where can I get one of the reversing prisms?I think that would be way more handy than a mirror. Thanks again for the great advice.
Matthew,It is a lot handier than a mirror, especially in the field. Plus you can look at your painting and your motif upside down, which can be a handy way to shake up your thinking.I bought my prism at a local science supply store. It is just a standard prism. Some novelty shops might have them as well.
Thanks for your comments!