Ideally, you never use the internal filter.
Much better to use appropriate screw-on filters on the lens, if possible. Why's that? Any given Super-8 camera is (at least a few) decades old and the cheap piece of orange plastic in there could be beat to hell and back. Warped, faded, cracked, whatever.
Currently, all Kodak S8 film is tungsten based.
If shooting any of the b/w stocks, there is no "filter notch", so the internal filter will always get switched on (if the camera recognises these notches) Doesn't really matter about colour balance here, as it's b/w. Even so, would be nice to be able to switch it off.
If shooting colour (64T, 200T, 500T), there is a notch on the film cartridge. With that notch, there is no hard plate for the pin inside the camera to hit against... so you can manually adjust that "bulb/sun" switch all you want.
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Keeping in mind that all current colour Kodak stock is made for tungsten lighting...
If you are shooting outdoors in daylight, you want an orange (85) filter on. Either the internal one (move switch to "sun" icon), or add your own at the end of the lens.
If you are shooting outdoors at night... it depends on what your illumination sources are. Your usable light could be tungsten or daylight oriented. Heck, whenever I rent a set of Kinos I always get tubes balanced both ways, so I can swap them out for what is appropriate.
If you are shooting indoors... what is your main source of light? If it's the tungstens overhead, filter off. If it's a tonne of daylight pouring in through open windows, filter on. If it mainly daylight, with some help from the tungsten overheads, time to gel the interior lights. Mixed light temperatures suck.
For indoors, you'd even need to take a look at the actual bulbs in their sockets. My ghetto light-kit has replacement bulbs in regular tungsten, and also a stash of daylight-balanced socket bulbs (very cheap at K-Mart, wherever) to use inside when outside daylight is the main source.
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It can, of course, be easily color corrected digitally
Arrrgh! Fix it in post?!
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Finally! Getting to address the specific questions...
It was an overcast day, and I cant remember if I was using the daylight filter. I'm going to say no
That sounds right to me. Tungsten film shot in daylight, with no orange filter, will look bluish.
I also noticed the bluish tent when indoors with bright lighting
Harder Q. Was it a lot of sunlight coming through windows? You have non-tungsten bulbs in the light sockets? (or daylight-coloured tungsten ones?) Did the previous owner of your camera remove the internal filter? (Not as crazy as it sounds)
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It's a lot easier these days with video cameras. Every man & their dog knows how to operate the "Set White Balance" button. But back in the day...
p.s. Find a good colour temp chart.