Leudi Meter

[ernesto]

I have just found an old LEUDI extinction meter

It is a very interesting device. No battery, no complex mechanisms, just by eye! I will give it a try.
Anyway, any practical feedback from previous users will be greatly appreciated!

Yours
Ernesto

PS.: Here the definition in Wikipedia:
The earliest[when?] type of light meters were called extinction meters and contained a numbered or lettered row of neutral density filters of increasing density. The photographer would position the meter in front of his subject and note the filter with the greatest density that still allowed incident light to pass through. The letter or number corresponding to the filter was used as an index into a chart of appropriate aperture and shutter speed combinations for a given film speed. Extinction meters suffered from the problem that they depended on the light sensitivity of the human eye (which can vary from person to person) and subjective interpretation.
From: https://en.wikipedia.org/wiki/Light_meter

 

[sevo]

Extinction meters work very well in "sunny 16" conditions - but as they are not independent of eye accommodation, they are useless in low light. That is, all around they are no better than a table of time and weather conditions. Outside sunlight, the entire concept of visual light metering will only work in meters that provide a artificial reference (like the SEI)...

 

[Roger Hicks]

They can be surprisingly useful if you hold them to the eye and take a quick reading (2-3 seconds). Take any longer and the pupil dilates and makes them useless.

Cheers,

R.

 

[ernesto]

Interesting...
Thanks for your feedback.

I have tried to compare the readings in the LEUDI meter with my Sony camera, and found that it works perfect in the following tests:

1) Cloudy and rainy exterior daylight. I found you have to "focus" in a neutral gray object to take measurements. If you focus on a bright object (which was my instintive reaction) the exposure will be underexposed.
2) Interiors with white walls with natural or artificial light. It worked perfectly in the same way. I tried bright interiors and very dim light interiors and got very acceptable readings.
3) Sunlight Exterior (even in bright cloudy environment) It seems to work perfect too.

Couldn`t test the Interior with dark walls, nor Sunny in the beach or the snow, yet.

During the first test I have got bad results, and I found that it is very important that you (the photographer) are in the same lighting condition as the subject. This has to do probably with the iris adjustment which could affect the readings. In my first test I was inside house looking outside in a rainy day. Those were too bad readings. But then I went out to the porche and waited for my eyes to acomodate to the lighting condition and then I have got good results. It is needed certain time to accomodate your eyes to the lighting condition. It is also very important to identify the proper lighting condition. I will do some more tests in order to understand the possible limits. For instance I failed many times with the last lighting condition (blue square) which is the lowest lighting condition, and it took me many hours to realize it says:

Interiors with dark light or with low artificial ilumination.

I have no dark lights in my home... but tried very low artificial lighting, but it didn´t worked...
Perhaps the dark wall are determinant, and at the time the LEUDI meter was created the meaning of LOW ARTIFICIAL ILLUMINATION could be very diferent from the modern concept of LOW ARTIFICIAL ILLUMINATION.
Anyway I will try to find out a dark walls room for my next tests.

Ernesto

 

[ernesto]

I have just found that there are too many diferent models of LEUDI meters, which difers in the standard light scales.

Here I have found a complete explanation of them, and their equivalents.

http://www.jollinger.com/photo/meters/other/speed_table.html

https://en.wikipedia.org/wiki/Film_speed

My LEUDI seems to be made arround 1934 before DIN / ASA / ISO standards, so it took me some time to identify that they were written in the old European Sheiner units.