Turtle
Veteran
If 1/3 of a stop never matters to you, you would appear to be consistently overexposing and so can afford to lose it 🙂
I find myself very mobile in EI too, but it depends not only on the light but how I am able to do the metering. If I am not able to reliabily meter shadows I will set a much lower thena normal film speed if I am in bright contrastyn light - maybe 200 and work from there, but as soon as I hit a good shadow to work from, I will use 400 to determine whether that leaves me.
My conclusion is that there is no simple rule, only a good understanding of light and your materials...
I find myself very mobile in EI too, but it depends not only on the light but how I am able to do the metering. If I am not able to reliabily meter shadows I will set a much lower thena normal film speed if I am in bright contrastyn light - maybe 200 and work from there, but as soon as I hit a good shadow to work from, I will use 400 to determine whether that leaves me.
My conclusion is that there is no simple rule, only a good understanding of light and your materials...