The correct ideal shutter has yet to be invented. Certainly there are already many patterns to choose from, but there are also many important requirements which ought to be embodied in an ideal instrument that few, if any, will be found perfectly satisfactory in all ways.

There are three kinds in general use; those working between the lenses, those which can be used either before or behind the lens, and the focal plane working in front of and close to the sensitive plate. The between-lens type, of which there are several good patterns on the market, are small, light in weight, and work very quietly, and may be used for instantaneous exposures of wide range, in addition to what are known as automatic and time exposures. If only one lens is to be used, a shutter of this kind will answer all practical requirements for anything except very rapid exposures; but if more than one lens is in use, then this type is not suitable unless each lens has a separate shutter attached, which, of course, means not only extra expense, but extra weight.

A good type of shutter for working before or behind the lens is that known as the roller-blind, which can be attached to the camera front, and will enable different lenses to be screwed into the same flange by means of adapters, or by having different fronts to fit the same shutter. The Thornton-Pickard Manufacturing Company make two well-known shutters of this kind, one, the ordinary " time and instantaneous/9 and the other, the " silent studio" One of the most important requirements for the Nature Photographer is a shutter that will work without noise, and the " silent studio " can claim to be one of the best in this respect. For a really silent one the best I know is the " Central " shutter, which may be had from Messrs. Dallmeyer, Ltd. This gives time and instantaneous exposures and fits on the lens hood or tube. Adapters can also be had enabling it to be used with several different lenses, and the price is also very moderate. A shutter which fits on the front of the lens has the advantage of protecting it from injury, or from moisture during any necessary wait for the purpose of making an exposure.

The focal plane pattern is the only kind which should be used for really fast work, say for exposures between the one-hundredth and the one-thousandth of a second. This type of shutter has been recently much improved and is now available for either time or instantaneous work. It can be built into the framework of the camera (as in the case of the Reflex types) or used at the back of the ordinary stand-camera, the dark slide or plate-holder then fitting into the back of the shutter. For efficiency, this shutter is far ahead of all other types, and work of a marvellous character can be obtained by its aid. It is, however, bulky and expensive, and while I should not think of buying a Reflex camera unless it had a shutter of this type, I do not think it would often be wanted on a stand-camera. The beginner, at least, is not likely to feel the need for it, and a shutter that will give fairly efficient exposures of between the one-fifteenth and the one-ninetieth of a second, in addition to time, will be found to meet all his earlier requirements.