This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Lens. The ordinary hand-camera lens may be employed for At-home Portraiture, but will be found to work rather slow. Beginners who do not care to purchase a better lens for this work will find the portrait attachment an added power. This attachment slips over the barrel of the regular lens, and can be obtained at a cost of $1.50, or less. (See "Lenses.")
256. An anastigmat lens of the proper focal length gives most excellent portrait results, and at the same time serves as an all around instrument, being applicable to all classes of work. The focal length of the lens should equal the diagonal of the plate for which the lens is to be used. If it is your intention to make At-home Portraiture either a special feature or a business, the anastigmat portrait lens should be employed.
Stopping Down The Lens. As the average lenses of the rectilinear and achromatic type have a sufficient amount of depth of focus to include all of the subject, such lenses should not be stopped down when used with a hand-camera. By stopping down the lens the depth of focus is increased, and as a greater depth of focus causes more sharpness throughout the picture space, the atmospheric effect is lost. Sometimes, when making photographs of full length figures, it may be necessary to stop down the lens, because if a small opening is not employed some portion of the subject may be out of focus. In this case stopping down should be carried only far enough to produce a reasonably sharp focus.
258. For bust work always use the largest stop, even though focusing sharply on the face causes the back of the head to become slightly diffused.
Softness In The Lighting. Always aim to secure softness in lighting, as results will not only be more pleasing, but the required length of exposures will be greatly reduced. Effects produced by the employment of a small source of light result in strong contrasts, and for this reason it is necessary to diffuse the light in such a manner as to reduce the density of the high-lights. In doing this the light throughout the room is diffused, and the general illumination, which did not exist before the diffusion of the light, very materially aids in the illumination of shadows, thus reducing the required length of exposure.
Position Of The Head. The face should be turned toward the source of light to a degree sufficient to obtain catch-lights in both eyes. The tip of the shadow cast by the nose must just touch the shadow of the cheek. Hence there is, practically, but one position in which the face may be placed if an absolutely true Plain Lighting is to be made. Turning the face too far toward the light will cause an excessive spread of illumination over the face, resulting in a flat effect. Turning the face too far away from the light, will produce heavy shadows on the shadow side, and the negative will contain an excess of contrast.
261. As a rule, in At-home Portraiture the camera should be placed as close to the line of the window as possible. In this position both ears of the subject may be visible on the ground-glass, presenting a full face view of the sitter. The position of the camera, of course, may be altered as well as that of the subject, to obtain the most pleasing outline of the face. For the average subject the camera should be placed on a level with the chin.