Weston Master V – a Review of the Masterful Exposure Meter

I confess the company history around the Weston meter leaves me a bit confused. There were lots of mergers and buy-outs over time on both sides of the Atlantic. Sangamo and Weston were originally both US companies that started UK subsidiaries. In the UK, the two companies merged in 1936.

Sangamo Weston still had links back to its original parent companies in the US. They all made electrical measuring instruments, including ones to measure the intensity of light. These were in demand for both photography and moving picture production. A candle-power meter made by the Weston company was used during the production of ‘Gone With The Wind’.

In 1939 the Weston company in Newark NJ produced the first ‘Weston Master’ light meter. From 1947 this model was produced by Sangamo Weston in Enfield in the UK. By that time the NJ plant had switched to making an updated Master II. Sektonic also appear to have started to manufacture a version of the Weston II under licence from around 1953.

In 1956 both Weston in NJ and Sangamo Weston in the UK started to produce the Master III, which was the first of the meters to feature ASA film speeds (previously a proprietary nominal scale seems to have been used).

In 1962, Schlumberger took over the US company. Later versions of the Master were only made in the UK, or by Sectronic under licence in Japan. The subject of this review, the Weston Master V, was made in the UK between 1963 and 1972.

More details of the history of the Weston meter and of the many different models produced over the years can be found at westonmeter.org.uk. It is both informative and very well maintained. Go there for an education on light meters in general.

Master V features

The Master V meter is a neat little unit. It is finished in brushed metal and grey plastic. Intensity of light is measured by a large round selenium cell on the back of the meter. In normal use (outdoors), the selenium cell is covered by a baffle with holes in it. In low light (indoors), the baffle can be folded back, at which point a different scale (for low light) is shown.

Film speed readings are input by pressing a little lock button at the NW position on the dial while turning the centre disk.

The numbers that the meter needle points at are quite arbitrary (earlier scales were in lumens), but the key thing is that they sit a stop apart. You take a reading by pressing the little button on the right side of the meter; this frees the needle, which then locks in place when the button is released.

The value from the meter is then transferred to the circular dial, aligning the big red wedge pointer to the appropriate red ‘LIGHT’ number. Once this is done, you can either choose one of the f-stop/shutter speed combinations shown on the edge of the disk, or you can read off the Exposure Value (EV) number and set that on your camera (if your camera uses EV values).

All this is quite straightforward and quite common to other light meters. So what is special about the Weston V and its stable-mates?

It is a robust, convenient and well designed little meter. I first came across these when I was doing a photography course at school (I had persuaded the school to run it for sixth-formers). The standard cameras the school got in were Practica m42 mount cameras with built-in meters but the school also got in some Weston meters (I think the V, although it would have been out of production for a few years by then). The Weston was impressive enough that I picked one up for myself a few years ago.

The other nifty little feature of the Weston Master meters is their ability to take incident light readings when using an ‘Invercone’.

Invercone

In truth the Invercone buggers up the ergonomics of the Weston V quite a bit. It goes from being an instrument that can simply slip into a pocket, to something that is twice the depth and can separate into two bits rather more easily than anyone would like. However, it does work and can be very useful for ‘tricky’ lighting situations. Simply put, rather than measuring the light reflected from the subject and assuming a roughly 18% reflection of light, you hold the light meter and Invercone in front of the subject, pointing back at the source of light and take your reading from there.

Now, incident light readings are not unique, but the Invercone claims to be shaped to reliably meter light falling on the subject from a number of angles. I’ve even seen a claim that the bit where the cone overlaps the top of the Weston V is a deliberate design to also capture an element of backlight. Personally I’m a bit sceptical about that, but it has to be said that the Invercone works.

Exposure Values

They were never all that common, but some older cameras use an Exposure Value (EV) system. These allow you to manually set an EV value which locks the shutter speed and aperture together, meaning that you can effectively ‘shift’ the exposure by moving both rings together. As you do this the shutter speed and aperture maintain the same exposure. It is a great system for use in circumstances where the overall light stays the same. Effectively, you meter once, then shoot until the light changes.

I have just two cameras that use Exposure Values, one is an aged ‘Super Frankarette’ with an f/2.8 Schneider-Kreuznach Xenar lens, and the other is an Olympus 35 SPn.

If I set an EV number for either camera, it should show the same set of f-stop and shutter speed combinations as shown on the Weston meter. I decided to experiment and the results were… inconclusive.

Set to an EV of 12, the Olympus suggests the same 1/60 at f/8.0 (and equivalents), as the Weston V. However, the Super Frankarette suggests f/5.6 to go with 1/60. It is ball-park but I’m curious as to why the older German camera wants to let in twice the light that the Weston and the Olympus think is appropriate.

Why?

Why would anyone want a Weston Master meter in 2025? We are surrounded by lots of clever devices that allow us to gauge exposure very well. We have built-in TTL meters, spot meters, matrix meters, clever little meters that clip into camera accessory shoes and even apps that turn a smartphone into a sophisticated light meter. On top of this, our films generally have enough latitude to tolerate some really quite bad exposure choices.

Let’s face it, from a purely practical point of view, it is difficult to justify shooting any analogue camera in a modern environment. But at the end of the day, they are nice bits of kit. A lot of vintage cameras are now very expensive, but the Weston Meters are, at time of writing, quite affordable. When you use one, you realise that you are using something that works exceptionally well. It is at the top of its tree, second to none. I don’t need one, but I like using it.

After the V

Following on from the V, Sectonic made a Master 6 in Japan but production would seem to have stopped in the mid-1970s. Sangamo Weston produced a Weston Euro-Master model in 1973. The Euro-Master looks to be quite similar to the V, but with a less busy dial. It was manufactured in Enfield until 1980. At that point, Sangamo Weston decided to get out of light meter manufacture.

After Sangamo Weston stopped making light meters, a former member of staff set up a company in East Kilbride (called East Kilbride Instruments) to continue production. At this time the Weston name was dropped and so the East Kilbride meters are simply labelled Euro-Master. When East Kilbride Instruments went into liquidation in 1984, manufacture was taken on by Megatron. Although it may sound like an evil robot, it was actually a company specialising in photoelectric cells, based in Tottenham. Megatron introduced a Euro-Master II in 1985. They continued to produce the Euro-Master II until they, in turn, went out of business in 2010.

The Sangamo name still lives on in the UK as a company that manufactures time switches and heating controls in Port Glasgow on the banks of Loch Lomond. The metering division of the old UK Sangamo now operates out of Felixstowe in Sussex as Iton Metering Solutions.

Sectronic still make light meters.

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