[ismaelg]

Hello,

Since the inception of photography almost 200 years ago, understanding and mastering light has always been and will always be the fundamental base of photography. Geez, I should be a philosopher!

Technology has always been advancing in the area of exposure estimation and automation. From early Sunny 16 tables to today's advanced multimode predictive super duper nuclear powered multidimensional and time traveling metering, getting the exposure right is the goal. Light metering has come a long way.
One of the earliest types of light meters was the extinction meter in the late 19th century. There were several variations and types but essentially, it consists of an array of calibrated ND filters of different values. The photographer will look at the scene thru it and determine which value still allows light thru and that will be the basis for an exposure calculator to suggest appropriate exposure combinations.

Let me show you an example with this Argus A2B, equipped with an extinction meter/calculator. Argus introduced this type of extinction meter in their cameras in 1939 on the A2B and A2F models.
(You can read more about this camera in this link: 1948 Argus A2B: Entry level 35mm popularization camera - PentaxForums.com)



First of all, this meter is calibrated in Weston sensitivity, Not ASA/ISO
The conversion is:

ASA - Weston
15 --- 12
25 --- 20
50 --- 40
100 ---72

ASA 100 was considered fast in its day

Steps for calculating the exposure:

1. Point the meter to the scene and determine where the light falls off. Dimmest window still letting light go thru

2. Move the slider to match that location



3. Set the sensitivity



4. Set the conditions: Bright, Average, Cloudy, Interior lit room.
Make sure both sliders move together to ensure proper sensitivity. If not, adjust accordingly.


5. Take a reading from the calculator
Examples:




So, next time you complain about the meter in your DSLR, remember those before you that had to use these.

Hope you like this.

Thanks,
Ismael

[kypfer]

Thanks for sharing
I was aware of extinction meters but never had the opportunity to try one.
At least you don't have to worry about the battery going flat

[Sam_I_am]

Glad to know what that thingy majig is called and how to use it.

[ramseybuckeye]

So . . somebody has to ask . . .Is the extinction meter officially extinct? Or just endangered

[pacerr]

The abacus of light meters - with a nod to Sunny Sixteen.

[kypfer]

So . . somebody has to ask . . .Is the extinction meter officially extinct? Or just endangered

Technically, it's probably a relict population … managing to just about maintain numbers but with little likelihood of regaining it's former status

[Lord Lucan]

My father had an extinction meter, but it was not as complex as that one and not attached to a camera. I guess he bought it around the mid-1950's and I remember looking through it. It was about the size and shape of a Weston type meter. You simply saw a row of numbers which were progressively darker, and you noted the darkest one that you could read. AFAIR, you then consulted a table on the body of the thing which recommended an exposure. I can't remember the table but I guess showed aperture/shutter speed combinations, perhaps for 50 ASA film, and you could extrapolate for anything else.

[TwoUptons]

My father had an extinction meter, but it was not as complex as that one and not attached to a camera. I guess he bought it around the mid-1950's and I remember looking through it. It was about the size and shape of a Weston type meter. You simply saw a row of numbers which were progressively darker, and you noted the darkest one that you could read. AFAIR, you then consulted a table on the body of the thing which recommended an exposure. I can't remember the table but I guess showed aperture/shutter speed combinations, perhaps for 50 ASA film, and you could extrapolate for anything else.

I have one of those in box somewhere... they're really cool... if not terribly more useful than Sunny-16 and its modifications...
...and I found the box...

Here it is from the outside... sitting on the lens cap of a DA Limited 20-40 for scale...


And with a bright light and a terrible focus stack to let you see the f-stops...


I seem to recall one that had the numbers on a roll (one set at a time, turn the knob to get another set of numbers) so you could use them in different conditions or for different films... I don't recall the details.

-Eric

[BigMackCam]

Very cool, Ismael - thanks for the interesting info. Now I want an A2B just so I can play with the extinction meter