The Optical Magic Lantern Journal (October 1892)

113 The Optical Magic Lantern Journal and Photographic Enlarger. The question next arises, how is it to be tested for flatness of field. It is not sufficient that a photographie transparency be employed for the purpose, although it has been advocated that a good means of testing is to transfer an ordinary engraving to glass, by causing it to adhere to its surface, and then rubbing away the paper from the back, until it becomes transparent, and using this as a slide. But by far the best method is a slide recently made and introduced by Mr. C. Goodwin Norton. He inserts in front of the condenser, a test slide, formed by a piece of Brussels net tightly stretched between two thicknesses of glass. With a slide thus formed, we are enabled to ascertain if the lens wfll give absolute sharpness up to the edges of the slide. By projecting this in the usual manner, one is able to judge at a glance the capabilities of his lens for projecting pictures with flatness of field. ——:0:—-——_ Hand-Cameras for Obtaining Slides for the Lantern. “ Pacile” .. (Fallowfield) . see March 1st,1890 No. 1 “Giah” .. .. (Mawson & Swan) +» 9 May = Ist, » 2 Quadrant” .. (W.H. Humphries &Co.) ,, June Ist, ,, » 3 “Eclipse” .. (J. FP, Shew & Co.)-. -. 4, July Ast, ,, » 4‘ Bureka” .. (W.W. Rouch & Co.) .. 4, Aug. Ist, 4, » 72 “Key” .. (Platinotype Co.) .. .. ., Sept. Ist, ,, » 6 “Optimus” .. (Perken, Son& Rayment) ,, Oct, Ist, ;, » 7 The Griffin” (Griffin & Sons, Limited) ,, Nov. 1st, |, » 8 “The Swinden-Earp” Patent «+ 5, Dec. Ist, ., » 9 “Collins” . (C.G. Collins)... .. -. 5, Feb. Ist, 1891. » 10 ‘* Kodak” .. (Eastman Co,).. --5, Mar. Ist, ,, » ll Guinea ” .. (Walter Griffith) .. .. ,, April Ist, ,, », 12 “Vanneck” .. (Watson & Sons) .. .. ,, May Ist, . », 13 “Chadwicks” (W.I.Chadwiek) .. .. , June Ist, ., » 1£ Bonanza” .. (R.&A J.Mercer).. .. ,, July Ist, ;, » 15 “Repeater” .. (J. F. Shew & Co.) +. 9, Aug. Ist. ,, s» 16 “ Marvel” .. (Wilson & Son).. » Sept. Ist. ,, » 17 “ Talmer” .. (Talbot & Eamer) .. .. ,, Uct. Ist, ,, » 18 “The Omnigraph” (J. Lancaster & Son) ,, Nov. Ist, ,, » 19 “Ubique .. (Perken, Son & Rayment) ,, May Ist, 1892. » 20 “Daylight Kodak” (Eastman Company) ,, June Ist, ,, » 21 “The Radial” (Marion & Co.) -. .. », July lst, ,, » 22 “The Surprise” (Levi & Co.) +. .. 4, Augustlst, ,, » 23 “Perfect” .. (W.Tylar).. .. -. .. ,, Sept. Ist, 5, No. 24 ‘‘ FRENA.” Tar ‘“Frena” hand camera, which has been introduced by Messrs. R. and J. Beck, Cornhill, E.C., is totally different in action to any camera which we have hitherto tried. It measures 84x44 6tin., is supplied with finder, shutter for various rapidities of exposure, film changer, and swing back arrangement. The films for this camera are put up in packets of 40 each, and are of a peculiar form. Between each film is a piece of thin and stiff ; | pointed slightly upwards, the handle may be cardboard of the same general pattern as the film (see figs. 1 and 2). The packet containing the film and cards is placed into a reservoir inside of the camera, in which they rest on teeth; when the first one will be opposite the lens ready for exposure. The reservoir is held on pivots inside of the camera, and is connected with a handle outside. To change a film after exposure, the spring f, Fig. 8, is liberated, and the handle /1, moved backwards; this causes the teeth on which the film rests, to move slightly to one side, and Film. Vig. 1. Card. Fig. 2. the film to fall, and as soon as the handle is carried a little beyond the projection m, the card also is displaced. Upon the handle being brought back to its normal state, another film is ready for exposure. This is repeated until the 40 films have all been exposed. After exposure, the films with their cards can be taken out of a reservoir below, in which they have been automatically kept from shifting. As each film is changed, its number is indicated by the appearance of a figure at 7. On the upper part of the changing handle or lever is a level, J. This not only enables one to ascertain if the camera itself is level, but it also Pog. 3. acts the part of a swing back. If the camera be pushed forward, when the level will indicate when the sensitive surface is vertical. This device will be found particularly useful. The camera has a finder and a RR lens. Respecting this latter, nothing need be said, excepting thai it is made by this firm, who enjoy