer to the center (or
> > some other spot) of the frame.
> >
> >
> > I will probably be using my Gossen meter and Hassie
> > finder anyway, but I'd like to see how the built-in meter
> > and prism work out too.
> >
> > The newer, meter-in-camera models are said to have
> > improved metering - any comments?
>
> Let's backup. In all models of the TL120-1 I have ever seen,
> the meter is in the camera body. The only difference between
> the models is where and how the light to be metered is gathered.
>
> See my notes on this at:
> http://stereo.thurstons.us/updates.htm
>
> The early versions of the camera had a photo cell in the
> prism which was electrically connected to the body at the
> front edge of the ground glass. There may be two or three
> contacts (depending on the model), but they are _electrical_
> contacts.
>
> The later version of the camera has the photo cell in the
> body of the camera and there is an _optical_ connection
> between the prism and the body. There is a bundle of
> fiber-optics in the prism sampling the light and
> transferring that sample to the photocell on the body. I
> don't know how the fibers are arranged on the prism. It is
> _possible_ that the fibers are distributed to provide a
> "center weighted" metering, but I really doubt it.
>
> In all cases, the in-camera meter is fully, totally,
> absolutely, 100%, entirely dependent on the prism finder.
> The meter in the TL120 WILL NOT WORK without the finder.
> Anyone who suggests otherwise (as may be seen in some sales
> literature) is mistaken.
>
> Further, it must be the correct style prism for the camera.
> This means that I can not swap the 90-degree and 45-degree
> prisms from my two cameras and expect the meter to work. My
> 90-degree prism has electrical connections. My 45-degree
> prism has an optical connection.
>
> All that said, I use the built-in meter for hand-held shots
> with my TL120-1. If I'm going to the trouble of setting up a
> tripod, I'm also going to the trouble to use my hand-held
> light meter.
>
> --
> John Thurston
> Juneau Alaska
> http://stereo.thurstons.us
>