1. Test overview.

This test is used to adjust the film carrier (the principal lens having been sorted out with the 135 Film carrier) in a precise manner to obtain a maximum of sharpness (Sharpness) and the expected enlargement ratio (CoeffG).
For that, the scanner will scan a target film , and ascertain a sharpness level in the middle of film, as well as the size of the image to define the enlargement ratio. The user will be brought to adjust the screws of the film carrier to increase the sharpness level and to obtain the expected enlargement ratio.
If the sharpness is not correct, the customer could complain that the scanned images are not sharp enough. If the enlarging 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 APS film carrier inserted in the scanner.
The APS film carrier must be inserted in the scanner to carry out this test.
Film APS Colour Target Film must be used for this test (ref. 070 100 416A):
The acceptance of the test is automatic.
No parameter is saved

3. Pre-requirements.

• 135 Sharpness-CoeffG Test is accepted to ensure that the principal lens is set so as to obtain a correct sharpness.
• APS Pre-Sharp Test APS Pre-Sharp is accepted to ensure that the pre-setting of sharpness is carried out .
• For a phase of adjustment from the start, the high and low screws of the film carrier adjusted like those of the 135 Film carrier.

4. Test realisation.

Click on RUN to carry out the test. A message will be displayed requiring to enter the cross theoritical value which is in the centre of the film (written down by hand on film, about 1500). When it is done, click on OK. A new message will be displayed asking the insertion the APS colour target film. When the film is inserted Note : The colour target film consists of :

• First exposure on which values are noted by hand, in particular the value of sharpness to be reached 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 level of sharpness.
• Other exposures identical to the first but not used.

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

• the part of the second image where the calculation of the level of sharpness was made.
• part of the first image where the level of sharpness seen is to be reached, size of the theoretical image and where the measurement of the size of the image is taking place.

SHARPNESS :

The calculated sharpness level is displayed at the top in box MIDDLE.
In box "MIN TO REACH", enter the value written down on the film (about 30, according to films). Note : the sharpness value can vary from one scanning to another, sometimes from 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 screws of the film carrier, in order to remember the actual position.
Click on OK to exist the window, The result of the test is displayed on the screen.

5. Test acceptance.

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

SHARPNESS :

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

COEFFG :

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

6. Other affected tests.

If sharpness is incorrect, following tests will be affected :

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

7. Trouble shooting.

If The test is rejected : because of the sharpness or the coeffG, it is necessary to screw or unscrew the lens then restart the test. The ultimate goal is to reach maximum sharpness with the correct coeffG. But this being difficult to obtain on site, a compromise between a correct sharpness and correct CoeffG will be reached.

If The test is rejected with a coeffG very far from the nominal coefG : check the adjustment of the 135 Film carrier. If the sharpness and the coeffG of the 135 Film carrier are correct, those of the APS film carrier must be it too.

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 while entering this value.