I have a few older cameras (Arettes and Voigtlanders) that have a non-selectable section of the shutter speed scale in green. It typically goes; 4, 8, 15, 30, 60. I understand the purpose of this scale was to remind the user of slow speed steps: that two times 4 was 8, and so on. However, I don't understand why 1 and 2 were missing - in fact, I don't understand why the scale was felt to be necessary at all?
Does anyone have an insight as to why some manufacturers thought this "feature" was useful?
If these are non-selectable, they should not be shutter speeds. Non-selectable shutter speeds would be an oxymoron. Back in the old times people learnt multiplication tables, and the "2" one was easy. Therefore I do not believe this is an arithmetical reminder.
Maybe if you post an image we may be able to collectively guess what those green figures are.
Some Japanese RF used green figures for guide numbers, in their Flashmatic systems. I have a Minolta, an Olympus and IIRC a Canonet that feature green guide numbers. But 4 would be way too low a guide number, even in meters. So there. Mistery.
Last Edit: Sept 6, 2016 20:20:57 GMT -5 by julio1fer
Are these not shutter speeds in full seconds and would give you a B setting like here? I think that you would have to count the exposure seconds manually. I think that they are there because of the built in light meter.
Julio1fer - yes non-selectable shutter speeds is my deliberate oxymoron used to describe the paradox of a shutter speed dial with "values" that cannot be selected, but that's exactly what they are: a scale of incremental, whole seconds, shutter speed steps beyond the travel of the shutter speed dial. They are however not a reminder, but rather an instruction.
Rachel - yes you are on the right lines in that "green" times are invoked via a B setting and a manual count of seconds. Their purpose is however nothing to do with a built in light meter, because the large viewfinder Vito B, and Arette Super P don't have light meters. But, you did cause me to think about what these two cameras and the others (light meter equipped Voigtlander BL and Arette 1Dn with the green scale) have in common, from which I spotted the answer.
And the answer is - they all have an EV scale. The shutter speed values are not selectable, but they do register against an aperture setting when read in the correct way - in the manner of a slide rule.
If you work-out an exposure in EV values (which I personally have never done), then their purpose is intended for exposures at EVs 2 to 6. With the shutter speed dial set to B, the green figures align with the required aperture settings (e.g. at EV 3, f/5.6 at 4 seconds, f/8 at 8 seconds, etc.).
The reason why "1" is missing from the scale is that I failed to recognise (with an "s" because I'm English) all these models have a slow speed of 1 second (derrrr!!!!).
The reason why "2" is missing is because "B" represents 2 seconds (e.g. the scale reads f/2.8 at 1 sec, f/4 at B, f/5.6 at 4 sec, etc.).
At higher EVs, the green scale works only partially, as can be seen in the photo (f/11 at 1 sec, f/16 at B, f/22 at 4 sec).