It goes without saying that when you set off on your travels you pack clean clothes, toiletries and other essentials – such as headache tablets – into your chosen luggage type. But, to get the most out of your time on the move on in your hotel, what else should you take with you? [...]

What does the iphone has to do with photography? There’s a neet utility for us photographers who have an iphone or ipod. 
It’s PhotoCalc which can calculate depth of field and hyper-focal distance as well as flash exposure and exposure reciprocation.
Here’s some of PhotoCalc’s features:

    * Exposure Reciprocation calculator
    * Depth of Field (DoF) and Hyper-focal Distance [...]