Lightweight blazer, chambray shirt, chinos and a pair of Sloops. That is the proper version of the California tuxedo, worn in the photo by Luca Cordero di Montezemolo. An ensemble for casual days in the spring sunshine, it is perhaps appropriate at the track (autos, not horses) as well as certain wineries and smaller towns where there are no neckties within a minimum of twenty miles. The blazer should be single breasted, and patch pocketed, and the shirt ideally a white or blue buttondown with the collar left flapping.
The informal version of the California tuxedo substitutes Japanese denim trousers for the chinos and may be worn with a polo instead of a conventional shirt but only with caution as the polo may be a step too far. That is because, though relaxed, the proper California tuxedo demonstrates that the wearer is not an ordinary man. For though his clothing may appear approachable at first glance, the blazer and chinos should be hand sewn in a small Neapolitan atelier, and the shoes from an obscure source. The shirt may be off the rack from Brooks Brothers or the like as a statement that the wearer is a man of the people but then there will be all that extra cloth ruining the look. Better to have it carefully tailored to appear ready to wear.