It’s true. The Kodak Signet 50, a spiffy plastic scale-focus 35mm camera from the late 1950s, has a thoriated glass element in its 44mm f/2.8 Ektanar lens. It’s also a pretty cool little camera.
Thoriated glass — glass made with a high concentration of thorium oxide, a low-activity radioactive molecule — has a high refractive index. This allows lens elements made with thoriated glass to be thinner, and helps make them very sharp.
I’ll discuss thoriated glass in much more detail in the future, so today we’ll focus on the rest of the Kodak Signet 50.
I’m pretty sure the Signet 50 was acquired from a Goodwill auction during a brief flirtation I had with their site last winter. Sadly, it’s very hard to know what you’re getting and sometimes the prices get worse than on eBay, so I’ve mostly avoided the site since.
I can’t remember for sure what I paid, but I think the signet 50 was the camera I got on the cheap because “Kodak” was misspelled in the auction title.
Kodak Signet 50 specs
Starting at the front and going right on through to the back, the Signet 50 is full of a confusing combination of assets and liabilities.
It features a 44mm f/2.8 Ektanar lens. This is a three-element design and features anti-reflective coatings on the air-glass surfaces — a treatment Kodak calls “Lumenized,” and which started some time in the 1940s.
The fast (for its day) f/2.8 maximum aperture also stops down to f/22, and the lens is mounted in a Kodak Synchro 250 shutter. The shutter’s fastest speed, as indicated by the model number, is 1/250 sec., and it goes down to 1/4 sec., and bulb.
The Signet 50 uses scale focus — from three feet to infinity — and has zone focus markings, as well: “close ups,” “groups,” and “scenes.”
The aperture and shutter speed rings, around the lens, are mechanically coupled together. Pushing the aperture ring back toward the body decouples them, and you can adjust one or the other individually to set up a certain Exposure Value.
Once a given Exposure Value is set, both rings move together to maintain the same value while adjusting to freeze motion, or shorten the depth of field. There are red EV numbers printed around to the bottom of the lens, and depth-of-field guides on the front.
The EV numbers come into play because the Signet 50’s selenium meter reads in Exposure Values. The dial is a simple metal ring that is also the film speed setting. The edge of the ring projects from the side of the top plate and, when turned, adjusts the EV numbers on the scale as the speed is set. It supports film speeds from ASA 10 through 400.
The shutter release is a plastic “switch” projecting from the front of the camera, kind of like an inexpensive version of the metal tab on the Kodak Motormatic 35. Interestingly, the shutter has a lockout that prevents it from firing if the camera isn’t loaded with film. A number of other Kodaks in my collection from the 1930s to the 1950s feature this quirk.
I don’t always say it explicitly, but the Signet 50 is a 35mm camera. It’s even marked right on the bottom, “Use Kodak 135 film.” Loading is pretty much standard — if you don’t know the general practice of loading a 35mm camera, this video of loading film into a Kodak Retina IIIc should help.
The film advance lever is on the bottom of the camera, and just in front of it — on the very bottom of the front plate — are the frame counter and the spool release switch. The rewind knob is on the top left, and on the right edge of the camera is a tiny, recessed catch release for the film door.
The viewfinder features a brightline framing line with parallax correction marks for 3-foot and 5-foot focusing distances.
On the left side is a flash mount for the standard Kodak external flash units of the day. Kodak referred to this type of fitting, which has three sockets — one threaded, and two not — for attaching the unit, as a Kodalite mount. The flashguns available in this mounting style all take bulbs. From the manual (available in PDF from Mike Butkus’ CameraManuals.org): “The Kodak Synchro 250 Shutter synchronizes No. 5, No. 25, and M-2 lamps at speed 30 (1/30 second). Electronic flash (zero-time delay) synchronizes at all shutter speeds.”
There’s a cold shoe on the top plate, and on the back of the camera is a frame for the same Kodak Exposure Value guide cards used by the Motormatic and the Kodak Pony II. On the left-hand side of the bottom plate there is a standard tripod socket.
The body of the Signet 50 is made primarily of plastic — not Bakelite, but something more lightweight and maybe a bit more brittle. The top and bottom plates are very thin sheet aluminum.
Using the Signet
Having used enough of these old Kodaks, I’m generally able to warm up to a new one pretty quickly. Through the years, the same features have filtered down through the ranks from when they were introduced on a high-end model, until they were supplanted by an improvement or design overhaul. Thus it is that I can clearly see features that parallel those of the Pony II, the Motormatic 35, the Retina I, II and III series, and so on.
Loading the Signet 50 is easy and straightforward. The take-up spool has a very large gap and a tooth that locks into a sprocket hole on the film leader. Keeping it caught on the tooth while doing your initial advance take a little patience, but it’s nothing you can’t handle with a little persistence.
