Skan exposure meter

Hello,

I found a Skan exposure meter (G-M Laboratories, Chicago). I wanted to possibly use this for a lightmeter, but I know its very old (like 1940s).

Does anyone know how to use this thing, or know where I can find out how?

Thanks

--

'When a task cannot be partitioned because of sequential constraints, the application of more effort has no effect on the schedule. The bearing of a child takes nine months, no matter how many women are assigned.' - Frederick P. Brooks Jr.
-------------
http://flickr.com/photos/majorconfusion

MajorConfusion said:

Hello,

I found a Skan exposure meter (G-M Laboratories, Chicago). I wanted
to possibly use this for a lightmeter, but I know its very old (like
1940s).

Click to expand...

If this is the device you have....

http://cgi.ebay.com/40 'S-%2F-50'S-SKAN-LIGHT-METER.-LOW-PRICE-NO-RESERVE_W0QQitemZ300287386845QQcmdZViewItemQQimsxZ20090117?IMSfp=TL090117115001r27410

... then, assuming it is working, I cannot think of anything it can do that cannot be done 50 times better by the meter built into a modern camera.

MajorConfusion said:

Does anyone know how to use this thing, or know where I can find out
how?

Click to expand...

The picture doesn't show any outward signs of this meter being adjustable either for shutter speed, or film speed ('sensitivity', now referred to as ISO).

All we can see is a needle swinging against a scale with some aperture values on it. This suggests the meter was designed for a very limited kind of use, even when it was new.

My guess is it was probably sold as a companion piece to some camera that itself was restricted to ONE shutter speed only, as many simple film cameras were..... with that camera similarly having only ONE film recommended for use in it, which also happened quite often in simple cameras until fairly recently.

In use the meter would have been pointed at an average tone in the subject, with the camera's aperture then set to the value indicated.

This operation would have been restricted to good light (daylight only) as the selenium cell that powers it has VERY low sensitivity compared with what we are used to today.... but then the intended camera itself was likely capable of shooting only in daylight because of its (believed) single speed.

Q: Is the device worth learning to use with modern digital camera, say, by experimenting and formulating a table of comparative values?

A: Definitely not, unless you enjoy doing things the hard way out of sheer cussedness. This is not to say that the exercise might not be an interesting intellectual challenge in its own right, but it won't do a darn thing to help you meter your shots and improve your photography.

Conclusion:

It is a novel item from a previous era of photography, and, if you have the house room to keep it, can act as a reminder of how stuff is "the latest thing" for a relatively short period of time!

Now, if you want advice on a suitable modern separate meter, because you are going to shoot with studio flash, for instance, then do post a question in this forum. There will be lots of answers, I'm sure.
--
Regards,
Baz

Also, the selenium degrades over the period, so the sensitivity may be unexact.

(OT: Baz, is the snow still lying knee-high? ;-)

--
cheers, Peter

Germany

Peter Berressem said:

Also, the selenium degrades over the period, so the sensitivity may
be unexact.

(OT: Baz, is the snow still lying knee-high? ;-)

Click to expand...

Hey! We certainly got more snow than Britain has been used to in recent years....

Here is a report from Burpham, near Guildford, Surrey.

Snow was 14" (36cm) deep outside my door a couple of days ago, which was as much as fell anywhere in UK on Sunday/Monday night.

I cleared a way out to the road yesterday afternoon, so my wife could get to work today....

.... but now the only real obstructions to traffic locally are frozen heaps in the sides of roads cluttered up with parked cars that have not yet been moved.

We are having to drive carefully on minor roads, because the slush is freezing again tonight, though, with fresh falls expected, they say... (shrugs).

Hmmm.... Funny how it doesn't seem so much fun when you are 60 instead of 6!

Thanks for taking an interest. Have you had snow falls from the same weather system?
--
Regards,
Baz

Luckily we were just spared from this low-pressure area (reaching from south of France to Scotland, IIRC). We had our similar share some weeks ago, though not as bad as actually the south-east of the US is hit.

News says that another deep freeze period for Europe is to be expected in the second half of February :-(
Take good care!

--
cheers, Peter

Germany

It has a fixed wheel with f-stops and a movable wheel with shutter speeds on the back.

Barrie Davis said:

MajorConfusion said:

Hello,

I found a Skan exposure meter (G-M Laboratories, Chicago). I wanted
to possibly use this for a lightmeter, but I know its very old (like
1940s).

Click to expand...

If this is the device you have....

http://cgi.ebay.com/40 'S-%2F-50'S-SKAN-LIGHT-METER.-LOW-PRICE-NO-RESERVE_W0QQitemZ300287386845QQcmdZViewItemQQimsxZ20090117?IMSfp=TL090117115001r27410

... then, assuming it is working, I cannot think of anything it can
do that cannot be done 50 times better by the meter built into a
modern camera.

Barrie Davis said:

Does anyone know how to use this thing, or know where I can find out
how?

Click to expand...

The picture doesn't show any outward signs of this meter being
adjustable either for shutter speed, or film speed ('sensitivity',
now referred to as ISO).

All we can see is a needle swinging against a scale with some
aperture values on it. This suggests the meter was designed for a
very limited kind of use, even when it was new.

My guess is it was probably sold as a companion piece to some camera
that itself was restricted to ONE shutter speed only, as many simple
film cameras were..... with that camera similarly having only ONE
film recommended for use in it, which also happened quite often in
simple cameras until fairly recently.

