As for working on your reciprocity, consider this first. Due to the low light situation, getting an exposure wrong is harder to do than you may think. There is a lot of latitude in the exposure. Way more than in lensed photography. Next, get your hands on the program "Pinhole Designer" http://www.pinhole.cz/ if you have Windows. You can use that program not only to design a pinhole camera but also to generate a table of exposures on the basis of f22 measurement with your light meter. Oh man, that program is very nifty. Too bad they don't add more films to the database, but most of the films today are near 100% matches for the films that are in that database, so you just have to know what you're looking for, but this is a great little program and I rely on the charts I have made from it. I just measure for f22 always, then get my time, then look on my chart, bingo. It's a go. the lower the light, the more the latitude. late afternoon shots look the same if it's a 10 second or 15 second exposure. That's the kind of latitude there is, when you have the right reciprocity and this program will help you achieve that.