The “easiest and most ubiquitous way to get stuff out of your head is pen and paper.”
“… A paper notebook… is a walled garden, free from detours (except doodling), and requiring no learning curve.
“A growing body of research supports the idea that taking notes works better on paper than on laptops, in terms of comprehension, memorization, and other cognitive benefits.
Source: Why Startups Love Moleskines, New Yorker
Or put another way, sketch and make notes in your sketchbook, don’t only take reference photos.
In my young days I got a professional training in photography art. So I am able to build a scene automatically when driving at a speed of 160 km per hour, getting over 1000 reference photos during a day trip. Laptop then permit me to select the best and to analyze, process and/or combine them in order to use as a reference image. I use notebook whenever I have no possibility to use a cam. For example in a plain or in airport. I used my sketches for pictures may be once or tvice,so it is more for a long-term planning for the projects that hardly ever to be realized.