Equipment: HP5+ 400 ASA, Rollei 35
Light conditions and subject: Sunbather in grass surrounded by trees but with Sun in clouds fairly overhead, sometimes in some shadow. Bright day but with sky covered by white cloud (clouds acting like big diffuser). I'd estimate an EV between 11 and 13.
What I did: I was an idiot. Light meter showed that for 1/125 seconds I should use around f4. Sometimes it went below that to f3.5 and no higher than f5 when I dropped to 1/60 seconds. I consistently shot what the light meter recommended (only afterwards did I think that it didn't seem right for the conditions and changed the battery).
In terms of EV values I think I exposed for 9 when it should have been 11, and exposed for about 10, when it should have been 12-13.
Questions: Should I push my film? If I do, how much more grain am I likely to get?
Any other experiences, thoughts and advice are much appreciated!
Edit: I've realised that in effect what I did was pull my film from 400 to 50. Maybe someone has tried this before?