Marko: An intriguing problem. Re the term F-stop or f-stop, I did a quick scan of my two Pentax and Nikon manuals and they do not seem to use the term very much actually they seem to shy away from it. Maybe to hard to explain in the world of seamless f-stops. Anyway what I wonder is, would the average person who would benefit from your book even know his camera has them. Re the innuendo titles, suggest you take care not to turn off a market segment. If we were back in the film days I could see your F-stop title and superb background photo being of interest to someone who may have bought a photo mag or two - in other words some one who knows he/she doesn't know stuff. Comments hopefully meant to help, not irritate - been down the editing lane, it can be s....y.