Lesson 2: reversed lens as a close-up lens

- load (open) the 28.5mm wide angle lens for SLR (28.24mm)
- invert all
- shift all lenses by -52mm
- load (open&add) the 100mm telephoto lens (99.74mm)

the calculated magnification = 99.74mm / 28.24mm = 3.53 (or 3.53:1)



- switch to simulation mode
- do not move the sensor (telephoto lens is focused to infinity)
- decrease the object distance until focus reaches the sensor (39mm)
- switch on the second object
- give some angle or height to any object
- read the measured magnification

measured magnification = 3.53

- select lenses from No. 1 to No. 7 (elements of the wide angle lens)
- move them along Z axis by uppermost adjustment
- let see how independent the magnification is

New lens in the example package!

Data of a simple 100mm 1:2.8 telephoto lens are available (4 lenses in 4 groups).

Example files are available!

You can download the example package from here, and it contains the following lenses:

- normal lens for rangefinder cameras (50mm 1:2 - 6 lenses in 3 groups)
- double-gauss normal lens for rangefinder cameras (50mm 1:2 - 6 lenses in 4 groups)
- long telephoto lens (170mm 1:3.5 - 9 lenses in 8 groups)
- wide angle lens for rangefinder cameras (20mm 1:4 - 9 lenses in 4 groups)
- wide angle lens for rangefinder cameras (35mm 1:2.8 - 7 lenses in 4 groups)
- wide angle lens for SLR cameras (28.5mm 1:2.8 - 7 lenses in 6 groups)
- close-up lenses: 1D, 2D and 3D

The first lesson: the effect of close-up lenses

- let us suppose that you have a normal lens
- specification shows 1:10 (0,1x) maximum magnification
- download the example package and unzip it
- press the open button, find the downloaded examples
- select the "normal_simple.txt" file and load it
- press the simulation button



- the focal point located on the sensor
- switch on the second object
- give a not zero angle to the object
- decrease the object distance until magnification reaches the specified maximum value
- click on distance input field and use arrow keys to fine adjustment
- read the minimum focusing distance (from front vertex, not from the sensor)
- the focus located beind the sensor now
- move a "Z" cursor over the focus, and read the cursor position
- the distance between the sensor and the cursor is the maximum mechanical extension of the lens



- press the editing and preferences button after
- memorize the position of sensor
- type in the cursor position into the sensor position input field



- the focus located on the sensor again
- go back to editing
- press Open & Add button
- select the 2D close-up lens
- go back to simulation
- the focus located before the sensor now



- decrease the object distance until focus touches the sensor
- read the new magnification, this is the gain of the close-up lens
- read the new minimum focusing distance



- go to preferences
- set the sensor position to the original value
- go to simulation
- increase the object distance until focus touches the sensor
- read the new maximum focusing distance (instead of infinite)