Quote Originally Posted by David Henderson View Post
I spent a whole day photographing there on an overcast day last October. I just checked through my settings. ISO 1600, f4-f9.5 with probably f8 being the commonest; 1/15 handheld with IS. Even at these settings I'm exposing dark rather than light. The issue isn't helped by the fact that to get other than bland wide-angle shots you need a longish lens and so depth of field isn't something that you can forget about. I was using pretty much the same settings in pit 1- where the volume is- and in the glass cases/other pits.

Based on this I couldn't possibly suggest that you will be OK with ISO400 film. You either need something faster or hope for more ambient light getting into the pits. I did see a Chinese guy photographing with a tripod but it was quite a quiet day, and for all I know he got pounced upon by the guards right after I saw him. Probably wouldn't be physically tenable on a busy day anyway.
Based on what you have said, it sounds like 400 film is fine if one does not use f/8. I certainly would not expect to be able to use f/8 there with a 400 film. As always, photography is a balancing act. What is more important to you? Depth of field, or the qualities of a slower film?

Whatever the choice you make is, it would certainly seem prudent to bring fast fixed-length lenses instead of zooms, as it is obviously a place with somewhat-low light levels. 50 1.4, 85 1.4 or 1.8, 100 f/2 or 105 f/2.5, etc.