Here’s a quick thought that jumped off from my earlier posting about camera design: It's interesting to note that the thumbwheel idea of a shutter control seems relatively recent. F, FE, FM, FA, F3, even F4 I think, as well as Pentax Spotmatics and almost everybody pre-1980 all have a knob you have to grip and sometimes even pull up first with thumb and forefinger of right hand to adjust the shutter-speed. I’m a little clumsy (and I panic and make mistakes when I’m trying to grab a quick shot of something that’s disappearing or losing it’s naturally great composition fast), so personally I find this arrangement inconvenient. I wonder, could the much more user-friendly single thumb or forefinger-stroke operation of the shutter-speed dial be a reflection of improved film-speeds allowing increased popular emphasis on action photography, sports and war-zone reporting, plus the fact that the actual selected shooting speed could be shown in the viewfinder from the 1980s onward. Apart from war-zone and sports photography, picture-taking previous to 1970 was a more relaxed affair, with more formal poses allowing more time for the photographer to adjust his camera settings, therefore, a viewfinder setting display and one-finger control of shutter speed wasn't so necessary? Could that be it?) Tube.