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July 13, 1883.] THE PHOTOGRAPHIC NEWS 435 limit of angle may easily be laid down. What we noticed in connection with this matter is, that amongst the photo graphers at the Club there was expressed an almost, if not quite unanimous, opinion in favour of limiting the angle to a much smaller one than has been fashionable, or at least customary, during recent years. We are particularly pleased to note this tendency, as we have for several years past persistently urged the advan tages of limiting the angle to such a one as is taken in by the eye at one time, and of avoiding anything greater except when this is quite impossible. The discussion was opened on this point by Mr. G. F. Williams, who said that, when he first commenced instan taneous work, his desire was to find a lens which would permit him to use an angle of 60°, or nearly so, and that he found it in the portable symmetrical. Since then, however, his tendency had been all towards the use of a lens of longer focus; until now he used one whose focal length was half as long again as his plate, instead of only about the same length as at first. Mr. Mawdesley described very graphically what must, we believe, have been the feelings of many a photographer as he advanced in his art. He said that when he was a beginner, or at least at an early stage in his photographic career, his tendency and desire when he looked at the image on the ground glass was always to get in " just a little bit more,” and he told how disappointing he found the pictures which resulted from giving effect to this desire. He then went on to say how that he discovered his error to be that he was taking in too much angle, and that his tendency since then had been to use lenses of longer and larger focus ; until now he had a distinct and somewhat confined maximum angle which he never overstepped except on very special occasions, whilst his minimum was only limited by the length of his camera. Another member stated that he worked 12 by 10 plates ; that his first lens had been of 12-inch focus; that since then he had adopted for general work a 16-inch focus, and frequently used one combination of his 12-inch lens, thus having a focus of 24 inches ; and that now he was having an adapter made for his camera to enable him to use one of the combinations of his 16-inch lens, and thus have a focus of 32 inches. All this we consider a decided and noteworthy indica tion of a movement in the right direction. With regard to the special type of lens to be used for instantaneous work, there were not found wanting advocates for every possible form of instrument, from the portrait lens to the single achromatic lens. A lens of the last de scription, and of a very old make—that, we believe, of the late Mr. A. Ross—was shown, and was said to work admirably through a moderate angle with an aperture of “ 8 ” of the standard numbers, or about Yr. One point appeared to be overlooked in connection with the discussions on the angle included by different lenses—namely, that lenses of the same type, but of differ ent lengths of focus, do not, by any means, work sharp through the same angle. A lens of long focus always works sharp through a less angle than one of short focus, and of the same type. The portrait lens, when of very short focus - say, up to seven or eight inches (equivalent)—covers through an angle which makes itquite serviceable for landscape works, and, in fact, for many instantaneous subjects, it is the best lens which can be used. A long focus portrait lens —say one of twenty inches—will, on the other hand, cover sufficiently sharply for landscape work only an angle of a few degrees. Lenses of the rapid type, and of short focus, may be worked through an angle of about forty-five degrees full aperture, and give very satisfactory results. Those of long focus—sixteen or twenty inches—will only work sharp through about 25% The portable symmetrical of a few inches focus will cover through 60° at ’ . Of long focus it will only cover about 45° with the same aperture. Another difficulty which makes itself evident when long focus lenses are used for instantaneous work, is the want of depth of focus. With a short focus lens, the depth of focus need seldom be a consideration. We are limited in the aperture which we may use only by requirements of definition and of flatness of field. It is quite different with lenses of long focus. When, for example, we get up to a focal length of sixteen or twenty inches, we will find that, entirely apart from absolute definition or covering power, it is seldom that we can use anything like the full aperture of a rapid lens, because of the want of depth of focus. For most subjects we find ourselves limited to an aperture of about or 4. The depth of focus of lenses of the same type—or, rather, leaving type altogether out of the question—of lenses having the same relation of aperture to focal length, varies inversely as the square of the focal length. For example, by doubling the focal length, we decrease the depth of focus by four times. By tripling the focal length, we de crease at nine times, and so on. All this tends to show that there are many advantages to be looked for in the production of small negatives, and the subsequent enlarge ment of them, if the difficulties attending such a process can be overcome. THE TOURIST PHOTOGRAPHER. No. 1—YORKSIIEE. Yorkshire does not receive justice at the hands of the tourist. The beauties of Wensleydale, Wharfedale, and Teesdale, to mention three charming valleys in this wide county, are rarely visited by the holiday maker, who will find here rustic pictures and green panoramas in plenty to delight him. And it is not only for leafy hills and verdant pasture land that Yorkshire is pre-eminent. Its vast moor lands and stretches of purple heather are not less attrac tive, especially to dwellers in large towns ; indeed a tramp over these breezy uplands is the most healthful and in vigorating of exercises. For the camera there are water falls, historical ruins, and village pictures in profusion, especially if it is carried by pedestrians; and it is the doings of a little party of this nature we are now about to describe. Our starting point is Leyburn, easily reached by rail from York, and here we adjust knapsacks, eager to begin. But there is no necessity for putting them on just now. Several excursions into Wensleydale may be made from Leyburn, and the first will naturally be to the Shawl. This is a long backed hill, or natural terrace, that affords a series of delightful views. The distant peeps are scarcely profitable investments for the camera, magnificent as the panorama is with the ruins of Bolton Castle and Middle- ham right and left; but some lovely woodland scenes, especially with the graceful silver birch in the foreground, may be secured with advantage Wensley village, with its church tower and surrounding foliage, makes a nice picture; but it is too small from here, and the photo grapher will do well to take it at closer quarters. Middleham, a very fine ruin, is situated, unfortunately, in a stretch of uninteresting landscape; still, by approaching close to the structure — it is but two miles off — some grand views can be secured of this old stronghold of the famous king-maker. Middleham Castle, indeed, is not only a historical pile, but is familiar to all readers of Shakespeare and Lytton. Its vast extent can only be fully appreciated by walking about and among the standing walls and solid grey buttresses. Edward IV. is said to have resided in the castle and to cruel Hunchback Richard it certainly belonged for many years. But perhaps Middleham will best be remembered in connection with “ The Last of the I Barons,” for much of Lord Lytton’s famous novel is laid