The film path is clean and flat, and as you can see, the images it produces show that. The tiny catch to open the film door might require you to leave a fingernail unclipped — it’s recessed into the aluminum plate around it and is quite small. The switch is held in the closed position by spring tension, and it’s firm but not difficult to open.
All that said, there are a few features and design cues on the Signet 50 that are firsts for me. The location of the frame counter, for example, seems exceptionally odd. The Signet cameras were designed primarily for budget-conscious market segments and I’m sure this placement was an easy solution to the problem of putting the film advance lever on the bottom of the camera.
In practice, you’re tempted to try to use your third finger to advance the film quickly, but the lever has to rotate about 180 degrees, which is too far for your fingers to comfortably manage without moving the camera quite a bit. It rapidly becomes obvious that you’re better off just turning the thing over and using your thumb, which seems to defeat any convenience that the odd placement might have initially implied — although it’s possible the placement was simply a matter of convenience after the light meter was placed on the top right.
The tiny spool release switch next to it does not seem to lock in place. In order to rewind the film, I had to hold the switch to one side the entire time. On the plus side, the rewind knob pops up above the top plate enough to make spinning it quickly quite easy. Once I figured it out, rewinding was quick and easy.
The shutter release feels cheap and plasticky, unfortunately. And in operation, it moves very smoothly — so smoothly it’s not clear where in the downstroke the shutter will actually fire. It works just fine, though.
The camera isn’t heavy, but it’s not light, either. Very similar in weight to the Pony II. And it feels reasonably solid despite seemingly being made of less-robust materials.
The zone/scale focus system seems accurate and turns smoothly. Sadly, I just sort of still hate it. I even used my Akameter accessory-shoe rangefinder for testing. Of course, an external rangefinder only measures the distance — you still have to manually transfer the distance from the rangefinder to the lens. It’s easy to forget if you’re not paying attention.
Overall, the plastic body feels solid and reliable, lightweight but not cheap. Kodak clearly made everything they felt they possibly could out of plastic, but seemed to put some real effort into choosing a solid plastic. Actually, the thin aluminum parts are about the cheapest-feeling part of the camera.
The film advance underneath the camera takes some getting used to. It advances nicely, though, without too much pressure required. In fact, it’s smooth enough to make me worry the film might not be advancing.
The meter on my Signet 50 still works just fine. In fact, I think it even reads pretty accurately — I used it for the photos in this post and most of them came out quite well exposed. I used expired Kodak Gold film that came out a bit grainy, but sharp and nicely contrasty.
The sharpness and contrast, of course, are owed entirely to the lens. You don’t buy an inexpensive, vintage Kodak 35mm camera expecting optics that compete with Zeiss and Leica lenses of the same age. But Kodak’s cameras competed mostly against Agfa, Ansco, Argus — and some companies whose names don’t start with A, too (like Spartus, Imperial and Graflex). Given that playing field, their lenses are really very capable and most are quite sharp.
I didn’t notice any significant distortion in my images, and the sharpness seems to extend right to the corners with almost no decline. I don’t see any noticeable vignetting or chromatic aberration, either. All in all, the Signet 50 is capable of taking very good images — easily a match for those from its rangefinder-equipped competitor, the Argus Match-Matic C3.
The viewfinder feels big and is really quite bright. I think the viewfinder is fairly accurate, if maybe a little conservative. The photo below, for example, seems to have more room around the edges than I left when making it. Not a lot, just a little. That’s better than the opposite, though — being a touch conservative in the viewfinder makes sure there’s room to crop and straighten the final image if necessary.
There is a strange gap in the lower right of the brightline frame that would be a good place for a meter readout, but I don’t think that’s what it’s there for. Actually I’ve no idea what it’s there for. It doesn’t appear in the manual’s illustrations, so it could just be damage or age on the part of my specific Signet 50.
The interlocking shutter speed and aperture setting rings can be quite handy when you’re using the camera in consistent lightning situations, allowing you to maintain the same Exposure Value while prioritizing speed or depth of field based on your subject.
At first it seems strange that the EV numbers on the rings are on the bottom, since you need them to use the meter. But as a long-time believer in keeping the mode dial on “M,” I like that the actual shutter speeds and apertures are up top where I can see them more easily. In a way, it feels like it might be a nod to more serious photographers, although it occurs to me that built-in light meters were still relatively uncommon when the Signet 50 was introduced and so it might be that Kodak expected some photographers to already own external light meters and be used to that workflow.
The bottom line is, the features and design of the Kodak Signet 50 might not seem completely intuitive and comfortable at first. Some of them aren’t even that great. But it’s still a very workable camera, and can take perfectly nice pictures — easily as good as its competition at the time.
Don’t get me wrong, I’ll still be sticking to my Nikons when I want a nice picture. But this guy has earned a spot on my shelf with its Streamline Moderne design and useful feature set.
Here are some more of my test images: