Vintage Stuff Part 1: SEI Exposure Photometer
December 17th, 2009 § 10 Comments
The SEI Exposure Photometer with leather bag. Click to enlarge. Photo by Øystein Horgmo © All rights reserved.
The cupboards and shelves at the Photographic & Video Services, my new job, are filled with old photo equipment, collected throughout the department’s history. In this new post series I’m going to pull some of the more interesting items into the strobe light. The first item is the SEI Exposure Photometer, a truly remarkable vintage gadget.
When I found this heavy metal rod thing, I couldn’t figure out what it was. The label suggested it was some kind of light meter, but it looked nothing like any other meter I’ve ever seen. A quick web search revealed that not only was it a light meter, but it is one of the most accurate reflected-light meters ever produced.
Produced by Salford Electrical Instruments (SEI) in the UK from about 1948 to the 1960s, it used to compare the brightness of a subject with the brightness of a lamp inside the meter. As the lamp’s brightness is predetermined, the brightness of the subject can be assessed and translated into correct exposure.
Left to right: Too bright spot, correct measure, too dark spot. Photo by Øystein Horgmo © All rights reserved.
The comparing is done by looking through the 1,3x telescope. In it you see a spot in the center (actually smaller than the mock-up above). The spot is placed on the subject area you want to measure. You press a button to turn on the lamp, and then rotate the base of the meter to adjust the brightness of the spot. The correct measure is found when the spot disappears (above center).
Exposure settings can be read from the tables on the meter’s barrel. You can choose a shutter speed and find the correct aperture, or vise versa.
The barrel with shutter speeds to the left and f-stops in the middle. For 1/200 the correct aperture would be ƒ/5.6. The numbers to the right are used to set the film speed (in British Standard Log speeds). Click to enlarge. Photo by Øystein Horgmo © All rights reserved.
For the sake of illustration I used “measured” a part of the barrel in the example above. But to determine exposure you must measure the darkest part of the scene that you want to have detail (negative film), or the brightest part that you don’t want to clip (slides, movies, digital photography).
Although they stopped making it a long time ago, it’s still used by some Hollywood cinematographers for its extreme accuracy.
So the next time I’m heading over to the OR, I’ll bring this along, have it sterilized and measure those deep crevasses of the abdomen. Or maybe not.
Sources:
Ansel Adams used one of these meters and wrote about it in his basic photo series. In 40 years of photography I have never actually seen one.
What wonderful shelves, what a wonderful place. My personal Jerusalem is currently Photographica in Copenhagen, or just browsing the net… wonderful places like Cameraquest.com. Anyways, there seems to be more photographic… Meccas :)
Thanks for the tips, Peter!
Going to Copenhagen this spring, so I’ll try to pop by Photographica. Where is it located?
I have one and am about to put it up for auction on eBay.
Hello
this an open letter to SEI meter enthusiasts … I have an SEI with the original manual that has recently stopped working. NOW i am not going to fix it SO
anyone who is willing to pay the price of the postage can have it ( and hopefully be able to fix it
regards
thomi wroblewski
london uk
I’m interested in the SEI Photometer if you’ve still got it.
Is there any chance you could send me a copy of the manual, I have one but do not know how to operate it. I would really appreciate any help you could provide.
Thank you,
Kit Cole
Kit: The manual is available online here: http://www.jollinger.com/photo/cam-coll/manuals/meters/SEI_Photometer.pdf
Thanks, for the information. Someone just gave me one with the case, but it didn’t come with a manual, hopefully it works.
I worked at SEI for 9 years from 1963 during my time there I spent 2 years repairing SEI Photometers, sadly manufacture & repaired stopped when Charlie who I trained retired. I think Zoomar in the US bought all the remaining parts & tools which would be either late 60s or early 70s.