There are numerous times when I am carrying around a fairly bulky digital camera that I don't intend to shoot photos on, particularly if I am shooting subjects for which I'd rather use film as my medium. Sometimes I can get around this by using the "Sunny 16 Rule" but when shooting transparency film, a miscalculation of the degree of overcast may wind up resulting in an over or underexposure beyond what the film can handle. Similarly, I have a light meter app that works well, but can be prone to glare on the screen. As well, I have seen my phone itself reset the calibration of this app on one occasion, so I can't quite trust it without worry.
Thus, the Olympus PEN has been a fairly regular staple in my small camera bag, even if I don't intend on taking photos with it. I generally trust the readings I get from it to provide me enough accuracy to shoot transparency film using its settings. Aside from the bulk of it however, it has additional hiccups as well. I can not set the ISO rating below 200. Thus, if I am shooting Provia 100, Velvia 50, Retro 80S, or RPX 25, I have to do a number of quick calculations on the fly to determine exposure based upon the readings for ISO 200. Also, the PEN obviously runs on batteries, and there are times when I have to take my readings quickly when the battery is mostly depleted. And if it does crap out, I am out of luck until I can charge it - and I still have to carry around its bulk.
How nice would it be if there was an affordable and compact way to take accurate exposure readings for even the slowest speed films that did not depend on batteries. The cynic in me would expect this to be an absolute impossibility. That cynic has since been proven wrong. Meet the Gossen Sixtomat!
Clad in ivory and trimmed in gold, the mid-century appearance of the Sixtomat is hardly what I would call contemporary, but therein, I hardly consider it to be a fashion accessory, and more of a tool. But that's not to say that this little device isn't fascinating in its design. Quite the contrary. The Sixtomat shows a clear degree of simplicity, easy form factor, and sensible layout and readings. Have a look!
Usage of this 1950's classic is a breeze. One simply rotates the dial on the side (seen above) until it starts clicking in either direction to dial in your ISO/ASA speed. Settings range from 5 to 200, perfect for slower speed films or even expired emulsions in which you wish to use a lower EI on the expectation of lessened sensitivity to light. Then (with roller blind retracted), point the meter in a downward direction at the subject you are facing, rotate the same speed dial to where the needle on the front BISECTS the sideways "X" that is in the lower window on the front, and Voila! You've got exposure readings on the top. Explanation aside, this is more easily compared with the photo at the top.
One thing I love about the Sixtomat is the dual scale for shutter speeds. The bottom row of green numbers correlates to newer shutters on slow speeds with 1/4, 1/8, 1/16 etc, so that it works well with the camera on the left. Meanwhile, the top set of readings uses shutter readings common to older shutters such as Compurs. Note the readings for 1/5, 1/10. and 1/25 that line up with those on the other camera.
The form factor is easily pocketable, and includes a less than contemporary "gold" chain for carrying. In addtion, the Sixtomat can operate as in incident light meter rather than a reflected light meter by dialing back the blinds to the red marks, as can be seen above, Then the meter is pointed upward to get an incident light reading.
The Sixtomat also includes a rudimentary light temperature reading. Pretty neat, but admittedly beyond my needs.
When purchasing a 50-60 year old Selenium Light Meter (or even one using obsolete batteries), on muse be very mindful of working condition. All too often, the selenium cells or contacts will oxidize killing their sensitivity to light. However, when found in working condition, these meters make a great alternative to expensive digital meters, smartphone apps, or lugging around a metered camera that will not be used!
And if you don't fully trust an old meter like this, maybe consider buying two. Thus, you can have "Six in One Hand and Half a Dozen in the Other!"