The testing of photographic lenses

The Eye and Photographic Lenses.

It appeared incomplete but formed a considerable segment of a circle. The above description applies chiefly to -the left iris. The departure from the normal. was less marked in the right eye. The writer believes this to be a case of congenital miosis of varying degree in the two eyes, and due probably, having regard to the findings of Holth and Berner, to developmental faults in the dilator mus...

Sources of Error in and Calibration of the /-Number of Photographic Lenses

In problems of photography, where the accuracy of lens marking is critical in determining the proper exposure, the various errors to which these markings are subject is of considerable interest. The present report gives the magnitude of such errors that were found to exist in a representative group of 20 lenses having focal lengths that range from 0.5 to 47.5 iii. In addition, the results of ca...

Design, Fabrication and Testing of Kinoform Lenses

INTRODUCTION Fresnel lenses are a type of lens that eliminates the bulk of a conventional lens by collapsing the lens thickness while retaining the curvature necessary for focusing. Figure 1 shows the Fresnel lens equivalent of a conventional lens. For a rotationally symmetric lens, the discontinuities or grooves formed when collapsing the lens are annular. This produces a much thinner lens, pa...

Testing for the impact resistance of ophthalmic lenses

the effect of taftan pozzolan on the compressive strength of concrete in the environmental conditions of oman sea (chabahar port)

cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...