In article ,
Alfred Molon wrote:

In article , android says...

Won it on an auction last week. 40 years old and work just fine! :-))
https://dl.dropboxusercontent.com/s/.../PSX_20170416_
094208.jpg

I have never seen a thing like that, but perhaps it is something with
which you measure the light intensity. Is this correct?

Yes!

The other question is, why would you need such a device, when every
digital camera nowadays will readily tell you if the image is over- or
underexposed and will show a nice histogram, zebra stripes etc.

Nice to have. Very nice to have...

And if you don't trust digital cameras, how about a device which measure
the white balance of a scene, telling you how many Kelvin you have?

Those are out there and good to have if you have a studio.
--
teleportation kills