مثال عن كيفية الإستفادة من عدة جداول مختلفة ١_a .. كتاب المرشد العملي

An example of how to take advantage of several different tables

Assuming that I was going to photograph a postage stamp on an envelope and I used a 50mm focal length lens with a 35mm camera, and the distance of the postage stamp from the lens = 7.5 cm (i.e. 3 inches).

There is no doubt that the previous circumstances called for the use of an additional bellows extension to be placed between the lens and the body of the camera, between the following:

1- The measure of transmission in this case.

2- The length of the bellows (i.e. the distance between the lens diaphragm and the film).

3- The number of stops to be increased.

4- The amount of the exposure factor (i.e. the required increase in exposure) as a result of the increase in the bellows extension.

E - Assuming that the exposure meter has dictated a reading of 20 with a nursing speed of one second (i.e. when the speed of the cinema camera = 24 images per second with a shutter angle of 180), what is the focal number No. What is new according to which it is necessary to estimate the correct exposure in this case, and that is if we want to fix the exposure speed as it is (from a second)?

6 - It is assumed that the reading of the exposure meter = 8 40 with an exposure speed of one second, as in the previous case, then we saw when photographing that we fix the diaphragm aperture as it is, i.e. we fix the focal number No. We shout at the exposure speed, so what is the new exposure speed?

7- Indicate each of the shutter angle of the camera, the camera speed that fits the cinematic nursing speed, and the exposure speed that you found in item 6 above.

8 - Assuming that the reading of the exposure meter = 408 with an exposure speed of one second with a film whose sensitivity is 18 DIN, and assuming that in these circumstances you have seen keeping the two exposure factors, i.e. the No. And the exposure speed is as it is, so what is the speed of the film’s sensitivity that fits an increase in exposure of eight times, assuming that you have the ability to choose the film with the appropriate sensitivity speed?

9 - Assuming that you want to fix both nursing workers as they are in the previous case, i.e. 208, with a velocity of one second, and if the amount of incident light at that time = 100 feet / candle, then you decide to increase the amount of incident lighting to compensate for the amount of the required increase in exposure that I found it in the fourth question. What is the required amount of incident light at that time?

the answer :

1 - From Table No. 44 p. 91, we find that the transmission scale = 2: 1

2- From the same table No. 44 p. 91, we find that the length of the bellows, i.e. the distance between the diaphragm of the stapler and the film = 6 inches.

​​​​​3 - From the same previous table No. 44 p. 91, we find that the number of stops that must be increased = 31 stops.

4 - From the same previous table No. 44 p. 91, we find that the amount of increase in exposure factor . = x 9

5 - From Table No. 53 p. 113, we find that if the focal number estimated by the nursing scale is - = . , the new f-number appropriate to the amount of overexposure should be a number between 2.8, 20, 25. . For approximation, we will assume that it is 4028 . This is taking into account that table No. 53 p. 113, although it was set to indicate the appropriate focal number for the filter factor, it can also be used to indicate the appropriate focal number for the amount of exposure increase.

6 - Since it has appeared to us that the exposure factor = x 9 . ... the necessary exposure speed = ! That is, almost a second.


7- From Table No. 29, Part One, p. 52, we find that it is possible to make the exposure speed = E seconds, if we follow what we mention in the following table:

8- If we consider that the amount of visitation in exposure is synonymous with the candidate factor in Table No. 57. 121, we find that the appropriate film sensitivity speed = 27 DIN.

9 - Since we have deduced the answer in item 4 that the exposure factor 9 = Exposure Factor

... The amount of falling light must be = 900 feet / candle, if we want to keep the nursing staff as they are