AVO Light Meters

[Paul Adams]

Not too sure if this is considered O/T or if it’s in the right place, however I have started collecting a number of the small AVO photographic light meters, as shown below.

I am not particularly interested in photography, I bought them because mainly they had the famous AVO logo on them and they looked an interesting item and they don’t take up too much space, which at the moment I am running out of, all taken up by AVO’s as the last picture shows. (I couldn’t get all of them in the photo, as there are more to the left of the picture)

Anyway see what you think….


Paul.

Super collection, I also collect photographic stuff, it is fun to go out with some 1920's gear and take photos. Here is my oldest light meter (in full working order).

[Paul Adams]

Thank You for your comments,

I also have this one on it's way.....

Paul.

[MrElectronicman]

Never heard of an AVO light meter before. I have, what was at one time the de facto standard for amateurs, a Weston Light meter

[MrElectronicman]

I must say I like your collection of AVO multimeters, this must be why I cannot find any.

[noble kiwi]

I acquired an Avo light meter because I was fascinated that it was styled as an exact miniature of the traditional Avometer and makes an interesting addition to my collection. It is scaled simply in foot candles and is not designed for photography. It appears to have remained fairly accurate.

It is the same as that shown in Paul’s second photo and has a closely fitting blue leatherette case. It came with the same blue covered instruction booklet showing a price of 45/-. My guess is that it was manufactured late 1930’s. Can anyone provide more exact information?

Trevor.

[wd40addict]

I have an AVO light meter somewhere which belonged to my Father. It's a different model to any shown although vaguely like picture 4. It's black and has a wrap around rubber case. Was still working when I last tried it. However there is an issue: The meter has a high and a low range achieved by by moving a shutter in front of the cell when the knob is turned and this mechanism is none too reliable. It's also best used with old cameras such as my Zeiss Ikon because the speed sequence is 1/25, 1/50, 1/100 etc, not the more modern 1/30, 1/60, 1/125 (when and why did this change I wonder?)

Regards,

Paul

[Alan Stepney]

I had two Avo lightmeters, one the same as photo4.

I found (or thought) that they read low compared to the Weston meters I had.

[Phil G4SPZ]

Paul, just a quick question about Avo light meters - can you tell me if they are calibrated in foot-candles, and if so, what is the range? I want to measure the light output from vintage Tilley lamps and was thinking of getting a vintage Avo light meter for the purpose!

All the best,

Phil

[Refugee]

My attention went for the one on the bench as it has a different shape to the glass and also the display arc looks bigger.
Curious.

[Paul Adams]

Phil,

The AVO model 2 light meter has the scale marked 50-foot candles and 500 lux.
The higher range is introduced by means of a switch and, at the same time, an indicator marked with a multiplying factor of X5 is moved beneath a small aperture in the scale plate, as shown in some more pictures.

The other models I have are mainly marked in ‘f-stops’ if that’s the correct terminology, and some that I have, are just a blank scale plate.

Don’t really know if they are accurate, as they all give slightly different readings, and I don’t have anything to accurately calibrate them against.

Paul.

[Phil G4SPZ]

Hi Paul and thanks for the info. Does the x5 range increase the full scale reading to 250 foot candles or 2,500 lux? 1 foot candle is generally taken as being equal to 10 lux for all practical purposes, hence the dual scaling. I want to measure a light source of up to 250 foot candles, hence my questions!

Many thanks.

[Paul Adams]

Phil,

From what I can make out, I think the X5 range increases the range to 2,500 lux, and 250 foot candles.
The scale of the meter appears to be logarithmic, you are welcome to come and borrow a couple,(give me a call) before you buy one from somewhere if you want, but I wouldn’t vouch for their accuracy as I have nothing calibrated to compare them against.

There’s one HERE and HERE if you fancy buying one though.

Paul.

[wd40addict]

Phil,

Can I ask how do you plan to convert from foot candles to candle power? My Gossen Lunalite has a table to allow foot candle conversions of readings taken in the incident mode. Eg with the white dome over the sensor and pointing the meter at the source (usually a cine projector ) The standard for doing this is to project a 3 foot wide picture. My results have tallied well with published reviews etc.

Most Tilley lamp are notionally 300cp and the light is thrown a full 360deg round the lamp. So the meter would only be receiving a tiny portion of the light. If there's a way of doing it though I would be interested to try it (suspect my Bialaddins will be brighter than my Tilleys though)

Most 'proper' foot candle meters seem to be the incident type. So if you buy an old AVO make sure it's got the white plastic square to go over the sensor. From memory my AVO has, but having moved house I don't have the meter to hand to check.

Regards,

WD40

[Phil G4SPZ]

Paul, thanks very much for the links and I'll probably buy one at those prices.

Hi WD40,

I mainly want to do comparative tests, e.g. one Tilley versus another, or with different mantles, pressures etc. However, from what I've researched, if you take the reading at a distance of 1 foot from the light source, the result is indicated in candela direct, although this of less interest to me than the comparative measurements.

Sorry Mods, if you think this discussion is going OT we can go off to continue it on a vintage lighting forum!

[Refugee]

Originally Posted by Phil G4SPZ

Paul, thanks very much for the links and I'll probably buy one at those prices.

Sorry Mods, if you think this discussion is going OT we can go off to continue it on a vintage lighting forum!

We will be fine here. We are talking about AVOs here after all

[wd40addict]

If it's just comparative tests you're after I think almost any meter will do as long as you tilt the meter to peak the reading in each case.

My money's on thorium mantles!!

Regards,

WD40

[pmmunro]

There are really two themes to the Avo lightmeter range; photographic exposure meters and illumination meters.

It is possible, although hard evidence is lacking, the the photographic range resulted from Hugh S MacAdie's interest in photography and it may be that he thought his company was well placed to diversify from electrical to light measurement.

The assembly of Avometers is precision work which is facilitated by good lighting; I think I have seen a reference to the company's need to ensure that adequate lighting was available and it may be that they thought that their need pointed to an industrial and general market for illumination meters.

PMM

[paulsherwin]

Reopened by request.

[Superscope]

Thanks Paul,


I came across a Photo on-line, which is probably the first Light Meter, and
certainly the first Exposure Meter, made by the Avo Company.

Thought it might be of interest to some on the Forum, and thought this was
the best place to post it.
Is this the oldest resurected Thread I wonder?

Clearly, this was not an Avo (ACWEECO) design, and appears to have been
manufactured for Smethurst High-Light, Ltd, and both Names are shown.

Slightly more information can be found on the Website I robbed the Photo from,
although there are a number of errors regarding ACWEECO on there.

http://www.jollinger.com/photo/meter...smethurst.html

I've never seen this Meter before, and it looks like the Owner hasn't seen another
one since either.



Ian