Use and care of Weston 715 and 737 Master III for retro feel?

jay moussy · May 28, 2023

I picked up a Weston 715 and a 737 Master III as a grab bag sale, seemingly both in working order.

Totally new to me, I think I need some clues how to best care, use, and maybe calibrate these, beyond the manuals, which I have, thanks to St. Butkus.

EDIT: they may be used as "retro", often matching my cameras of the era.

I gave them a nice serving of natural light, as I read it is good for cells that have been inactive for a while.

A detail: on the back of the 715, there is a white area, and prior owner (a meticulous guy, judging from other items of his) penciled in something like "set ASA 400 for Ektachrome" or such.

Dennis-B · May 29, 2023

Just a word of caution about selenium cells. They deteriorate over time to some degree, regardless the way they've been stored, or as you state, exposing them to natural light.

To be certain of their sensitivity, you'll need to compare them to a newer meter with a silicon blue, or secondly, a CDS powered one.

The previous user may have personalized the ISO setting for Ektachrome 400. Just hazarding a guess, here.

Bill Burk · May 29, 2023

Wires and springs on the coil are delicate but otherwise they are fairly robust. Sometimes the contacts need tightening and iron dust in the coil needs to be removed for smooth operation.

A drop on concrete can kill them though. And if you sit down with them in your back pocket you can smash the glass.

The Weston III is ASA but the older uses Weston speeds (use the speed one notch lower).

I put Zone stickers on every one I can. These meters are ideal for it.

Check that you get a good 25 reading on both high and low scale with a tungsten light. If you don’t then you might question its calibration.

jay moussy · May 29, 2023

I did a quick check, aiming my small Sekonic 208 and both Westons at the sunny, uniformly dull front grass lawn in front of me, at approximately 10-foott distance.

To match the Sekonic's f-stop/speed read, I need to make the Westons finger dial arrow point to the "Cx2" on the reading range (A, C, Cx2).
I think I am not far off, at a glance, and I may just work on the minute reading of the Weston scales to verify my test.
Matching the Sunny-16 may also be an approach.

Minox · Jun 3, 2023

My Weston Master III had its cell almost dead, and it could not be used at all. Sending the meter to have its cell changed to a new one and calibrated as per original sorted it and now it's in like new condition. The meter is working beautifully.

bernard_L · Jun 3, 2023

jay moussy said:
I did a quick check, aiming my small Sekonic 208 and both Westons at the sunny, uniformly dull front grass lawn in front of me, at approximately 10-foott distance.

To match the Sekonic's f-stop/speed read, I need to make the Westons finger dial arrow point to the "Cx2" on the reading range (A, C, Cx2).
I think I am not far off, at a glance, and I may just work on the minute reading of the Weston scales to verify my test.
Matching the Sunny-16 may also be an approach.

A word of caution. Ageing does not boil down to "x" stops correction. The main effect of ageing is an increase of the internal resistance of the cell. As a result, the loss of sensitivity is larger when the current delivered is largest. That is not just the highest light level, but the highest light level on either range.

Find a surface that reads (A) at the max of the "low" range; you should be able to measure the same surface (B) at the min of the high range. If the measurements agree, good. If the element is degraded, the light level indicated in (A) will be lower than in (B).

Philippe-Georges · Jun 4, 2023

I have about seven of them, US as wel UK made, and only one works decently, the others became 'blind'...
I hardly dear to use the one that works as I fear the degrading of the cell.
But I keep then in the hope that soon or later I would get them repaired.

250swb · Jun 5, 2023

I have no affiliation with this guy and not had any dealings with him but he offers a repair service for cherished Weston meters

https://ian-partridge.com/lightm.html

Minox · Jun 5, 2023

Ian did a very good job restoring my WM III, turning a dead meter into a new-like one.

MartinCrabtree · Jun 5, 2023

I had George Milton (Quality Light Metric) rebuild my Master II about 10 years ago. I believe he's since run out of cells.Great work though it's as new. Find someone to rebuild that knows them and you'll be surprised how well they work. Hell I've even used mine with my F5 to see how accurate it was. And it is on par with the F5 meter.

MattKing · Jun 5, 2023

George Milton has retired, and Quality Light Metric is no more.
I believe Sirius Glass is devastated.

BrianShaw · Jun 5, 2023

Fortunately, sometimes the cell doesn’t need replacing. I have two Master III’s that were successfully revived simply by cleaning the contact between cell and meter.

David Lindquist · Jun 5, 2023

MartinCrabtree said:
I had George Milton (Quality Light Metric) rebuild my Master II about 10 years ago. I believe he's since run out of cells.Great work though it's as new. Find someone to rebuild that knows them and you'll be surprised how well they work. Hell I've even used mine with my F5 to see how accurate it was. And it is on par with the F5 meter.

Probably not less than 10 years ago. I have a note dated November 2013 that I talked to George Milton and he said there were no more cells for the Weston meters as the company in England that made them had gone out of business. Per a thread in the large format photography forum, George retired about March 2021.

I wonder where Ian Partridge gets his cells. I bought a Weston Master IV from him a few years ago. There's a certain je ne sais quois about that dial graduated in candles per square foot...

David

Minox · Jun 5, 2023

Ian repaired mine some 8 yrs ago. From what I gathered, he builds them cells from larger ones, which he procures. It is also my understanding that these larger ones are very scarce and the modifications needed for the WM cell are somewhat complicated. Therefore, a lot of work goes into repairing these old timers. Other than that, no idea.

eli griggs · Jun 5, 2023

MattKing said:
George Milton has retired, and Quality Light Metric is no more.
I believe Sirius Glass is devastated.

No just Sirius, I had two Weston V's done by him and have a pair of IV,'s I wanted done, when my budget had upswing.

If you're ready to take a chance, take double sided, adhesive copper tape and bridge the cell to the wire connection and see if this revives your IV or V.

I've read this is sometimes the ticket to saving a meter with bad/corrupted cell wire to meter connections.

Also, open your meter cell to sunlight for a few days, as this is a way to rid it if oxides that may have built up and impacted readings.

Cheers

MartinCrabtree · Jun 5, 2023

David Lindquist said:
Probably not less than 10 years ago. I have a note dated November 2013 that I talked to George Milton and he said there were no more cells for the Weston meters as the company in England that made them had gone out of business. Per a thread in the large format photography forum, George retired about March 2021.

I wonder where Ian Partridge gets his cells. I bought a Weston Master IV from him a few years ago. There's a certain je ne sais quois about that dial graduated in candles per square foot...

David

According to the little yellow sticker on the back it was done 4/22/10.

Use and care of Weston 715 and 737 Master III for retro feel?

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