PhotoCalc

If you have an iPhone, you should take a look at PhotoCalc, a program developed by Adair Systems, LLC. The feature I use the most is the Solar Calculator which will tell you sunrise & sunset times at wherever you are (or for any other location you enter). Another feature that may be helpful is the Depth of Field Calculator. Enter the focal length of the lens, the f/stop, & subject distance and it will show the depth of field; somewhat useful since most DSLR lenses no longer show this. Other features include a Flash Exposure Calculator, Exposure Reciprocation, and a number of other reference items. The cost is $2.99 from the iTunes Store.