Adams' Zones and my "Weston" Master 6 Light-meter

The model 6 p/n 560 is actually said to be made under license by Sekonic, neither by Weston nor by Sangamo-Western. Mine came with the optional Adams Zone dial, which is why I bought it out of interest.

Took me a while to figure out the Adams Zones bit. There's a small arrow where "V" should be. Basically, it gets pointed to the meter reading on the inner dial by rotating the outer dial. Pick the desirable resulting aperture/shutter combo and the metered object will render as middle luminance i.e. the object will be "placed" in Zone V. To place an object, e.g. snow, in a lighter Zone, rotate the outer dial until perhaps "VII" is pointing at the meter reading ... or, for the proverbial coal heap, rotate the outer dial until "II" is pointing at the meter reading. These additional rotations change the exposure appropriately and are equivalent to Exposure Compensation now that the Zone System is almost forgotten.

To test the degree of compensation for snow, I figured the Exposure Value recommended by the illustration above - it is 13 Ev. (from log2(N^2 / t).

Then I turned the outer dial to align "VII" with the same meter reading on the inner dial - sure enough, the recommended Exposure Value changed to 11 Ev ipso fatso.

I made a home made zone scale that I placed on Pentax Spot meter back in the day. The spot meter was a great tool with film. My modern digital cameras have made it obsolete.

Cool. There's a guy still selling stick-on Zone scales for various light-meters.

www.shutterspeedblog.com/

For a Weston Ranger 9:

For a Pentax spot-meter:

I still have my Pentax Spotmeter V with my homemade zone scale stuck on it plus two Weston Master V meters with improvised zone scales on them. Sadly the selenium cells in the Weston Masters are shot. I also have the Bronica 6x6 with its set of Nikkor lenses and some unexposed 120 film - so who knows, one day…

best wishes

A

I ordered this Master V a couple of days ago hoping that the cell is still good:

www.ebay.com/itm/147007051917

i did a test yesterday the see how accurate the spot meter was on my a7iv compared to the muilti metering with the subject covering the whole frame. they were 1 stop apart, so not real accurate.

What did you shoot, a wall ?

Ron

Donald, how did you measure the accuracy of the spot-meter? Did you know the luminance of the presumably homogenous subject? Do you know the K constant of the camera's reflective metering? If you did, you could see if the reflective metering equation t/(N^2)=K/(SL) balances ...

For example, if f-number N=8, const K=12.5, ISO S=100 and luminance L=2000 then shutter period t should equal (N^2).K/(SL) = 1/250 sec.

<deleted by author>

i used a 500x500mm concrete stepping stone lit by clouded natural sun light. i didnt take an image just the camera exposure reading.
i also went to use my vintage light meter that ive had for years and the cell has gone 😌 so i pulled it apart and there is not even a resistor in sight just the cell
and the meter.

Do you remember the readings?

I estimate that your spot-meter function should recommend about 14 Ev for concrete under that lighting. If you shot at f/8, that would work out to 1/256 sec - pretty close to my earlier estimate.

Sorry to hear that. However, there is actually no need for a resistor in vintage selenium-cell light-meters; the meter itself is scaled to match the cell output characteristic i,e, scrunched up at both ends. See my earlier shot of the Weston 6 meter.

See for example the difference in distance between 32-64 and 125-250. For true log2 scaling they would be equal distances.

Just received my fancy luxmeter which can also display foot-candles (fc). So I put my Weston 6 under the desk lamp - it told me 24 fc. Then the luxmeter set to fc - it said 51 fc. About -1 Ev error if the +/- 5% accuracy luxmeter is to be believed.

But the Weston is designed for reflective measure and the luxmeter obviously for incident measure. Hopefully my "new" Master V will come with the 'Invercone' accessory which converts it to an incident light meter, allowing a more proper comparison.

i will do another test and let you know what the readings are, i have a pentax ME somewhere, might have to find it and see what it reads.

Thanks Donald. Looking forward to them.

[edit] duh, I didn't know that the ME is camera. So when you find it, this might be useful:

www.youtube.com/watch?v=0qOGD_O2GqI
[/edit]