1. Test overview.

This test is used to adjust precisely the principal lens to obtain a maximum sharpness and of the required enlargement ratio (CoeffG).
For that, the scanner will scan a target film, and will find a sharpness level in the middle of the film, as well as the size of the image to determine the enlargement ratio. The user will need to adjust the principal lens to increase the sharpness level and to obtain the required enlargement ratio.
If the sharpness is incorrect, the customer could complain that the scanned images are not sharp enough. If the enlargement ratio is incorrect, the customer could complain that too many of the scanned images are cropped or that there are dark edges on the edge of the scanned images.

2. Test conditions.

This test relates to the 135 Film carrier inserted in the scanner.
The 135 Film carrier must be inserted in the scanner to carry out this test.
The 135 Film Colour Target Film must be used for this test (ref. 070 100 415A):
The acceptance of the test is automatic.
No parameter is saved.

3. Pre-requirements.

• 135 Pre-Sharp Test is accepted to ensure that the pre-setting of sharpness is made.
• For a phase of adjustment from the start, the high and low screws of the film carrier adjusted by default (17,7mm).

4. Test Realisation.

Click on RUN to carry out the test. A message will appear asking to enter the theoritical size of the image (written down by hand on the film, about 2200). When it is done, click on OK A message will be displayed requiring the insertion of the 135 Colour target film. When the film is inserted (caution watch for the direction of film), click on OK.
Note : the colour target film consists of :

• First exposure on which values are written down by hand, in particular the sharpness value needed for this film, as well as the size of the theoretical image of this film (for CoeffG).
• Second virgin exposure on which the scanner will calculate the sharpness level.
• Other exposures identical to the first but not used.

the scanner will scan the first and the second film exposure then will display an image mixing :

• the part of the second image where the calculation of the sharpness level was made.
• part of the first image where you can see the sharpness level to be reached, size of the theoretical image and where the measurement of the size of the image is done.

SHARPNESS :

The sharpness level calculated is displayed at the top in dialog box MIDDLE.
In dialog box "MIN TO REACH", enter the value written down on the film (about 70, according to films).
Note : the value of sharpness can vary from one scanning to another, sometimes of 4 or 5 points. It is due to the fact that a film is never scanned exactly at the same place.

COEFFG :

The enlargement ratio is calculated using the automatic detection of the crosses (which are at the top and bottom of the image) (see Automatic crosses detection for more information on this subject).
The measured value of the size of the image is registered in dialog box MEASURED. This value corresponds to the distance in pixel between the cross at the top of the image and that of the bottom of the image. The theoritical value is displayed in dialog box EXPECTED. The ratio corresponds to the calculated value of MEASURED / EXPECTED.
The right part of the window indicates a history of the positions of the principal lens, in order to remember their position.
Click on OK for come off the window, The result of the test is displayed on the screen.

5. Test acceptance.

The test is accepted if the sharpness AND the coeffG are correct :

SHARPNESS :

The ascertained sharpness in the middle of the film must be higher than 85% of MIN TO REACH.

COEFFG :

The coeffG (value Measured / Expected) must lie between 0,9973 and 1,0027.

6. Other affected tests.

If the sharpness incorrect, the following tests will be affected :

• 135 Sharp Top-Bottom
• 135 Cal Encoder 2
• 135 Cal RGB-IR

7. Trouble shooting.

• If The test is rejected : because of sharpness level or due to the coeffG, it is necessary to screw or unscrew the lens then to start again the test. The ultimate goal is to reach maximum sharpness with the correct coeffG. But if it proves difficult to obtain on site, a compromise between a correct sharpness and a correct CoeffG will be acceptable.
• If The test is rejected with a coeffG ouside from the nominal CoeffG : there is little chance that it can be rectified while turning the lens (likely risk of spoiling the sharpness to obtain a correct coeffG). In this case, it is necessary to change the scanner to re-reset it in the factory . Meanwhile, if the customer does not complain, sharpness is preferable to coeffG (more visible on the prints).
• If The test is rejected with the message " Nil value for sharp max " : this means that value MIN TO REACH was not entered, it remained to 0. Start again the test and enter the value.