I can't answer the question exactly, but in "the old days" light was measured in "candela", which is the light from one candle:
Definition: The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian. The frequency chosen is that to which the eye is most sensitive. This frequency is normally referred to as the corresponding wavelength: 555 nanometer. The wavelength varies with the medium through which the light passes, so, in the interest of precision, our relatively familiar wavelength description of light is not used in the standard. The strange choice of the number 683 is to make the value identical to that obtained with the previous version of the unit: the emission from 1 square centimeter of glowing, solidifying platinum. The steradian is the cone of light spreading out from the source which would illuminate one square meter of the inner surface of a sphere of 1 m radius around the source. Read more at: http://www.electro-optical.com/whitepapers/candela.htm All the best Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -----Oprindelig meddelelse----- Fra: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sendt: 24. august 2004 17:32 Til: [EMAIL PROTECTED] Emne: Re: AF problems with *ISTD! Mr Robb posted: > Pentax sez the istD AF sensitivity goes to EV 0, while the MZ-S goes > to -1. > Thats a full stop less sensitivity on the istD, which will certainly > be noticable. > OTOH, digital cameras are next to useless below EV 1 (my situation, > YMMV). What's the EV number relating to the light of a single candle? I ask because that was the light source on this image autofocused and taken by my Optio 550 (I remember it was autofocus 'cause there's No Way I could have manually focused it; too dark) http://members.aol.com/greenfalc1/2004wk10.jpg Haven't tried something like that with the *istD, yet; but I think I've mentioned before that I use manual focus more than autofocus with it; seems I can focus faster than the camera can. ERN
