Question: Rodenstock Depht of field calculator

Question: Rodenstock Depht of field calculator

Last week i buy the Rodenstock Depht of field calculator.

I not understand as it's estimated the angle of inclination (alfa) of the
camera's monorail against the optical axis.

Do you help me to understand that?

Many thanks for all to help me.

M.Spoto

In article ,
"Massimiliano Spoto" wrote:

Question: Rodenstock Depht of field calculator

Last week i buy the Rodenstock Depht of field calculator.

I not understand as it's estimated the angle of inclination (alfa) of the
camera's monorail against the optical axis.

Do you help me to understand that?

Many thanks for all to help me.

M.Spoto

The instruction sheet that comes with it shows what you are asking. So
does the calculator.

It wants to know if the camera is level or pointed up or down and, if
so, by how many degrees.

--
To reply no_ HPMarketing Corp.

"Massimiliano Spoto" wrote in message
...
Question: Rodenstock Depht of field calculator

Last week i buy the Rodenstock Depht of field calculator.

I not understand as it's estimated the angle of inclination (alfa) of the
camera's monorail against the optical axis.

Do you help me to understand that?

Ciao Max,

You may want to check chapter 2 of this document:
http://www.bobwheeler.com/photo/Surveys/Survey.pdf

It is not quite clear to me what you don't understand. I do not have the
Rodenstock calculator but having seen Bob Wheeler's document, I can tell you
the following opinion: as per the 2 small drawings of a camera showing the
angle alpha for 2 separate conditions at the top right corner of the
Rodenstock calculator (as shown in Bob's PDF document): the angle alpha is
the angle between the rail or bed of the camera and the lens optical axis
BEFORE THE LENS IS TILTED, in other words, the angle of the rail/bed of the
camera with respect to a horizontal line. If what you don't understand is
why the calculator asks for that angle, it seems the reason is that the
"extension difference" is the horizontal distance you have to displace the
rear standard of the camera to have the nearest and farthest points of
interest in relative sharp focus (one at a time), but because the
measurement of the "extension difference" is made on the rail or bed of the
camera, if the rail/bed is inclined, the extension you measure on the rail
is not the actual extension that should be used in the calculations, to
avoid having you enter the actual horizontal extension difference, the
calculator ask you for the angle alpha (step 1) and then for the "extension
difference" as measured of the rail or bed of the camera, the calculator
then uses the angle alpha to translate that inclined measurement to a
horizontal measurement. When you set the alpha angle in the calculator,
that in fact may just be multiplying the extension difference as measured on
the rail/bed by the cosine of the angle alpha. If the bed/rail of the
camera is not tilted, the inclination is zero degrees and Cosine of zero
degrees is one, so the displacement measured of the rail/bed is the actual
"extension difference", all this is hidden to the user, it is part of the
magic of what the calculator does for you.
Hope I am not confusing you.

Guillermo

"Massimiliano Spoto" wrote in message
...
Question: Rodenstock Depht of field calculator

Last week i buy the Rodenstock Depht of field calculator.

I not understand as it's estimated the angle of inclination (alfa) of the
camera's monorail against the optical axis.

Do you help me to understand that?

Ciao Max,

You may want to check chapter 2 of this document:
http://www.bobwheeler.com/photo/Surveys/Survey.pdf

It is not quite clear to me what you don't understand. I do not have the
Rodenstock calculator but having seen Bob Wheeler's document, I can tell you
the following opinion: as per the 2 small drawings of a camera showing the
angle alpha for 2 separate conditions at the top right corner of the
Rodenstock calculator (as shown in Bob's PDF document): the angle alpha is
the angle between the rail or bed of the camera and the lens optical axis
BEFORE THE LENS IS TILTED, in other words, the angle of the rail/bed of the
camera with respect to a horizontal line. If what you don't understand is
why the calculator asks for that angle, it seems the reason is that the
"extension difference" is the horizontal distance you have to displace the
rear standard of the camera to have the nearest and farthest points of
interest in relative sharp focus (one at a time), but because the
measurement of the "extension difference" is made on the rail or bed of the
camera, if the rail/bed is inclined, the extension you measure on the rail
is not the actual extension that should be used in the calculations, to
avoid having you enter the actual horizontal extension difference, the
calculator ask you for the angle alpha (step 1) and then for the "extension
difference" as measured of the rail or bed of the camera, the calculator
then uses the angle alpha to translate that inclined measurement to a
horizontal measurement. When you set the alpha angle in the calculator,
that in fact may just be multiplying the extension difference as measured on
the rail/bed by the cosine of the angle alpha. If the bed/rail of the
camera is not tilted, the inclination is zero degrees and Cosine of zero
degrees is one, so the displacement measured of the rail/bed is the actual
"extension difference", all this is hidden to the user, it is part of the
magic of what the calculator does for you.
Hope I am not confusing you.

Guillermo