Antique Mechanical Exposure Meter

[nhemann]

Saw this little guy today as I was killing some time on the Internets. How cool would be to have one of these?

 

[Ian Grant]

Kodak had a more modern version that came with a small book, and I think I have one from Johnsons of Hendon as well.

Alternately there were the exctinction meters

Ian

 

[Hexavalent]

Ooooooh!!! I want, I want!

 

[vpwphoto]

Remember; no two lightmeters ever agree, and I doubt this thing was as accurate as anyone saying "cool" gives it credit for.

If it worked that well, there would be similar devices that worked for trig rather than the 1 dimensional slide rule of days long gone.

 

[nhemann]

remember; no two lightmeters ever agree, and I doubt this thing was as accurate as anyone saying "cool" gives it credit for.

I'll give you the benefit of the doubt in assuming that your above comment was more comedic than the extremely condescending it comes across as - but ask you to delete it anyway.

If I wanted modern accuracy, I'll use the electronic one I already own. If I want steam-punk cool this is the ticket - don't be so serious. I didn't say you had to like it.

Neil

 

[Ian Grant]

It would be very cool to opwn one of those Meanwhile I make do with my pre WWII AVO meter and extinction meters and exposure index tables (which this sort of automates) in early BJP Almanacs

Ian

 

[nhemann]

I had never heard reference to an extinction meter before so thanks to google and you, I am a better, smarter person today. Thanks!

 

[Lightproof]

I love mechanical calculating devices. I already have a Curta, a planimeter, some slide rules and so on.

And thats the thing I want to own next, thank you!

 

[Chan Tran]

It isn't an exposure meter but rather an exposure calculator or computer. May be we can write an app to do that on the PC, Mac, IPhone, Andriod etc....?
The important thing is the app must use the information on the mechanical device that you have whether it's good or bad.

 

[nhemann]

Indeed, well noted. Exposure calculator - the excitement forced technology ahead of my terminology.

A pseudo steam-punked emulator of this device for the iphone would be hysterical........

 

[nhemann]

An incidentally, for any and all the mechanical engineer/designers out there. How the heck do you go about designing that?

 

[removed account4]

i just bought an instoscope from a fellow appugger the other day ..
it's an extinction meter ... the only problem i have is it uses
the ancient schneider speeds instead of asa/iso values
and the meter only goes as high as the equiv of asa 100 ...
but i just learned today how to do 2x filter factors so it will work just fine
it's almost as easy as sunny 11

 

[vpwphoto]

It is cool... I like gizmos thanks for sharing.

I was just stating a photographic maxim, I have always known, and most of also know that few gizmos other than a light tight box and focusing lens are needed.

Way back in the day there were "light meters" that used some photo-sensitve paper and a timer, to judge the intensity of light to make a more accurate exposure. They were neat little brass and ivory cylinder things with the light sensitive paper inside.

 

[Two23]

I've been using a Zeiss Diaphot from the 1920s for my b&w exposures. It's pretty nifty!


Kent in SD

 

[Bill Burk]

I particularly like the Zone 1 to Zone 5 cross-hatching. Maybe this was partially at the root of the Zone System?

 

[steven_e007]

I think that is a wonderful device, made in the days when watchmakers and craftsmen made 'computers' out of brass.

It will be compromised by nature of it using an obsolete systems for film speed and possibly aperture as well, but the principle of calculating exposure, rather than measuring it, is sound. The idea still has advocates:

http://www.fredparker.com/ultexp1.htm

The real challenge would be to make a 'modern' version with a familiar ISO speed range. No reason why it shouldn't be a useful tool. I carry around cardboard depth of field calculators and widgets to calculate bellows factor. Never feels right pulling out a modern spot meter with a wood and brass camera.

Not sure I like the 'app' on a phone idea, though. IMHO, If the thing can suffer battery failure - it ain't steampunk! Get the brass out and start filing ;-)

 

[Rick A]

What a beautifully designed widget! I still carry around 1940's and 50's exposure calculators, much lighter(intended) than a meter, more convenient and, easy to use. I would definitly carry one of these if I had one.

 

[2F/2F]

Mechanical exposure meter...sounds impossible to me.

 

[bsdunek]

In my early engineer career I used Friden mechanical calculators, planimeters, and other neat mechanical devices. I kind of miss them. Batteries never failed. I would like one of these - very neat.

 

[vpwphoto]

Got to get an extinction meeter... I like the concept. Surprised I haven't run across one in my years of messing about.

Photographed my first summer using the little card placed in Kodak films.

 

[Matthew Rusbarsky]

I've been using a Zeiss Diaphot from the 1920s for my b&w exposures. It's pretty nifty!


Kent in SD

Cool! Do you actually find it useful? How well does it perform in low light?

 

[Chan Tran]

I wouldn't carry an exposure calculator or chart. Because one can always learn and remember.

 

[Jeff Kubach]

I kinda like it. Sure is neat!

Jeff

 

[BrianL]

I have a few extinction meters that were given to me over the years and I'm surprised just how easy and accurate they be. Even with no practice you can come within 1 stop of a modern meter and once you dial in the eye to the extinction meter over a short time I can get the same result. I do not use them but they make interesting discussion pieces and are rapidly being forgotten, I think. I also have a Curta sitting on a shelf in its plastic container. An interesting calculator designed by an inmate in a NAZI concentration camp.

That mechanical meter seems to have spawned the exposure chart on the earlier Roleiflex. A simplified version that takes into account the time of year, something modern meters do not.

 

[steven_e007]

I've been having a really good close look at this Kaufman Posographe.

Printing off the pictures as A4 and then googling some of the French into English helped a lot

There must have been a whole technology of mechanics years ago that, if not forgotten, is now ignored by most of us. I did a bit about first, second and third class levers when I was at school - that was it. There is obviously a lot more to it than that. Fascinating to sit for a few minutes and work out how this works. It obviously uses well understood principles and I guess it probably wasn't too difficult a task to design at the time.

From a photographic point of view, it calculates exposure from Month, Time of day, Scene, weather and colour & lighting of the subject. Interior views use colour of light and colour of walls, I think (I haven't translated that bit, yet) and the 'zones' are the distance from the window.

There seems to be an emphasis on colour presumably because this would have made a big different in the days of 'ordinary' and 'orthochromatic' emulsions.

One thing that is missing is film speed! This is accounted for by the output display unit (the oblong brass widget) having four pointers on it. these are designated Ordinary, rapid, extra rapid and ultra rapid. I think they refer to specific plates and the spacing between them isn't even. They could be the equivalent of something like 2, 8,16,32 ISO, maybe? (Would Ultra Rapid have reached ISO 32 in the 1920?)

It seems to be it is a pretty comprehensive calculator that takes into account most factors and I reckon would have worked well, with the four types of plates it was intended for in the 1920s.

Most modern exposure calculators use only a scene description with a sliding scale to calculate different aperture / shutter combinations for a variety of film speeds.

The idea of a modern version of this more comprehensive calculator, which puts film speed into the equation as an input variable and perhaps places less emphasis on colour, sounds intriguing