In use the meter would have been pointed at an average tone in the
subject, with the camera's aperture then set to the value indicated.

This operation would have been restricted to good light (daylight
only) as the selenium cell that powers it has VERY low sensitivity
compared with what we are used to today.... but then the intended
camera itself was likely capable of shooting only in daylight because
of its (believed) single speed.

Q: Is the device worth learning to use with modern digital camera,
say, by experimenting and formulating a table of comparative values?

A: Definitely not, unless you enjoy doing things the hard way out of
sheer cussedness. This is not to say that the exercise might not be
an interesting intellectual challenge in its own right, but it won't
do a darn thing to help you meter your shots and improve your
photography.

Conclusion:

It is a novel item from a previous era of photography, and, if you
have the house room to keep it, can act as a reminder of how stuff is
"the latest thing" for a relatively short period of time!

Now, if you want advice on a suitable modern separate meter, because
you are going to shoot with studio flash, for instance, then do post
a question in this forum. There will be lots of answers, I'm sure.
--
Regards,
Baz

Click to expand...

--

'When a task cannot be partitioned because of sequential constraints, the application of more effort has no effect on the schedule. The bearing of a child takes nine months, no matter how many women are assigned.' - Frederick P. Brooks Jr.
-------------
http://flickr.com/photos/majorconfusion

MajorConfusion said:

It has a fixed wheel with f-stops and a movable wheel with shutter
speeds on the back.

Click to expand...

So maybe it isn't quite so limited as at first it appears.

Can you post a picture, so we can see get better idea of the modus operandi?

(Still pretty much a curiosity rather than a working tool, though.)
--
Regards,
Baz

BTW, I saw an add for this in a 1947 Popular Mechanics magazine for $14.99. In 2007 money that like $150!







--

'When a task cannot be partitioned because of sequential constraints, the application of more effort has no effect on the schedule. The bearing of a child takes nine months, no matter how many women are assigned.' - Frederick P. Brooks Jr.
-------------
http://flickr.com/photos/majorconfusion

MajorConfusion said:

BTW, I saw an add for this in a 1947 Popular Mechanics magazine for
$14.99. In 2007 money that like $150!

Click to expand...

Hmmm... still a good deal less than a good modern flashmeter.
(BTW it is now 2009!)

MajorConfusion said:

Click to expand...

Thanks for the pictures! Pretty good.

Now that we can see all its features, and very clearly, the meter is revealed as an early version of the standard style of selenium meter that was made and used over a 60 year period, until quite recently in fact....

... which means it isn't "cut down" at all, despite my earlier assumptions. Also, I can see that the needle scale is scaled for light strength, not 'apertures' at all. Indeed, all the features of a perfectly usable meter are on this one.

Yes, it is a selenium type, using a photo-voltaic cell that needs no battery. As stated, selenium cells are not particularly sensitive... but in good light, and assuming that the cell hasn't failed, there is no reason why this meter couldn't be used even to-day. It just won't do the job quite so easily as the super sensitive cross-coupled meter built in to your camera and reading through the lens.

To someone who's familiar with this kind of meter it's all straightforward. The dials are all nicely labelled, and the mode of operation is actually printed on the thing!

Printed in in RED
-- Meter needle and its scale indicating "Light Values" (Light intensity)

-- "Exposure Index" for different film speeds (now referred to as ISO sensitivity).

Printed in BLACK
-- "Shutter speed" scale in fractions of seconds and whole seconds, resp.
-- "Aperture" scale, in whole and 1/2 stop increments.

How to use....

1) The meter is pointed at a suitable mid tone grey in the subject, or a substitute grey card held in the same light as the subject, and the "Light Value" read from the scale and noted.

2) The meter is then turned over, and the noted "Light Value" is then simply aligned with the "Exposure Index" for the film in use.

3) The act of aligning the "Light Value" with the "Exposure Index" similarly aligns a whole series of "shutter speeds" against corresponding f/numbers ("apertures"), anyone of which combination pairs will yield a correct exposure.

4) From that range of shutter/aperture combinations currently available the photographer simply chooses the one most suitable for his subject and how he wants to render it.....

.... in effect he may choose --Shutter Priority Mode-- if freezing action, say,

.... or he may use --Aperture Priority Mode-- if controlling DoF is his main concern.

What we do not know about your meter is if the cell is working sufficiently to swing the needle up to the correct Light Values.

And we don't know for sure whether the Exposure Index values match, or can be converted to, modern ISO ratings. Although this is an early meter they just may be ASA film speeds which are directly usable as ISO without change.

It's not hard to reverse engineer the sensitivity setting, and come up with a conversion if necessary, because we know the correct exposure in certain standard daylight conditions.....

.. namely the "Sunny 16" rule, which means that....

-- setting f/16 alongside 1/100th second on the black scales
-- and pointing the (properly working) meter at a grey card in Clear Sunshine
-- should yield the Light Value reading against the EQUIVALENT of 100 ISO....

... whatever that is on your meter. Naturally, it would be good if it actually aligned with 100, of course, but it may not. Any difference would be consistent across the scale, however (if the meter is working correctly) and would allow you to build a conversion scale.
----------------------------------------------------------------------

Even though the meter isn't so hard up for scales as at first I thought, the fact remains that your camera's meter is the appropriate tool to use today, even if it is an interesting exercise to investigate how this one worked back in its own time.

Thank you for showing us your little trophy. It was nice to see an instrument from 10 years before I began taking photographs seriously.
--
Regards,
Baz