> Conversely the only time you'd be likely to encounter EV 18 on this world > would be if you photographed a nuclear explosion! :-) Even a bright summer's > day is likely to be no more than EV 13-14, so don't worry too much about it. I should withdraw the above (but not the section on EV 1). EV 18 can be defined as a situation where, using ISO 100 film, an exposure of 1/1000th sec. at F16 is achievable-blame dull UK weather for confusion!! >From Julian Loke, > The depressing thing is that Canon uses an EF 50mm f/1.4 > for the AF dark limit spec. > > If you use a slower lens, the sensor receives less light > so the dark limit is reached even earlier. > > e.g. EV 5 in front of a f/5.6 lens translates to EV 1 behind > the lens at the AF sensor. > > According to my calculations, the EV 1 AF dark limit is reached > whenever the meter says Tv=1" @ ASA=100 for ANY lens wide open. > Or Tv=1/2s @ ASA=200, or Tv=1/4s @ ASA=400 ... you get the idea. Thanks Julian, you saved me some typing! :-) Possibly for the EOS 3 Canon may have used 50mmf/1 to measure EV 0 (1 sec. at F1 with ISO 100)? * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
