To obtain a photographic image good in granularity by the use of a high-sensitivity film.

A reference luminance level Lp where a diaphragm is switched by adjusting the resistance value of a variable resistor at an adjusting part is set to be higher than a middle level LM in a luminance area where subject luminance areas and which does not cause trouble in practical use to each diaphragm value, overlap. The high-sensitivity film is loaded in the unit main body of the film unit with a lens. Since the level Lp is set to be higher, photographing using n underexposure area is reduced even though influence by the reflectance of a subject is exerted, and cases where the granularity deteriorates, are decreased.