Mac wrote:
My Nikon Df has a base ISO of 100, but the ISO dial allows me to go below below 100 in 1/3 increments to LO1. From what I've read online I think that LO1 would be one stop below the base ISO, which would make LO1 ISO 50. But if that is the case why is it marked LO1 and not 50?
Also are there any negative effects to IQ in shooting below the base ISO?
See page 71 in the User’s Manual. Rather than degrading the IQ, the bit of increased contrast at ISO 50 (Lo 1) is often a plus.