The AVO Exposure Meter Comes Full Circle

<p >The AVO exposure meter was an Ebay acquisition coming from, if I recall correctly, somewhere in the South West of England. It's quite a small but heavy meter in a black leather case, not much bigger than a 35mm film box. What I like about it is that it is very sensitive to light, probably because of the relatively large selenium cell, which is deeply recessed in the body so as to be highly directional, almost like a spot meter, and I'd like to use it in action.</p><div></div>

<p >The inscription on the back reads “Made in England by the Automatic Coil Winder and Electrical Equipment Co. Ltd, London SW1”. But the company was better known as AVO because of its well known multi-meters (Amps Volts Ohms). There's a good page about them here, sorry the author's name isn't easy to find on the site which is mainly about the Weston meters: </p>

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<p ><a href="http://www.westonmeter.org.uk/avo.htm">http://www.westonmeter.org.uk/avo.htm</a></p><div></div>

<p >The film speed setting is marked “H&D” and runs from 200 to 5000. That's a film speed scale called Hurter & Driffield after the two scientists who first tried to standardise the speed ratings of film. There's a great explanation of these obsolete rating systems on James Ollinger's website here: </p>

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<p ><a href="http://www.jollinger.com/photo/meters/other/speed_table.html">http://www.jollinger.com/photo/meters/other/speed_table.html</a></p>

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<p > According to this there were actually three and perhaps four quite different H&D systems, so I don't know how to relate the scale on mine to current ISO numbers. However I found that the meter gives the right exposure for 200 ISO, with the pointer lined up with the D as shown in the picture, i.e. way off the H&D scale. It seems that ALL of the H&D speeds are slower than ANY current speeds. If I'm going to use it I will have to spend some time calibrating it against a modern meter.</p><div></div>

<p>The really nice thing about the meter however was the sticker on the base, seen on the first picture:</p>

<p>H. G. Thompson, Cameras and Home Cine Apparatus, 5 Northampton St., Leicester.</p>

<p>So, it had been bought right in my own home city! And the shop is still there, although now it's a lettings agency, but I can imagine hard up enthusiasts in the 1930's, staring longingly at the cameras and home cine apparatus in the little shop's windows.</p>

<p>Hope this has been of interest and thanks for looking.</p><div></div>

<p>Always interested in finds like this. Thanks for sharing.</p>

<p>Pretty nice. </p>

<p>Even though the film speeds don't go up to modern slow films, the shutter speeds go to 1/2000, and aperture to f/32. Not likely used much with ASA 6 films.</p>

<p>Nice find, <strong>John</strong>. I've been looking at the background of these meters, recently; this model was apparently the invention of one Donald Macadie, a Post Office engineer. Also available was the Smethurst High-Light Meter, invented by British photographer Philip Smethurst, patented in 1937 and considered to be the first meter able to read incident light. The two meters are similar, both having been manufactured by the Automatic Coil Winder and Electrical Equipment Company, better know as ACWEECO, or AVO, as you explained. I'll post a couple of pics of the Smethurst with an example of the AVO; both the meters are still reacting strongly to light, though I share your mystification with the H&D system.</p><div></div>

<p>No.2</p><div></div>

<p>Nice find and interesting story. Thanks for sharing. Nice images too.</p>

<p>Thanks for the post. I really enjoyed it too. The full circle indeed it is very interesting to find something that you can match up in the modern era. I have a box camera with a sticker being sold/given away in the 1930 by an optic and hearing aid company that is still in business.</p>

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<p>I think that that's really wonderful, but I wouldn't use it to set exposures for any important pictures.</p>