I realize that this is something of an oxymoron -- consumer digital sensor and ISO -- and but perhaps someone can shed some light. In some recent, very casual tests, I took a look at recording in ordinary room light conditions, both without any gain and with 3,6, and 9. Using my Luna-Pro and setting the camera's max aperture to see what shutter speed would be needed, it appeared to me that, at 1/60, the sensor's effective ISO without gain lies somewhere in the realm of ISO 100. I am just curious to know if this conforms to the expected.

My interest is mainly for interviews I do as a one-man crew. I travel with light and sound kits each packed into rolling backpacks, as well as, of course, stands, stingers, and modifiers. The light kit has Tota, Omni (both 500W) and Pro-Light for a backlight, which suffice. But on one occasion, when I was in a very tight space in an apartment, I used just a pair of 85-watt CFLs and was a little surprised when, hung behind a fabric diffuser, with some silver lame behind them to bounce more light forward, to make a big soft light from just about 3 ft., I was barely making exposure without gain, or perhaps I added 3; I don't recall.

ISO/ASA 100 equivalent is not out of the range of possibility, although I have seen numbers closer to 300 mentioned for typical digital camcorders. Film speeds are typically set based on producing a specified range of image density with specified processing (chemistry, time, and temperature).

As you noted, ISO is not normally defined for video camcorders as it is for film. The typical specification is a f-stop and illumination level (e.g., 2000 lux at f/8). The camcorder gives immediate feedback on exposure in the video signal (on the monitor) - no need to wait and process the film to see if you got the exposure right. But a light meter can help when lighting a set without the video camera present.

Consumer camcorders often speak to a minimum light level in lux, but generally do not clearly define how they arrived at the number; (e.g., not specifying the shutter, aperture, gain, reflectance of the target and resulting video IRE and noise levels).

...it appeared to me that, at 1/60, the sensor's effective ISO without gain lies somewhere in the realm of ISO 100. I am just curious to know if this conforms to the expected.

I've got an HSF200. My experience matches yours reasonably closely. It might be ISO 200, but I'm pretty sure it's not as high as ISO 400. It's got a tiny sensor and it's several generations back; no reason to expect it to be a good low light performer.

Thank you, gentlemen. I worked with film for decades as a still photographer and performed more film and development tests than I can remember, from 35 mm to 4x5; my video efforts are still amateurish, benefiting mostly from my accumulated lighting skills. I keep studying as I can. Perhaps one day I'll have reason to justify investing in equipment that will bring a larger sensor and its optical correlates to bear.