Try to put yourself in the place of an engineer tasked with building a camera in 1961. Your specs include making it easy to operate, giving it automatic exposure control, and, oh yeah — you can’t use batteries. How on Earth do you accomplish that? With a very clever mechanism powered by light, as it turns out.
This one comes to us from [Alec Watson] over at Technology Connections on YouTube, which is a channel you really need to check out if you enjoy diving into the minutiae of the mundane. The camera in question is an Olympus Pen EES-2, which was the Japanese company’s attempt at making a mass-market 35-mm camera. To say that the camera is “solar-powered” is a bit of a stretch, as [Alec] admits — the film advance and shutter mechanism are strictly mechanical, relying on springs and things to power them. It’s all pretty standard camera stuff.
But the exposure controls are where this camera gets interesting. The lens is surrounded by a ring-shaped selenium photocell, the voltage output of which depends on the amount of light in the scene you’re photographing. That voltage drives a moving-coil meter, which waggles a needle back and forth. A series of levers and cams reads the position of the needle, which determines how far the lens aperture is allowed to open. A clever two-step cam allows the camera to use two different shutter speeds, and there’s even a mechanism to prevent exposure if there’s just not enough light. And what about that cool split-frame exposure system?
For a camera with no electronics per se, it does an impressive job of automating nearly everything. And [Alec] does a great job of making it interesting, too, as he has in the past with a deep-dive into toasters, copy protection circa 1980, and his take on jukebox heroics.
Thanks to tipping stalwart [Keith Olson] for this one!
“And what about that cool split-frame exposure system?”
https://en.wikipedia.org/wiki/Rangefinder_camera
“And what about that cool split-frame exposure system?”
Means it takes half size images so you can take twice as much images per film.
I have an Olympus Pen EE, bought by my dad when he was in Vietnam in the 60s. I used it through high school, and the benefit of getting twice as many frames was that I spent a lot less money on film. Only trouble was that the Pen EE only had settings for film up to ASA 200, meaning I was restricted to Plus-X and couldn’t shoot the faster Tri-X. Color film was out of my budget.
I still have it, and it worked the last time I used it. Maybe I’ll pull it out of the drawer and give it some exercise.
The easy way to get around the ISO limitation, is to buy some neutral density filters that fit over the lens and meter, reducing the light coming in, so the camera responds correctly. If you still want to shoot Tri-X (it’s still in production) just get a ND2 filter to cut the light in half for the ISO 200 on the camera.
Well, in this case you would also cut the light in half which reaches light sensor, so you’re not really solving the problem.
You could solve it by going with manual settings, but that is quite fiddly on the Pen EE camera.
True, ISO 400 Tri-X was fast for its time, at the expense of graininess. ISO 200 Plus-X has finer grain size. And, at the time (please don’t take my) Kodachrome was ISO 25!
This is an excellent look into the fantastic tech. The tech I grew up with.
five stars
I had a great little light meter from the 1960s… though I had it in the 80s… ran entirely off it’s cell output. I wanna say it said Coronette on it, but might be conflating it with something else. Anyhoo, lasted up to a family event where a young cousin was fascinated by it “lemeesee lemeesee” etc, until I was co-erced into “let him hold it, what harm could he do” whereupon he held it carefully for all of 5 seconds then whirled it around his head on the strap and smacked a brick wall with it. Nobody was adequately sorry.
GE meters were pretty common for that.
Abortion should be legal up to the 87th trimester or 4 trimesters after they last ask their parents for money, whichever is later.
I have one of these and was meaning to post a (much worse) video on it. I noticed he had one too long ago on his shelf boxes.
Great video of a sophisticated design using limited technology. A cruder camera from 1960 was the Ricoh Auto Half, available rebadged as the GAF Memo II, which had autoexposure with a single shutter speed.
My experience with old photocells is that they tend to degrade over time, perhaps because they are poorly protected from the atmosphere.
I read this mentioned lot of time, but 40 to 60 years old selenium-cell cameras that came into my hand always had spot-on exposure, maybe it was just luck. I had worse times with CdS cells supposed to be powered by mercury batteries. I tried different modern cells, the schottky diode hack, but never got it right, 1/2 stop off at best.
I have heard…that keeping the lens cap on when not in use will slow the degradation. Something about keeping them dark prolongs their life. I don’t know the physics behind this, but mine still work and the lens caps are always on.
Retrotacular tag?
I’ve only recently found a battery that’s supposed to replace the 2 MR9 mercury cells used by my Gossen lightmeter – but it’s going to take some adjustment.
It’s a pair of 1.35V alkaline cells shrink-wrapped together, but I had to get creative to make it fit into the battery compartment on the lightmeter.
The first test was about half a stop off, even though the voltage was fine at 2.7
I can help there. There is an adapter (not cheap) which allows use of a silver oxide cell. This pdf explains your options far better than I can. I have one of those adapters in my LunaPro and it does the job.
https://www.butkus.org/chinon/batt-adapt-us.pdf
Two NiMHs should have the same voltage.
The other problem with replacing mercury cells is that they usually imply a mechanism that has very little voltage regulation and requires the voltage curve to be almost constant for the used life of the cell. So that’s why silver batteries and voltage adjustment may be preferred.
“Solar powered” is just clickbait.
Nothing especially spectacular about this. Back in the day lots of cameras had built-in selenium light meters like that.
What else would you call it that might have some inkling of recognition in the way it works?
If you had maybe read the article you would see that it does more than twitch a hairlike needle on a very delicate tiny movement.
I did read the article.
I actually USED such cameras back in the day.
“Solar powered” is a stretch to the breaking point.
Clickbait.
It’s more solar powered than most solar powered calculators I’ve had. And it uses the cell to perform all the functions my AE-1 performs with a battery and we call that battery powered. Almost no pre – AF cameras did much more than it does with their electrical systems. It’s just unusually simple in how it does it.