Transactions of the Society of Motion Picture Engineers (1916)

Record Details:

Something wrong or inaccurate about this page? Let us Know!

Thanks for helping us continually improve the quality of the Lantern search engine for all of our users! We have millions of scanned pages, so user reports are incredibly helpful for us to identify places where we can improve and update the metadata.

Please describe the issue below, and click "Submit" to send your comments to our team! If you'd prefer, you can also send us an email to mhdl@commarts.wisc.edu with your comments.




We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.

Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.

glass and upon the angle of incidence under which a ray strikes the surface. It increases, therefore, towards the margin of the condenser because the angles of incidence are greater there than nearer the center of the lens. The following two tables show for 4 different zones of an ordinary M.P. condenser, the path lengths and the mean losses by absorption and refraction in these zones for the absorption coefficients 1.3% and 3.9% per cm., which are about the limit values for glasses available for this purpose. Figure 12 illustrates approximately the paths of the rays representing the middle of the zones through the condenser. SPHERICAL DOUBLE CONDENSER Absorption Coefficient 1.3% per cm. Distanceof Loss in % by ab 1 Sum Loss center of Loss in % by reflection sorption and of zone from on surface length of path in losses J" /o opt. axis lens in (mm) 0/ /o m zone I 2 3 4 I (22.5) II (19.4) 5 4-4 4-1 3.9 3.6 2.7 (21.7) 2. 1 (18.0) 20.8 1-3 15 4-4 4-1 3-9 3-6 2.6 (18.4) 1-9 (15-0) 20.5 3-9 25 4-4 4-2 4.0 3-7 2-3 (14.9) 1.6 ( 9-7) 20.2 6.3 35 4.8 4.5 4-2 4.0 1-9 I . I 20.5 9.0 Total Loss 20.5% Absorption Coefficient 3.9% per cm. Distanceof center of zone from opt. axis Loss in % by ab ! Sum Loss in % by reflection sorption and of on surface length of path in lens in (mm) losses % Loss in zone I 2 3 4 I (22.5) II (19.4) 5 4-2 3.8 3-7 3-3 8.2 (21.0) 5-9 (18.0) 29.3 1.8 15 4-4 3-8 3-7 3-3 7-7 (18.4) 5-5 (15.0) 28.4 5-3 25 4-4 3-9 3-8 3-5 6.9 (14.9) 4-7 ( 9.7) 27.2 8.5 35 4.8 4-3 4-1 3-7 5-5 3-2 25.6 II .2 Total Loss 26. The same is done in the next two tables for a Fresnel lens, which is spherically corrected, has only 2 reflecting surfaces, less glass path, but higher angles of incidence in the outer zones. The average glass path is here the same for all zones and equals 10 mm. 55