This section is from the book "Modern Photography In Theory And Practice", by By Henry G. Abbott. Also available from Amazon: Modern photography in theory and practice: A hand book for the amateur.
Let us now take a photograph together, in order that we may better understand our camera, its attachments, our plates and the value of our records. For convenience sake we will follow the entry in our "Exposure Record." We have loaded our plate holders with No. 26 Seed plates and we are going to take a picture of a yacht which is just about to enter the harbor on a bright day, at 10:30 in the morning. Our three plate holders, holding six plates, are all in the back of the camera box. Fig. 12 illustrates a tripod, a frame consisting of three movable wooden legs held together at the top by a cap-piece which is technically known as the "head." There are many different styles of tripods on the market and it makes but little difference which we select so long as we secure one which is convenient, light and strong. It is important, however, that it be rigid and not easily made to tremble in case of a strong wind, for with a time exposure we cannot tolerate the slightest tremble on the part of the tripod or our picture will be ruined.
The tripod shown in Fig. 12 is a two-piece tripod, the lower legs being made to slide or telescope into the upper, so as to occupy but little space when not in use. Other varieties are made in three pieces and occupy less space still, In the head will be found a brass screw with milled head. This screw goes into the bottom of the camera box and the instrument is then held rigidly in place as shown in Fig. 13.
There is a right and a wrong way to use a tripod. Always see that one of the legs is directly in front and this will place a leg on each side of the camera. If this leg was at the back you would be constantly tripping over it while focusing. Again, the leg in front acts as a swivel on which to turn the entire outfit, and by moving the front leg you can raise and lower the camera without touching the other two.. Our lens is pointing toward the west while the sun is in the south, so there is no danger in this quarter. We must always aim to have the sun anywhere but in front of the camera, but it must be borne in mind that shade is as important as light and that it takes both to make a pict-ire, therefore it is not advisable to have the sun directly back of us, for although there will be no danger of it entering the lens when in this quarter, yet the shadows will be away from us and will not show in the picture bit we will get a rather glaring picture devoid of interest. If we were to expose a plate while the camera was pointing towards the sun we should certainly ruin the plate, because the direct rays of the sun would enter through the lens and strike the plate. We now let down the front of the camera box, draw out the bellows and drop down the bulb as shown in the illustration. We will now open the door which we see on the side of the camera box and take out the three plate holders and put them in our pockets or in our carrying case, if we have one. We allow the ground glass in the rear of the box to snap up close to the bellows by pushing the little brass button which we see on the side. We now open the little door in the rear of the box so we can see the ground glass. We turn the little dial just above the lens until the hand points to T and then press the bulb. This opens the shutter as previously described. We now place the little hand just under the lense until it points to 8, which opens the diaphragm to an 8 stop. If we now look at the instrument from the front it will appear as shown at Fig. 4, except that the index at the top points to T and the diaphragm points to 8.
We now spread our focusing cloth, usually made of rubber cloth, over the back of the box, and insert our head under it in order to see what the ground glass shows. With our head still under the focusing cloth we reach the right hand around in front of the camera and move the brass lever, previously described, which binds the bellows in position. We now move the bellows backward and forward until we get a good sharp image on the ground glass.
The water appears to be running up hill, and the yacht, water and all, appear to be upside down. The latter is just what you should expect, as all images on the ground glass are reversed, or upside down, but the former is caused by the camera being out of level. Proceed to level up your camera by drawing in one leg or letting out the other until the instrument stands perfectly level, then you will find that the water is no longer running up hill.
The yacht is moving towards us, however, and it is impossible to keep it in focus for any length of time, and finally we have to select one which is farther away and try again. We get all ready this time without the aid of the ground glass. We press the bulb to close the shutter, and place the index above the lens at fa leaving the diaphragm at 8. We insert a plate holder in the back of the camera, between the ground glass and end of the bellows. We pull the lever A, Fig. 4, over to the left until it reaches the point F, when a click is heard and we know the shutter is set. We now draw the slide of plate holder, which is number 3, and draw the bellows out until the pointer on the scale at the side points to 100. Our yacht is still some 300 feet away, and we watch it in the view finder, keeping it in the center as nearly as possible. When it has reached a point about 225 feet away we press the bulb and it is done. We now carefully insert the slide in the holder, being sure not to allow the light to leak in, by throwing the focusing cloth over camera and inserting the slide as directed and as practiced in the dark room.
The view we have taken is what is technically known as a "snap shot." It was a rapid exposure at a moving object. It was impossible to focus it on the ground glass because it was constantly coming closer to us, and it was equally impossible to expose the plate for any length of time for the same reason.
Before developing the plate we will take another picture, this one an entirely different view, with different surroundings. We will go up the south bank of the river so as to have the sun at our back. On the north bank is a dense grove of trees; the sun is shining brightly, and the foreground is well lighted. Away back among the trees it is very dark, and this view is going to test our lens for depth of detail and rapidity. We set our camera up again and proceed to focus on the ground glass. This we can do very well, although the wind is beginning to blow strongly, for we can focus on the tree trunks, which are stationary. We leave the diaphragm at 8 stop, and proceed to move the front of the bellows backward and forward until we get a clear, sharp image on the ground glass. We now bind the bellows in this position by means of the lever in front. and put our plate holder in position again, with plate 4 towards the bellows. We close the shutter, adjust the shutter mechanism, and study the scene before us for a few minutes. It is a dark subject for a "snap shot," and yet the water in the foreground and the leaves on the trees are in motion, and if we give it a time exposure this motion will certainly blur our picture and spoil it. We therefore conclude to try a compromise and give the view a 1/10 second exposure. This exposure will be short enough not to show the motion of the leaves and will be perhaps long enough to bring out the details of the trees in the foreground, at least. There are no cut and dried rules in photography for exposure. Everything depends on the nature of the view and the kind of light. There is but one good rule in regard to exposure, and that is an old one; it is "expose for the shadows and let the lights take care of themselves," and yet in this instance it is not practical, for if we expose for the shadows our foreground will show motion perceptibly. "Then all exposures are simply guess-work," you will say. Yes, all are guess-work in a certain sense but guess-work based on experience. This experience you will gain as you go along and if you keep a record book you can refer back to similar subjects and conditions and note your successes or failures. Now how do you know that you have not made both exposures on the same plate and ruined both? Because, first, you have replaced our plate holder slide with the dark side out, which tells you that this plate has already been exposed and second, because you keep a record and your record book shows that the plate in holder 3 was exposed on the yacht scene and the plate in holder 4 was exposed on the wood scene. Always fill out the entry in your record book as soon as the exposure is made. Never put it off and rely on your memory to fill it in at another time.