Outing . the better types of foldinghand cameras like the. Kodaks, Anscos,Premos, are regularly equipped withrapid rectilinear lenses, though any ofthese may be had with anastigmat lenses,and the specials are always fitted withthem. These are the slow anastig- that you have this reserve speed for useif necessary; but because of their bulkand lack of depth, which makes it nearlyimpossible to guess at the focus, they arenot suitable for hand-cameras. The rapid rectilinear lacks the speednecessary for making photographs in dulllight, or faster than about 1-100 of a sec-ond in the best light. If o
Outing . the better types of foldinghand cameras like the. Kodaks, Anscos,Premos, are regularly equipped withrapid rectilinear lenses, though any ofthese may be had with anastigmat lenses,and the specials are always fitted withthem. These are the slow anastig- that you have this reserve speed for useif necessary; but because of their bulkand lack of depth, which makes it nearlyimpossible to guess at the focus, they arenot suitable for hand-cameras. The rapid rectilinear lacks the speednecessary for making photographs in dulllight, or faster than about 1-100 of a sec-ond in the best light. If one might al-ways choose the conditions for picturemaking, a lens of this type could be madeto answer, but unfortunately this is notpossible. Other faults of the rapid recti-linear are lack of covering power, whichmeans that the corners of the picturesare blurred and under-exposed, and lackof definition, which means that the imagehas not the needle-like snap and bril-liancy that an anastigmat will A GRAFLEX EQUIPPED WITH A HOME-MADE MAKE-SHIFT EXTENSION CORE FOR THE USE OF LONG FOCUS LENSES—BUT IT WORKS ! AS ILLUSTRATED—EQUIPPED WITH FRONT COMBINATION (24 INCH FOCUS) OF A 12-INCH CONVERTIBLE ANASTIGMAT mats, none of them working faster To get the full value of its speed, theultra-fast lens of this type, with its aper-ture of F , is only suitable for use onthe reflecting cameras, both on accountof its large size and also because of itslack of depth of field, which requiresvery careful focusing when the lens isused wide open. Stopped down, ofcourse, to F 8 or F 11, or what you will,one obtains the same depth and the samespeed as with any other lens used at cor-responding openings. The real advan-tage of these ultra-fast lenses is the fact Technically this is caused by astigma-tism, and in plain terms means that thislens is not corrected to cause the raysof light from the object to converge intosharp points upon the plate. Comparing a photograph made with
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Keywords: ., bookcentury1800, bookdecade, booksubjectsports, booksubjecttravel
