The very first daguerreotype cameras could not be used for portraiture, as the exposure time required would have been too long. The cameras were fitted with Chevalier lenses which were "slow" (about f/14). They projected a sharp and undistorted but dim image onto the plate. Such a lens was necessary in order to produce the highly detailed results which had elicited so much astonishment and praise when daguerreotypes were first exhibited, results which the purchasers of daguerreotype equipment expected to achieve,Using this lens and the original sensitizing method, an exposure of several minutes was required to photograph even a very brightly sunlit scene. A much "faster" lens could have been provided—simply omitting the integral fixed diaphragm from the Chevalier lens would have increased its working aperture to about f/4.7 and reduced the exposure time by nearly 90 percent—but because of the existing state of lens design the much shorter exposure would have been at the cost of a peripherally distorted and very much less clear image. With uncommon exceptions, daguerreotypes made before 1841 were of static subjects such as landscapes, buildings, monuments, statuary, and still life arrangements. Attempts at portrait photography with the Chevalier lens required the sitter to face into the sun for several minutes while trying to remain motionless and look pleasant, usually producing repulsive and unflattering results.