factor in successful camera practice. Bearing in mind the frequent restrictions referred to respecting length of exposure, and the generally necessary use of color screens, experience teaches that f/12.5 is about the smallest stop that can be habitually used with whole plate lenses in comprehensive stand camera work when fully exposing plates.

Here we reach the first justification of our divisions, which is that lenses exceeding about 14 or 15 inches equivalent foci have so little depth of field at the required f/12.5, that many of our whole plate negatives making direct prints closely approximating our predetermined effects, break down in enlarging into something very different in appearance, often decidedly disappointing. At any rate the preconceived result is lost.

Hence, we have here reached a natural limit. natural limit. A limit characterized by results of sufficient size to be very satisfactory for book illustrations, portfolios, etc., but too small for really effective appearance upon the wall in more than exceptional cases, and yet at the same time unfortunately frequently inherently unsuitable for enlarging purposes. Simultaneously, the limit of ordinary portability of camera and accessories, lenses, shutter, plate-holders and plates, focussing glass and cloth, tripod, etc., has also been reached.

Here then we must either reconcile these inharmonious conditions by providing two or more sets of apparatus of differing dimensions, or make a really radical choice of one all-round size. This choice, from the nature of things, will be more or less a compromise, but not necessarily a disappointing one. it be in the direction of smaller instruments, the optical advantages will increase in much greater degree than plate dimensions are reduced, and the convenience and general ease of working the smaller sizes are most grateful.

The optical advantages are of course due to the fact that on the same basis of relative aperture, as we arithmetically reduce the equivalent focal length, we gain in depth of focus and field in geometrical ratios. This is an enormous advantage from an enlarging point of view. Moreover, on the same basis of depth our relative apertures and speed are vastly increased, greatly widening the choice of subject and lighting.

In general terms it may be said that the smaller the original negative, other things being proportionately equal, the more

suitable it is for a given enlargement, provided that in enlarging the stage of granularity due to the structure of the silver image is not reached. However, in actual practice 34 x 44 inches may safely be designated the minimum limit; 4 x 5 inches has a decided advantage in that it yields more presentable direct prints, but if systematic enlarging is adopted, larger than this, it is, perhaps, best not to go. The comparatively unimportant increase in size of half plate and 5 x 7 inches prints over 4 x 5 inches does not satisfy, and the optical loss for enlarging purposes, and increase of weight, bulk, and expense are decidedly great.

I would, therefore, venture to suggest, if but one general utility camera can be had, that great stress be laid first upon the question of portability, because the annoyance of excessive weight and unwieldiness during manipulation are constant and will in time wear out all but the keenest enthusiasm.

As a corollary, whether or not one is willing to enlarge much or little appears to come in order of force. If you are prepared for much enlarging, it seems conservative to recommend 4 x 5 inches as the best choice.

On the other hand if you can be generally contented with the really excellent dimensions of direct prints from whole-plate negatives; only wish to occasionally enlarge some especially successful result for home or exhibition walls, or confine yourself for enlarging purposes to appropriate subjects; and, in addition, can be serene under moderately wearisome physical burdens, then in that case you will probably congratulate yourself upon the choice of their classic size.

If, however, you desire to be in position to see most of your direct work upon the walls; can remain tranquil with a moderate yet effective size for that purpose, even when your modest prints are hung in the company of veritable monsters; can further reconcile yourself to ever present punishing weight and bulk, then the 8 x 10 inch size, notwithstanding its inherent restrictions regarding subjects and lighting, will very likely prove the most permanently satisfactory of any that can be worked for general purposes. Of course, the negatives, as a rule, will not be so fit for amplification as those from whole plate cameras.

Above 8 x 10 inches the increase in weight and bulk are ex

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cessive. But most serious of all, the depth of field, etc., of the associated lenses become so slight that the use of smaller stops is imperative, greatly increasing time of exposure, and very seriously limiting choice of subject, lighting, and other conditions. Inasmuch, therefore, as it may safely be said that sizes larger than 8 x 10 inches are unsuitable for general use, they will be dismissed from further consideration here.

Referring again, in passing, to whole-plate cameras, attention should be called to the fact that broadly speaking telephoto negatives do not enlarge well, but that they can be conveniently taken direct up to and including whole-plate size.

Hand Cameras. With stand cameras we had to deal with size in relation to portability, only on a basis of plate dimensions, and not with respect to form or type of camera, i. e., whether box or folding. The double consideration here presents itself and involves not only the portability of instruments, but their essential suitability for various purposes as well. The optical restrictions, however, are of the same nature for all, except those of the reflex type. Our main classification then is:

First, box scale-focusing hand cameras; Second, folding hand cameras; Third, reflex hand cameras, exclusively of the box type.

Simplicity and clearness suggest that we consider size first from an optical point of view, as limitations of this kind apply equally to all hand cameras of our first two divisions. This having been done we will examine the question in relation to bulk and weight of apparatus according to its type, i. e., box or folding. Proceeding in this fashion we are at once confronted with seriously conflicting conditions.

First.-Exposures must not exceed about one-eighth second, because aside from any movement of or in the subject itself, one-eighth second is nearly if not quite the maximum exposure period that can be relied upon to yield sharp negatives with cameras operated while held in the hands. The average of judicious hand cameras exposures, exclusive of high speed work, may be placed at from about one-sixteenth second to 1/32 second.

Second. To get fully timed negatives on average hand camera subjects with such brief exposures, relative apertures of f/8 or greater must be generally used. This involves less.